Population

Also see History of Bluebirds

PS:
Western Bluebirds are on the decline in California as are Ca Quail and other birds. Maybe not on some govt' list yet. The population growth, out of control development, and the high demand for housing is responsible for this. Threatened species is one of the main tools that I used when working on land acquisition to expand habitat areas and wildlife corridors around our local St parks lands. People did not see them for years until we began monitoring boxes. Many people have never seen a Western Bluebird. I love showing people the birds. They are thrilled they think a Bluebirds is a Scrub Jay.

They were not around when I was growing up.

Nancy

Dear Friends,

Yes, I would agree that Western Bluebirds are in decline in California, as are other native birds. The population boom, and development are all contributing factors, as are aggressive exotic cavity nesting birds and vandalism to the infant nest box programs here in California.

We all know about the European Starling and how it was introduced, but you may not know that during the filming of the 1963 movie The Birds, Alfred Hitchcock unknowingly became the Eugene Schieffelin of our time by releasing hundreds of European Starlings into the Bodega Bay CA area and now we have waves of them. Same applies to HOSP, as they breed unchecked in shopping malls and large buildings, plus the influx of large murder Crows to California is alarming too. Cat predation on California Valley Quail is the main reason their decline.

Vandalism to nest boxes is another challenge. Not more that a month ago I was checking out 3 Barn Owl nest boxes in the Castro Valley, CA (near Oakland), that had Barn Owl in them. My heart sank when I saw 2 bullets shot into each of 2 of 3 nest boxes made by a high powered deer rifles (looked like 30 cal.) I didn't bother to open them (I'll do that in July when we clean out Barn Owl nest boxes), but I'm afraid that will find the desiccated remains of the breeders inside. Another incident happened this past February in Novato, CA where a Barn Owl nest box was smashed to bits by a brick. The stupidity of human beings never ceases to amaze me.

Though there are those out west that are making in roads on installing nest box program, we all have to admit, nesting box program back east (either properly monitored or not) are light years ahead on us out here in the west.

In my opinion, the only way to turn it all around is to educate the unaware, properly install nest box trails, maintain same, seal up building to prevent unwanted cavity nesting by exotic cavity nesters and aggressively thin exotic cavity nesting birds to more tolerable levels.
...

John Schuster

Would someone with expertise in wildlife ecology please define "endangered", "threatened" and "declining"?

And, I'd appreciate clarification on the status bluebirds reached at their low point.

Did bluebirds at any point come close to "endangered" or "threatened"?

What is their status now?

Pauline Tom
Mountain City (no mountains) TX

On Sat 19 Mar 2005 at 12:57, Pauline Tom <ptom"at"austin.rr.com> wrote:

> Would someone with expertise in wildlife ecology please define
> "endangered", "threatened" and "declining"?

I'm no expert but answers are straightforward. From the 'Endangered Species Act of 1973' (ESA) as amended:

An endangered species is one that is in danger of
extinction throughout all or a significant part of
its range.

A threatened species is one that is likely to become
endangered in the near future in all or a significant
part of its range.

The terms apply to all living things. Our native Chestnut trees are endangered. Only a few survive due to the Chestnut blight and efforts continue to develop a blight-resistant strain from the remaining trees. In the interim, those of us who love Chestnut trees have to plant hybrids crossed with the Chinese Chestnut.

Another category, at least in Virginia and surrounding states, is the 'Watch List,' species in long term or rapid decline. The intent is to take action early to prevent species from becoming threatened or endangered.

A final category is 'rare,' meaning population density is always low in a species, either in a particular area or generally.

Basically, 'declining' means that the population of a species as measured by the Breeding Bird Surveys (see
http://www.mbr-pwrc.usgs.gov/bbs/bbs.html) and the National Audubon Society Christmas Bird Count (see
http://www.mbr-pwrc.usgs.gov/bbs/cbc.html) is lower by a significant amount in consecutive counts. Species can also be classified as stable or increasing. I also see 'recovering' used, meaning that an observed decline has been reversed. Normal counts vary both up and down.
Only when there is an identifiable trend are the terms declining or increasing applied.

> And, I'd appreciate clarification on the status bluebirds reached at
> their low point.
>
> Did bluebirds at any point come close to "endangered" or "threatened"?

First, those terms weren't in common use until after the adoption of the ESA. I can't speak for Bluebirds generally but in Virginia, the BB population reached its low point in the early 1960s. At that time, the Eastern Bluebird would have been classified as threatened state-wide. EABB were completely absent from much of their range within Virginia until amateur naturalists took action well ahead of the government programs to protect the environment.

Reasons were many. Wide use of pesticides eliminated their food supply. How many of us remember the trucks going by and mom yelling to close the windows as a fog of DDT was blown out to control mosquitoes? Many (possibly most) of the farmers used non-specific insecticides to increase productivity. There was no EPA monitoring back then and too many folks figured if some is good, more is better.
Competition for nest sites from English House Sparrows and European Starlings was significant and well documented by naturalists. Elimination of nest sites by land clearing for farms, logging and cutting for firewood and pulp wood was also detrimental. Together, the EABB went from very common in the early 1900s to rarely seen in Virginia in the early 1960s.

> What is their status now?

Overall, the Western Bluebird is in significant decline.
The Mountain Bluebird is also declining but so far the decline is listed as insignificant. The Eastern Bluebird is significantly increasing (or recovering, depending on what literature you read). For more detail, see http://www.mbr-pwrc.usgs.gov/bbs/trend/guild03.html to put in your own criteria and get results of the BBS (the
2004 data is still 'draft' and not completely analyzed).

Take care,

R J 'Tree' Greenwood
Catlett VA

In my last post, I left out a few things.

Before being added to the official list of threatened or endangered, there is a category of 'candidate.' A species can remain a 'candidate' for years while the experts try to come to agreement. Species that recover also remain on endangered and/or threatened lists long after they are no longer endangered/threatened because of the same bureaucratic inertia.

Another list is 'Species of Special Concern' (SSC). SSC is not defined by law. It's a category created by the Fish & Wildlife Service and apparently is the Federal Government's version of a 'watch list.' Someone please correct me if I'm wrong on this.

Most states adopted their own Endangered Species Acts to help protect their native wildlife. I'm very familiar with Virginia's program but not others. Our state lists are usually more up-to-date and accurate than Federal lists. Smaller amount of data for a smaller area is easier to manage and analyze.

Take care,

R J 'Tree' Greenwood
Catlett VA

http://www.state.ny.us/governor/press/year99/may11_4_99.htm

This is a link that tells when NY took the Eastern Bluebird off the Special Concerns List.

Evelyn

From: Keith & Sandy Kridler [mailto:txbluebirder"at"sbcglobal.net]
Sent: Sunday, March 20, 2005 8:02 AM
Subject: declines in BB population

Keith Kridler Mt. Pleasant, Texas
copied from Evelyn's post on endangered species in New York:

"Eastern bluebirds -- the official State bird -- were once plentiful in New York State until they began to dwindle in population around the turn of the century due to the loss of suitable habitat, mainly open fields and farms."

If you go back to the turn of the century and read "Useful Birds and their Protection" by Edward H. Forbush 1907 you will realize that the USA had just experienced record cold across much of the country from Montana south to Texas and then to the east coast of the US. From the late 1890 on into about
1902 record cold was responsible for wiping out MANY species of birds, plants (winter wheat, oats ETC,) and animals. (Cattle on the open range were virtually wiped out from Montana to Arizona east to the Mississippi. This huge "winter kill" loss of agriculture led to the first world wide economic depression in the late 1890's) Mostly the declines in birds were recorded in the northeastern states simply because there was a higher number of scientific studies done in this area from 1850 to 1890 to compare numbers for different bird species over a relatively "long" time frame.

Again in the 1940's and 1960's record cold and documented losses of bluebirds in the middle and southern states mostly from the late 1950's to the mid 1960's had the direct result of wiping out many species of birds like robins and bluebirds whose food supply was removed by snow and ice.

During this same time frame DDT which was actually one of the chemicals developed and funded by our government between World War I and World War II during the search for a replacement for "mustard gas" which could be used against enemy troops if they violated the Geneva convention. (Did you know that USA was the only country during World War II that killed thousands of troops in Italy with chemical weapons?)

DDT became a widely used insecticide when the chemical warfare research and development released DDT, Chlordane and all the other organo-phosphates for use as insecticides against the "army" of insects.

New York blamed "loss of habitat" for the declines in bluebirds but this is much too simple. World War I brought about the invention or major improvements and mass production of bull dozers, tractors, light weight engines for airplanes and chain saws, road building equipment, huge dredging equipment and small backhoe's became common. This equipment and the need for lumber for rebuilding Europe and America's booming population explosion beginning in the 1920's brought about the fall of all of the great expanses of virgin timber in the south eastern states from 1936>1956. Virtually EVERY last block of 300 acres or more of virgin timber fell in this time frame in the gulf coast (really everything East of the Mississippi.)

Hundreds of millions of acres of forest land in the US was turned into crop land starting in 1946 to 1957 to feed European and Asian people who lacked farm land, tractors, fuel, insecticides or seed grain stocks to feed themselves. During this time the USA exported record amounts of lumber, grain, cotton ETC. to rebuild the world.

When Europe and Asia caught up with farm production crop prices fell and many row crop farm operations failed and much of the southeastern USA was replanted with "yellow pine" starting in the 1950's continuing till today.

Most of the gulf coast region was actually mixed hardwoods instead of pine plantations. Hardwood forests provide better food sources for more species of wildlife. Few species of wildlife actually find enough food in massive plantations of solid pine forests.

The SIMPLE fact about the decline in all species of plants and animals is the human ability and need and willingness to convert the entire earth above and below the ground or in the oceans to produce food, water, fiber, metals and fuel for the benefit of only one out of the billions of species we share this planet with.

The real problem is that we want to blame a House Sparrow or a wasp or a raccoon or a poorly made nestbox for the decline in bluebirds but if you look at the other 700 species of birds in the US then MANY of them are also in decline and few of them are affected by introduced birds species. ALL of the extinct birds in the USA can be blamed directly on the expansion of the human race. KK

I think we are trying to improve the bad situation by having good nestboxes, monitoring, etc, not blaming it on that.

In "Bluebirds!" by Grooms & Peterson and "Bluebirds Forever" by Connie Toops, it states that the cold weather is the strongest factor in the diminishing population along with HOSP and Starling coupled with loss of habitat and chemical use. It also states that we will have periods of these severe cold spells and the bluebird populations will go low again. That is why I feel we will have to continue to help them have homes to live and supplement their diets in winter time.

Oh, how we need to reach our younger generation so when the time comes to pass the torch!!! Will be a success??

Evelyn

This is not a political fourm -- however I cannot let the statement by Mr.
Kridler go unchallenged:

he wrote: "Did you know that USA was the only country during World War II that killed thousands of troops in Italy with chemical weapons?"

I believe that is nonsense.

I assume he is referring to the ACCIDENTAL release of mustard gas at Bari, Italy in 1943.

That gas was stored on a US ship to be used for the protection of US troops IF THEY WERE FIRST attacked with the same.

The Luftwaffe happened to bomb that ship resulting in the release of gas.

It is quite illogical, to my thinking to call that an example of the American "use" of chemcial weapons.

President Truman had clearly and publically stated the US would not use chemcial unless they were used on us. We had every right to have protection available for our troops.

The USA did not start WWII and were under no obgligations to sacrifice our troops to chemical attacks which we knew (and which history has shown to be
true) were in the Axis military plans.

Our family had many members who fought to free Europe in WWII -- two were shot down and were prisoners of war and one lies buried today in France soil and I resent the misleading implications of that statement!

Bernie Daniel

Keith Kridler Mt. Pleasant, Texas
MANY Thanks to Bernie for knowing this. It was intended only to have people think about dangerous chemicals stored or used and what often does happen by accident when they are released. It was only to see if anyone knew this piece of trivia about chemical weapons during World War II as many on this list served so bravely during many different battles and wars over the years. My dad flew on many missions on B-24's while based in Italy for 29 months. Every time he flew enough missions to come home they raised the required number of missions needed to return.

Thanks again goes to MJ. I used the DDT bad guy chemical as a catch all. DDT probably is really safer for short lived birds and mammals than most of the chemicals that replaced it. According to USDA year books on chemicals many were developed, reanalyzed, improved ETC. during World War II in many different countries although USDA books tend to say Americans came up with all the best improvements or second generation innovations. Especially after the war we could not afford for insects or plant diseases to destroy 20>30% of farm crops.

The biggest losses to wildlife were not in the chemicals used but the changes to mechanized farming from the horse and mule farming days. In Mexico today the majority of corn farms are about 4.5 acres mostly farmed by hand or animal drawn plows still. In America the average corn farmer harvests more than 2,000 acres. I visited with a crop duster yesterday who contracted with Green Giant to spray 120,000 acres of green beans 15 years ago. He normally sprayed some fields every three days (not the same fields) in his region with either a pesticide, or fungicide to control some "pest".
They used 15 different chemicals that season most of them fungicides.

There is never a totally correct answer and NEVER a short answer to any
problem: Question freely what you read here and in newspapers! Question what you hear or see on the radio and TV. Feel free to add to a conversation!
Today very in depth research can be done at the "search" button on your
computer:-))) Today if a company or country spills or accidentally releases chemicals or hazardous materials lawyers and courts decide who is responsible:-)) KK

From: Bernie Daniel [mailto:bdaniel"at"cinci.rr.com]
Sent: Monday, March 28, 2005 7:53 AM
To: Evelyn Cooper; 'Elizabeth Zimmerman'; 'Bluebird L-mailing list'
Cc: 'Keith & Sandy Kridler'; 'John Schuster'; nancy.hanna"at"btinternet.com; 'Tree Greenwood'; 'PTom'
Subject: Re: Endangered vs threatened vs special concern vs extinction, listing by states

Hi All

If you get Bluebird the next issue will include a summary of some of the info on continental bluebird populations today.

This article is written by Jim Williams with some comments/statistics by myself and also perspective from some active western bluebirders.

There is no doubt that we need to take very close look at the western bluebird's status. It simply is not responding to our efforts to assist it like the other two species --the reasons for this might be many -- I could think of a number right off the top of my head -- but then what good is that? We need the real reason.

When I look closely are ranges based on the North American Breeding Bird Survey -- I am starting to wonder if the western is not getting pressure from the mountain on much of its range (except central CA). Just a thought but I'm going to do some analysis on that hypothesis.

Bernie

________________________________________
From: John Schuster [mailto:wildwingco"at"earthlink.net]
Sent: Monday, March 28, 2005 10:09 AM
To: Bernie Daniel
Cc: 'PTom'; 'Keith & Sandy Kridler'; 'Elizabeth Zimmerman'; nancy.hanna"at"btinternet.com; Evelyn Cooper; 'Bluebird L-mailing list'; 'Tree Greenwood'
Subject: Concerns about Western Bluebirds.

Dear Friends,

I haven't posted until now because it would be lengthy, but at our vineyards and others that Wild Wing Company is in involved we are not seeing a decline, but we are small compared to the rest of the state.

I don't think the Mountain Bluebird is a big factor to the decline of Western Bluebird populations, but I can report that several factors could be contributing to a decline of same.

A. Lose of habitat, population growth in the state, vandalism and that people just do not care has to considered.

As housing development is increased, Bluebirds are forced to retreat.

Vandalism is a factor, because those that are willing to install nest boxes are quickly discouraged by the destruction of nest boxes, usually throwing up their hands and give up. Also improper monitoring (if at all) seems to be rampant so eventually the HOSP takes over these trails forcing WEBB out.

People are also to busy and frankly don't give a damn. I notice this when every I talk to groups about Barn Owls and Bluebirds. They usually embrace Barn Owls (because of the obvious benefit of rodent control), but are reluctant to embrace Bluebirds seeing the Bluebird nesting boxes as just another expense and time consumer (though the Bluebirds eat loads of insects.)

B. Mammal predation, increase in exotic cavity nesting pest birds, and the state is over run with Crows.

Mammal predation is a concern, as Raccoon and Opossum populations are at an all time high here in the state. Thinning of Raccoon and Opossum populations is not even done anymore, so these aggressive nest robbers are free to do as they please.

We all know that EUSP and HOSP are a challenge, but Crows can do there fair share of damage as Crows are opportunistic feeders and will kill fledgelings. It seems like no one is doing anything about these pest birds, and I sometimes think I stand alone as the only one in the state that aggressively traps or shoots these avian vermin, so this too in a concern in my opinion.

C. Insects! I've noticed an increase in the Yellow Jacket populations over the years and Yellow Jacket killings inside nest boxes so this has to be factored. However, I believe an aggressive Yellow Jacket trapping program could help in this area, staging Yellow Jacket traps a few yards away for installed nest boxes.

I'm sure there are other factors to be considered, but the above are just a few examples I've noticed over the years.

________________________________________
From: Elizabeth Zimmerman [mailto:ezdz"at"charter.net]
Sent: Monday, March 28, 2005 10:17 AM
To: 'John Schuster'; 'Bernie Daniel'
Cc: 'PTom'; 'Keith & Sandy Kridler'; nancy.hanna"at"btinternet.com; 'Evelyn Cooper'; 'Bluebird L-mailing list'; 'Tree Greenwood'
Subject: RE: Concerns about Western Bluebirds.

I gather some folks with trails have seen local increases in Western bluebird populations, but overall it's in decline.

Seems like the key might be to figure out which of these or other factors are DIFFERENT for Western bluebirds compared to Eastern bluebirds. All of these, except maybe yellow jackets, are also problems for the eastern bluebird.

Maybe more nestboxes have been erected for eastern bluebirds?

________________________________________
From: John Schuster [mailto:wildwingco"at"earthlink.net]
Sent: Monday, March 28, 2005 10:42 AM
To: Elizabeth Zimmerman
Cc: 'PTom'; 'Keith & Sandy Kridler'; 'Evelyn Cooper'; nancy.hanna"at"btinternet.com; 'Bernie Daniel'; 'Bluebird L-mailing list'; 'Tree Greenwood'
Subject: Re: Concerns about Western Bluebirds.

Dear Friends,

Without a doubt, nest box programs on the east coast are light years ahead of us out here on the west coast.

If we truly what to see the Western Bluebird survive, we need to be more aggressive about our nest box program out here in the west.

-----Original Message-----
From: bdaniel"at"cinci.rr.com [mailto:bdaniel"at"cinci.rr.com]
Sent: Monday, March 28, 2005 11:46 AM
To: Elizabeth Zimmerman
Cc: 'John Schuster'; 'PTom'; 'Keith & Sandy Kridler'; nancy.hanna"at"btinternet.com; 'Evelyn Cooper'; 'Bluebird L-mailing list'; 'Tree Greenwood'
Subject: RE: Concerns about Western Bluebirds.

I agree completely -- the local hot spots are there and these are a tribute the those bluebirders -- but I afraid that on the continential level we are wining some battles but losing the war. We REALLY need to get on this -- in my opinion. As soon as I retire I am going top get back out west and then maybe I can help out.

Bernie

________________________________________
From: Bernie Daniel [mailto:bdaniel"at"cinci.rr.com]
Sent: Monday, March 28, 2005 11:16 PM
To: John Schuster
Cc: 'PTom'; 'Keith & Sandy Kridler'; 'Elizabeth Zimmerman'; nancy.hanna"at"btinternet.com; Evelyn Cooper; 'Bluebird L-mailing list'; 'Tree Greenwood'
Subject: Re: Concerns about Western Bluebirds.

John

A lot of good thought here.

I tried to respond earlier today but I think the new firewall at work is blocking my web mail port -- I can still read email to my home ISP at work but not send --really "dumb" system.

Anyway on your points:

A. Lose of habitat, population growth in the state, vandalism and that people just do not care has to considered.

This is possible -- but it is also possible to test it. I can look at the rate of development in Western range compared to Eastern and Mountian via the GIS. I'm not sure why vandalism would be part of it though -- amymore than anywhere else that is.

B. Mammal predation, increase in exotic cavity nesting pest birds, and the state is over run with Crows.

This one is also something that we could examine. Specifically what mammalian predators -- raccoons? or opossums? or feral cats? -- other?

Raccoons are a problem in the east but except for some isolated areas they are far below the house sparrow as threat to bluebirds. The house sparrow is found all across the continent but its densities are generally higher in the east as a rule. But that is another thing that could be tested -- the ratio of bluebird to sparrow over the three bluebird ranges.

As to crows I'm not sure they would be a specific problem for the westerns -- the American crow at least is found at much higher densities in the east relative to the west. Of course the Raven is strictly western. So I'm not sure that is the reason for the difference in the eastern vs western bluebird -- in addition the crow is just as dense over the mountain bluebird's range.

For eastern bluebirds I do not regard the starling as much of a threat to the nesting -- because we have engineered them out of our boxes -- but starlings are a major problenm as regards winter food supplies however and threats to woodpeckers. I have often wondered about the situation out west with the starling. But again by far the most dense concentrations of startlings are in the midwest and on the east coast of Virginia and N. Carolina -- though central California has their share.

I think the yellow jacket hypothesis is an interesting one do you think there is any hard data on the distribution of these critters through the State organizations? I'm curious as to what might draw yellow jackets to a bluebird trail? In the east paper wasps are sometimes a big problem on bluebird trails.

I suspect the problem for the western bluebird is something like one of these ideas though. I wonder if the western is unique in that it stays on its range all year? Less migration than the other two species? Just a thought.

Bernie

Keith Kridler Mt. Pleasant, Texas
I pulled out an old flying squirrel nest yesterday and got covered with fleas. Tossed the old nest, nestbox and pole in the swamp for a couple of hours. The squirrel nest was made out of Eastern Red cedar bark strips! SO MUCH for the insecticidal qualities of red cedar!

Mountain bluebirds normally nest at higher elevations than the Western Bluebird but both can and will use most nestboxes with a 1&1/2" entrance hole. Only "some" Mountain Bluebirds need the 1&9/16" round entrance hole but ALL bluebirds can benefit from a slightly larger round hole that will
exclude the European Starling.

Since bluebirds have to enter the hole many times a day a "rough cut" 1&1/2" hole will wear the shoulder and wing feathers on all three species of bluebirds to some degree. Jack Finch in North Carolina has made 190,000 Eastern bluebird nestboxes with the 1&9/16" round hole with no known
Starlings nesting. I have used the 1&9/16 for twenty years or so now supposedly to help out the Great Crested Flycatchers.

The Gilwood nestbox with the wire running through the large hole WILL NOT stop European Starlings from entering this nestbox or reaching into this box. Grackles in the east and Magpies (in the western states) can and do reach into nestboxes to pull out young cavity nesting birds for food. The
larger the hole, the shallower the nestbox, the easier it is for predators to raid a nestbox!

There have always been more and bigger Eastern Bluebird trails maintained for far more years in one location or really a whole region. Mountain Bluebird trails started out with fledging just a few Mountain Bluebirds. Then with HUGE trails with tens of thousands of nestboxes they have begun to
really increase the Mountain bluebird populations adding young by the tens of thousands over thousands of square miles of connected trails each year.

You cannot compare these efforts with relatively small or young trails in borderline habitat for the Western Bluebirds. California and much of the southwest experiences brush fires every year or so that prevents the growth of future cavity producing trees. Forest fires in remote areas in mature
timber create snags for trees swallows and woodpeckers in areas most people don't go to for years after a severe burn.

Woodpeckers will flock to forested regions infested with pine bark beetles and sections were trees are dying by the thousands due to oak wilt and other diseases or to regions where there has been fire. Once again these are usually in remote forested areas well away from suburban trails or even
roads. Secondary cavity nesters follow the hammering of woodpeckers or really the cavities they produce.

Western bluebird habitat I would believe has historically been very open semi-desert. West Texas (most of the southwest) historically burned every year or at the most every 30 years which left only a few larger trees immune to damage from grass fires per acre. In scrub land birds would have almost
no protection from "bird feeding" hawks. Many natural cavities would not exclude the small owls that would feed on cavity nesters. Protecting land from fire also removes the short and tall prairie grasses replacing them with brush altering the habitat these birds evolved with.

I doubt any one issue actually adds up to keeping the population of Western Bluebirds in slight decline but where people are, there are now threats of house sparrows and starlings, cats and rats. Bird feeders increase chipmunks and squirrels, jays, magpies and grackles thrive around humans, their landscaping and their food dumps all are predators of birds.

LOOK to see where Christmas Bird Counts and Breeding Bird counts are tabulated in California and you will probably see whole regions of good natural habitat for the Western Species of Bluebirds where NO ONE is looking for them. Pull up maps of forest fire burn areas for the past 6 years in
mature timber and take a trip to this region to count cavities.

Don't look for Eastern Bluebirds in Downtown Chicago or in the middle of a 10,000 acre corn field. Know the habitat of the birds you want to attract or see and look in those areas. KK

Bernie have you run an analyis of the number of nestboxes per square mile in E vs. W? Although I guess that wouldn't tell you how many nestboxes per square mile of suitable bluebird habitat you have...

Do Western bluebirds have a similar home range as Eastern bluebirds, or is it larger?

From: lviolett [mailto:lviolett"at"earthlink.net]
Sent: Wednesday, March 30, 2005 2:05 AM
Subject: Re: Concerns about Western Bluebirds.

Linda Violett - Yorba Linda (urban trail) and Big Bear (mountain trail), Calif.

As to why the Western Bluebird population isn't rebounding as dramatically as the Eastern and Mountain Bluebird population, I'd venture to say the two foremost causes are:
1) Loss of habitat (actual destruction of natural habitat), and
2) People pressures (pets/cats, poisons, HOSP feeders/boxes, rats attracted to feeders/boxes, pollution and vandals)

Some are suggesting that more nestboxes are needed to help the Western Bluebird populations rebound. This year I have had to remove some boxes from the urban trail because the last "wild" spaces are being bulldozed. The urban trail consists of boxes placed in heavily used urban areas such as parks, schools, and a golf course. Those open spaces are finite, regardless of how many more nestboxes are built.

It is doubtful that Mountain Bluebirds are putting any pressure on Westerns where they overlap. My mountain trail in Big Bear (altitude at about 7,000 feet) has both WEBL and MOBL in the area and either species could use the boxes because they have 1 9/16" holes. Western Bluebirds, but not Mountain Bluebirds, have nested on the trail. Interestingly, the only real problem on the mountain trail is people dumping seed which brings HOSP right up to the edge of the forest. It will be interesting to watch the Mountain/Eastern population trends over the next 20 years as those habitats/trails are urbanized.

No, I really do not thing this is a "development" matter. It's not the primary reason anyway.

What is probably "wrong" about suggesting habitat loss is the simple fact that, by far, the range of the eastern bluebird is much more urbanized and developed than the western range right now -- as we speak.

So the development argument seems to be dead on arrival to me because if you list all the traditional "pressures" that we tend to conjure up for bluebirds/bluebirding: sparrows, urbanization, row crop ag etc etc. are more prevalent here it the east than you deal with in most of the west -- California perhaps the exception.

You can look on any recent satellite imagery of North America to confirm the urbanization part of it. And surveys show sparrows and starlings are still much denser in the east than in the west. In fact, over most of the western's range -- except for central California house sparrows are much less prevalent than we deal with on our eastern bluebird trails.

Here is a specific example of the "problem". The USGS Biological Survey and the Partners In Flight world-wide assessment both show that the a sizable percentage of the total Continental western bluebird population lives and breeds in an area centered on the "Four-Corners" region (where AR, NM, UT, and CO intersect). Now that area is NOT a hot bed of development and there are large tracts of undeveloped areas including several Indian reservations. There are no large towns within a hundred miles. Still the western bluebird does not seem to be increasing even in that area.

No, I do not think it is habitat loss is the main issue -- although development certainly does not help.

But, as an aside, I cannot imagine what development you would be waiting for on the eastern bluebird's range, Linda. (smile).

This part of the country has been "developed" for centuries. In fact, by the time Rutherford B. Hayes left Ohio for Washington, in 1877, to serve as our 19th president ,the Great Black Swamp -- which had covered the northwestern corner of the State was already drained. The vast majority of the gallery forests were stripped from Ohio BEFORE the Civil War.

No, we do not need to wait to see development in the east. In fact, that's the whole point here -- even as the eastern US has continued to develop eastern bluebird numbers have continued to increase. And that is the whole reason for my concern (and obviously also the concern of North American scientists who deal in avian management).

In fact, the only basis I have to raise this issue in the first place are these continental surveys and projections.

My 2 cents worth (based on 1960's values and worth one small whiff of gas fumes today)

Bernie

I fervently hope we do not give up on trying to figure this out, sticky wicket though it might be. There MUST be a reason(s).

I'm inclined to think a key factor is number of monitored/maintained nestboxes.

I don't know whether individual boxes spread out vs. substantial trails makes a difference in populations.

Also wondering if there is more pesticide use out west that maybe impacts food supplies/survival.

Has a study been done of productivity per nestbox that would indicate any significant difference there of eastern vs western?

Is there any indication that western bluebirds prefer natural cavities and aren't as likely to use nestboxes and thus may suffer more predation?

Are there any disease issues that are different for eastern/western.

Has bird banding data provided any info on longevity - maybe westerns are not living as long so don't have as many years to repopulate?

To me the key is the DIFFERENCE - to explain why eastern pops are recovering and western are not.

Just brainstorming here - I think we have to be open to all the possibilities....

From: lviolett [mailto:lviolett"at"earthlink.net]
Sent: Saturday, April 02, 2005 3:10 AM
Subject: Re: Concerns about Western Bluebirds.

Linda Violett - Yorba Linda, Calif.

Bernie, states that he does not believe loss of habitat/urbanization is a major factor of the Western Bluebird's decline. He adds, " . . . I cannot imagine what development you would be waiting for on the eastern bluebird's range, Linda. (smile)."

If you flip through the Bluebird Monitor's Guide and look at the pictures of eastern nestbox trails, they are located in what appears to be rural or semi-rural habitat. Then flip to page 67 of the Bluebird Monitor's Guide to see a nestbox trail in developed/urbanized habitat. See any difference? That difference may be the key as to why the Western Bluebird population is in decline and the Eastern Bluebird population is still increasing.

Again, it will be interesting to watch the Mountain/Eastern population trends over the next 20 years as those habitats/trails are urbanized.

Linda,

I'm not sure we are living in the same North America. I'm in the one in the WESTERN Hemisphere (smile).

I HOPE that you do not think the level of development across the entire North American continent can be deduced by looking at a couple of random photographs that happen to appear in the Bluebird Monitor's Guide?????? It seems like you do???.

I'm sure that you noticed that Lake Erie and the Grand Canyon were not shown in the Bluebird Monitor's Guide Book either. Indeed they are not. But I can assure you that both still exist anyway.

The point is that you should realize that a few photos in a book designed to show ideal bluebird habitat MIGHT not represent the land cover status of the entire Continent? (Smile).

Think what you wish. But I'm only interested in REAL evidence relating to this matter. I know of no physical measure that could be used to demonstrate that is the western North America more developed than the eastern part -- and frankly you are the first person I have ever heard even suggest such a thing.

The reason for this is pretty straightforward isn't it -- as you know -- the Mayflower landed in Plymouth not Santa Barbara right?

You can continue to suggest that you are waiting for development to happen on the eastern bluebird range if you wish -- but those of us who live here know that much development has already happened and that much of eastern North America and most of the eastern's bluebird's range is in developed areas already.

Now I repeat -- It is a simple, easily proven FACT that range of the eastern bluebird is generally located on a more developed part of the Continent -- overall than the western bluebird's range -- ALREADY. We do not need to wait.

So to argue development main cause of the western bluebird's troubled status -- a priori -- is illogical in my opinion. That said development may be PART of the problem -- but I think something else more important -- is going on.

You know, being stubborn on a point is OK but only TO a point -- but at least you could take the time to provide some objective evidence and some rational for your opinions -- eh?

Bernie

From: lviolett [mailto:lviolett "at"earthlink.net]
Sent: Tuesday, April 05, 2005 3:29 AM
Subject: Re: Concerns about Western Bluebirds.

Linda Violett - Yorba Linda, Calif.

Shame on Bernie for the coarse response to a perspective he did not want to hear regarding possibilities of why the Western Bluebird is still in decline.

On my trail and many other Western Bluebird trails in Southern California, nestboxes cannot be mounted on posts; they must be hoisted up into trees. Why? It isn't done to get the boxes above wildlife; it is done to get nestboxes out of the way of people. This unique method of monitoring trails is normal for nestbox trails in Orange County. The fact that most eastern trails can be mounted on posts is an indication that those trails do not have the degree of urbanization that we are experiencing here on the Western Coast. Therefore, if I were compiling a list of possibilities to discover the source of population variance trends between the eastern/mountain/western species, you can be sure that habitat loss and people pressures would be included in *my* list of possibilities. It goes without saying that there was no obligation on my part to offer the suggestion and Bernie has absolutely no obligation to include habitat loss and people pressure as a possible answer.

Here is an interesting quote by Gerald Durrell, Nature Conservancy:
“You cannot begin to preserve any species of animal unless you preserve the habitat in which it dwells. Disturb or destroy that habitat and you will exterminate the species as surely as if you had shot it. So conservation means that have to preserve forest and grassland, river and lake, even the sea itself. This is vital not only for the preservation of animal life generally, but for the future existence of man himself—a point that seems to escape many people.”
---- Gerald Durrell,
Nature Conservancy

From: Chuck Jensen [mailto:cjensen "at"dts9000.com]
Sent: Tuesday, April 05, 2005 8:58 AM
Subject: RE: Concerns about Western Bluebirds.

Ms. Violett,

Quoting a person, who is expressing a certain viewpoint and whose statement is loaded with generalizations and opinions, is hardly probative or definitive in proving a point. In Mr. Durrell's case, his profession and employer pre-discloses his position on the matter...I could have guessed what he would say before he said it. Now, that doesn't make what he says wrong, but it certainly doesn't make it right either. In short, while, in a very general sense I agree with what he says, I find not a scintilla of fact, data or evidence to support his hypothesis. Because it is intuitive (and reinforces our beliefs and prejudices) does not make it correct or right.

I know little about the matter (which puts me on equal footing with many others, including some on this list) but it seems urbanization is likely less harmful then loss of habitat (though the two are interrelated). I see suburban areas with a robust population of Bluebirds and other rural areas with few. Both environs would benefit from a well constructed and monitored trail (that's for Evelyn's sake) but its just more difficult to do in a suburban setting than in a rural area.

I'm concerned about blaming the decline of the WBB on "population sprawl" of which we can do little or nothing, unless we want to implement the China model of sterilizing women after the first birth. On the other hand, constructive consideration of the benefits that can be wrought with the creation of artificial habitat to counteract the negative affects of urbanization (if there are any) and study of why the WBB hasn't responded to efforts to increase their populations like the Eastern BB, or whether these efforts have even been made, seems more productive. Perhaps more intense education and training of people/groups in the West to mimic successful efforts in the East would reverse the problem. Or, we could wait for the Big One and half of California will slide off into the Pacific anyhow, so it won't matter.

Lots of interesting avenues to pursue rather than just blaming urban sprawl, of which we can do nothing.

Chuck

From: Bernie Daniel [mailto:bdaniel "at"cinci.rr.com]
Sent: Tuesday, April 05, 2005 9:34 AM
Subject: Re: Concerns about Western Bluebirds.

Maybe my response was "grumpy". It is not my intention to offend anyone.

But you seem to want see the entire world as an extension of your own neighborhood and that is not necessarily a way to deal with this problem.

Most western bluebird habitat, in fact more than 90% of it, is NOT located in Orange Co., CA (a place I am well familiar with as I have been a scientific advsior to the Orange Co. Water District for many years and get there several times a year).

So what is happening in your back yard might well be of interest to you and your neighbors and important for the LOCAL western bluebird populations. And it is certainly of general interest to other bluebirders too.

HOWEVER, it probably has NOT TOO MUCH to do with the OVERALL issue of what is happening to the western bluebird across the entire western half of the North American Continent. That's the point I was trying to make to you.

You cannot look in a few pictures in a Bluebird Monitor's guide and then make sweeping statements about the plight of an entire species across its entire range.

Nowhere did I say habitat loss had nothing to do with the problem. I said given that MOST of the western bluebird habitat is in areas of the of the United States that is NOT nearly as heavily developed as the eastern US that development does not seem to be the PRIMARY problem -- its something else.

If you have some evidence for that habitat loss is the major problem then present it but the scientists who have studied this matter do not seem to agree with you.

One of the largest tracts of western bluebird range is in on the Navaho Nation Indian reservation northwest of Santa Fe, NM. Would you say that is a highly developed area with degradation of habitat Linda?

Another major area of western bluebird range is to the west of that and south of the Grand Canyon on the Coconino Plateau and west of the Kaibab Naitonal Forest -- not exactly a hotbed of development either is it?

Yet in neither of those two places are we seeing obvious the expansions of western bluebird numbers. WHY? I do not know but for sure it does not seem to be habitat loss!

You state: "Therefore, if I were compiling a list of possibilities to discover the source of population variance trends between the eastern/mountain/western species, you can be sure that habitat loss and people pressures would be included in *my* list of possibilities."

I have a suggestion for you, Linda. Why don't you actually compile such a list before speaking ex cathedra about this topic? I have been collecting data. There is scientific data accumulating on this topic of the western bluebird -- I suggest that you look into it.

If you actually make a study into the amount of development of the ranges of the eastern and westen bluebirds you might have a basis for your opinion. If you have not studied the matter why are you insisting that you know the answer?

I have not interest in arguing on a list server about this topic. Instead, I am interested finding out what is going on on the ground in the western bluebird range. You have supplied some information on Orange Co. what about the rest of the range?

It sounds like you have some habitat problems where you happen to live in Orange Co. However, I have seen several trails in that area where bluebird boxes are mounted on poles.

Maybe development is a problem or even the problem in Orange Co. CA but that is not the main problem that the western bluebird is facing. In any case the development is much greater on the eastern bluebird range and it is experiencing modest INCREASES in its numbers across its range.

QED!!

Bernie

From: charlene anchor [mailto:charleneanchor "at"msn.com]
Sent: Wednesday, April 06, 2005 10:45 AM
Subject: Birds of North America and the Western Bluebird

Just recently I discovered "Birds of North America" on-line. BNA has been a 10-year project which was completed in 2002. It is the species accounts of ALL the birds of North America consisting of 18 volumes and 18,000 pages. Cornell Lab was involved in this long 10-yr study and has now enabled it to be put on-line. There is a subscription price of $40 per year, maybe too much if one only wants to look up a bird or two. But it's a great bargain for continual reference for multiple species or even if one wants to do thorough research on just a few. I believe there was only a limited number of sets printed at a very costly price to the purchaser in the range of $1800, or possibly more!

If anyone wants to read the scientific studies done so far on the Western Bluebird, this is where the references to do so can be found. If Bernie, or anyone else, is serious about digging into some of the questions that have been raised, check this out! The accounts given are very thorough even without looking up the references and would give one a beginning. The account of the Western Bluebird is based on 158 references from 1904 to 1998.

The following info is given under the "management" heading: Habitat degradation most likely is the most important contribution to declines in Western Bluebird population. Expansion of residential and industrial areas, fire suppression, clear-cutting, snag removal, and changes in agricultural practices have all led to a decline in suitable areas for breeding and foraging. Direct competition from HOSP and the starling may have been a factor in decline in more settled regions. In Washington, declines also attributed in part to regional climatic changes after 1940 as increases in wet weather led to a decline in prey abundance.

Past population trends in the various areas are discussed. These are mostly based on the Breeding Bird Survey. The BBS has it's limitations and since almost 50% of the BBS data is from California, California's declines greatly influence the trend data. So it turns out that the REAL population status is not fully understood. Another thing stated is "Knowledge is sparse on many aspects of WEBL demography, physiology, ecology and behavior. An immediate priority is to accurately determine trends in local abundance throughout the range of the species to resolve whether action is required to assure its conservation."

Something else I thought was interesting was that nest boxes were referred to as a "viable short-term solution" until natural habitats with sufficient nesting sites are available. Interesting also is that long-term measures have been proposed and some have already been adapted for increasing natural habitats which involve management of natural areas. They also mention that the effects of extensive use of nest boxes on the local species composition has to be studied more as they may have a negative impact on local species composition.

It appears that, as in all aspects of nature where many factors are involved, that there is no one simple answer. It's easier to arrive at a conclusion with limited data but much more difficult when trying to look at the entire picture. This website can provide a more accurate picture of what is, or is not happening, as well as what is, or is not known.

For a demo of the website go to: http://bna.birds.cornell.edu/BNA/
Charlene Anchor, Central Illinois

From: Elizabeth Zimmerman [mailto:ezdz "at"charter.net]
Sent: Wednesday, April 06, 2005 5:20 PM
Subject: RE: Concerns about Western Bluebirds.

When I look at the history of the Eastern bluebird and population impacts over time, the factors that have been implicated as significant are:

- severe weather (especially late spring freezes)
- introduction of house sparrows and starlings
- loss of open space (especially open areas vs. forests)
- pesticide use
- loss of snags (dead trees)

and to a lesser degree:
- transition from wooden fence posts to metal
- use (and then discontinuation of) tobacco barn heaters (birds trapped in vent pipes)

and on the positive side:
- education about bluebird conservation
- installation of nestboxes

I still think the key is determining WHICH of these is DIFFERENT for the EABL vs the WEBL
AND
what OTHER factors might be at play (e.g., disease, productivity by species, etc.)

Maybe there are more nestbox vandals in CA that there are in the East... I don't know the answer to that one. I just know there seem to be plenty of hooligans in my neighborhood :-). And in my state at least, loss of open space is a growing and dramatic problem...but the bluebird population continues to steadily increase.

Bet from CT

From: Bernie Daniel [mailto:bdaniel "at"cinci.rr.com]
Sent: Thursday, April 07, 2005 12:04 AM
Subject: Re: Concerns about Western Bluebirds.

Bet

Great Post!

I think you have proposed a nice logic framework for thinking about this problem. This is the idea break the problem up in to bit size pieces and then chew on the one at a time. Many of these elements are things that I have wondered about too. Starting wth your list. -- your points in teal (or blue-green) mine responses in black.

- severe weather (especially late spring freezes) -- this IS a frequent problem for our EABL for sure -- it comes sporadically fortunately as we all know -- but especially wet/cold springs can be really tough -- on occasion -- over most of the EABL range. It is also a problem for MOBL over much of its range it is probably even a more frequent problem in states like MT, CO, WY then it is for us in the most of the east. I am thinking it MIGHT be LESS of a problem over most of the WEBL range -- but this is something that western bluebirders can comment on. On the other hand, I wonder if DROUGHT is a more typical problem of those bluebirders trying to help WEBL? Much of the west has been in drought for nealy a decade. Again we can ask this and we can examine it by looking at weather trends over various periods -- and over various areas (and/or bird ranges). Using the North American Breeding Bird Survey data base we can examine specific periods of time for estimates of WEBL status (and/or production) versus prevailing weather patterns.

- introduction of house sparrows and starlings -- again the HISTORICALLY has been more of a problem for those of us raising EABL because both exotics were released on the east coast (in circa 1860 and 1890). I plan (one of these days) to overlay the densities of these two exotics over the extent of the WEBL and EABL ranges when I finish updating my GIS data base with the 2004 data.

- loss of open space (especially open areas vs. forests) -- Ditto. Historically the east was developed first and overall is still more developed that the west. But times change. The counter argument might be as I've noted much of the WEBL range is in fairly Undeveloped areas BUT the hitch might be that in these area we do not have enough bluebirders. Maybe a large percentage of western bluebirders live in developed area like Linda is talking about where they ARE fighting development and habitat loss? If that is the case, then there is at least a partial solution i.e., let's get nest boxes up in these undeveloped areas! We need to prove this -- BUT I think over most of the WEBL the habitat is less developed (in better shape) that for the EABL.

- pesticide use -- I really do not see this one as being a "biggy" -- not to say it has NO impact but most pesticides these days are herbicides -- very low toxicity to vertebrates. Again over the California parts of the WEBL range lots of insecticides and other compounds for invertebrates are indeed used. But maybe not over the bulk of the WEBL range?

- loss of snags (dead trees) -- another one to ponder -- is it "inter-linked with the one on exotic species? In the east I often wonder how much snags matter to bluebirds any more. In years of bluebirding and birding in general I have seen a total of 1 bluebird nesting in a natural cavity in Ohio! Do Bluebirds get any significant percentage of natural cavities anymore? Or are they all taken up by starlings and sparrows. How important are snags and natural cavities in the WEBL range compared to the EABL or the MOBL? Good question!

transition from wooden fence posts to metal -- like the others we need to understand if this matter varies between the three species habitats. But is a good point to think about.

- use (and then discontinuation of) tobacco barn heaters (birds trapped in vent pipes) -- obviously an eastern US problem but is their a western analog to this probem?

Your quote: "And in my state at least, loss of open space is a growing and dramatic problem...but the bluebird population continues to steadily increase"

I agree strongly with this -- Ohio is the same way we are indeed certainly losing EABL habiat each year to development -- but I think our efforts have provided a strong enough nest box infrastructure that can at "least tread water" and in addition I think we continue to make more efficient use of the habitat that we have left -- via improving our craft and via education outreach to our various state members. Perhaps something like this is the key to understanding the WEBL problem

One other suggestion -- perhaps we will make faste progress in understanding the WEBL problem by comparing it to what is happening with the MOBL rather than the EABL -- they are both on westen side of the Continent.

Bernie

From: Bernie Daniel [mailto:bdaniel "at"cinci.rr.com]
Sent: Thursday, April 07, 2005 12:33 AM
Subject: Some Actual Numbers on Continential Bluebird Population Trends

All

Perhaps I have not done a good job in framing this issue. Please take a look at this.

Here is a table that I put together last year. It was created using Continental-wide
North American Breeding Bird data for the three bluebird species.

The overall trend for both MOBL and EABL is positive -- for example a
trend of 2.75 for EABL is a good finding.

This means a 2.75% percent increase per year for EABL.
Certainly that is a very NICE number to see. What's more the number is
statistically significant. Very significant.

The p-value < 0.001 means that there is less than one chance in
thousand that this number occurred by chance. That is if you get a result like this for
EABL more than 999 times out of 1000 it will be a "real" effect.

Since 1966 we have increased the numbers of EABL in spite of development.

For MOBL the increase is 1.65% per year and the p-value indicates that about 149 times
out of 150 these numbers would be to a real change in WEBL number and NOT due to chance.
Rather it is almost certainly a real trend -- but we are a bit less certain than we are for
EABL.

As you can see WEBL are DECREASING at about 1% per year. The high p-value means that
we are not really sure this is happening --that is we do not know for sure what the WEBL is
doing over its range --but wouldn't you agree this is not a hopeful result?

The reason for the high p-value is probably lack of enough data -- notice only about 283 BBS
routes report WEBL every year and over 2000 have EABL -- on one of my BBS routes
in extreme southern Ohio (Adams and Brown Counties) I typically see 12 - 20 EABL over the 25
mile survey route.

Perhaps this helps frame the issue that I see as regards these three species.

Bernie

From: Chuck Jensen [mailto:cjensen "at"dts9000.com]
Sent: Thursday, April 07, 2005 10:22 AM
Subject: RE: Some Actual Numbers on Continential Bluebird Population Trends

Bernie,

Excellent posts. We all benefit from data and facts. Science trumps conjecture, anecdotal observations and subjective opinions every time.

Looking at your data, my subjective opinion is that development and loss of habitat for the EABL has been readily, if not easily, overcome by provision of artificial habitat--that can actually be an improvement over natural habit if it is well maintained (learned from one of Evelyn's presentations).

Another way of looking at the impact of human intervention is if we have a 10 acre natural site that supports 10 EABL and it gets bulldozed and 100 people move into the new houses, then we have lost 10 EABL. However, among those 100 people, it turns out that two of the residents happen to like Blue Birding and put up a couple trails, one with 6 and the other with 5 EABL, for a total of 11 EABL...a net increase of 10%. Stay with me here.

Now, if we carry this to its logical conclusion, then we can see that to increase EABL, we need more development and natural habitat destruction.

I rest my case.

Chuck

From: Evelyn Cooper [mailto:emcooper "at"bayou.com]
Sent: Thursday, April 07, 2005 10:33 AM
Subject: RE: Some Actual Numbers on Continential Bluebird Population Trends

Chuck Jensen wrote:

"Now, if we carry this to its logical conclusion, then we can see that to increase EABL, we need more development and natural habitat destruction."

To me, this is an absurd conclusion. To not consider all the other native cavity nesters that our MISSION STATEMENT supports, is way out of line. I would not ever recommend such a statement.

It also affects other wildlife too, which I don't have to point out. Let's be reasonable here.

Evelyn

"Now, if we carry this to its logical conclusion, then we can see that to increase EABL, we need more development and natural habitat destruction."

Yes lets carry this to the full extent...........You have more people who put up boxes, and suppose they don't put them on poles with baffles, do not take care of them, let HOSP take over, nor monitor them, have pets ex: cats which that is a whole other discussion.....Plant non native plants, etc..........

that statement is a shocker for sure...........

Crystal~Georgia

Crystal, Chuck was advocating *more* habitat distruction, and I don't think that is what you mean.

He wrote to me that it was a *joke*, but you see, you took it seriously and did not really get the meaning of his statement. I don't think you or anyone else wants to see *MORE* of our habitat destroyed, not only for EABL but for other wildlife that needs it so desperately.

Evelyn Cooper
Delhi, LA
Louisiana Bayou Bluebird Society

From: Chuck Jensen [mailto:cjensen "at"dts9000.com]
Sent: Thursday, April 07, 2005 11:05 AM
Subject: RE: Some Actual Numbers on Continential Bluebird Population Trends

Okay, I get it...many did not get it and so that newbies, that apparently wouldn't know better, can be assured that:

1. Habitat destruction is NOT good
2. Building more people-houses is NOT good
3. 2&3 above are NOT a good methods of increasing EABL populations
4. I hereby resolve to not employ facetiousness as a means of illustrating a point or provoking thought
5. I shall hereby limit my postings to:
a. how many new eggs I have
b. how I hate HOSP

In the interest of full confession and contriteness, I admit I am not a good fit for this Forum that is dedicated solely to Blue Birds and not extraneous issues, like insightful facts and thoughtfulness. As such, I retract number 5 and I unsubscribe.

Chuck

From: mrtony8 [mailto:mrtony8 "at"cox.net]
Sent: Thursday, April 07, 2005 12:43 PM
Subject: Re: Some Actual Numbers on Continential Bluebird Population Trends

Yes, provided you can convince more people to become interested in putting up boxes, which is precisely what most of us do.
Phil Berry

From: Bernie Daniel [mailto:bdaniel "at"cinci.rr.com]
Sent: Friday, April 08, 2005 6:32 AM
Subject: Re: Some Actual Numbers on Continential Bluebird Population Trends

Chuck,

I agree with you. I think your comment is insightful --- you state that::

"Looking at your data, my subjective opinion is that development and loss of
habitat for the EABL has been readily, if not easily, overcome by provision
of artificial habitat--that can actually be an improvement over natural
habit if it is well maintained (learned from one of Evelyn's
presentations)."

This is a good way of stating the matter.

We ARE seeing a loss of prime habit everywhere in the North American
Continent as the population continues to grow. But with the EABL -- as a result of some inspired folks 50 years ago -- including D. Zeleny and others --we have used human energy and creativity to offset this loss of natural habitat. I think we got lucky with the EABL (and other cavity nesters) its easier to build a Bluebird trail than it is to create 50 - 100 acre tract of mature forest for Scarlet Tanagers for example. But we need to keep trying.

Ditto the MOBL -- it seems to be definitely increasing across its range -- human energy and will is providing a habitat infrastructure that is supporting the species.

We SHOULD be able the help the WEBL like the other two -- certainly many are working very hard
to grow that population but so far it does not SEEM to be working as well as the other two species.
Let's try to find out why and THEN figure out what we can do about it.

Bernie

From: Bernie Daniel [mailto:bdaniel "at"cinci.rr.com]
Sent: Friday, April 08, 2005 6:10 PM
Subject: Breakdown of Western Bluebird Trends

More on this.   In the previous note I presented a table showing how the BBS data indicates that, unlike the other two Bluebird species, the Westeren has (apparently) not responded as effectively to our efforts. Here then is a breakdown of WEBL trends over the period of 1966 to 2002. The purpose of this table is merely to show the basis for the concern that various national bird managing programs have reached with regard to this species.  If you look an up-to-date range map of the WEBL you will essentially see (in my opinion) three "population" centers.  Take a look at this BBS map:    link to map: http://www.mbr-pwrc.usgs.gov/bbs/htm03/ra2003_red/ra07670.htm These are Range #1 Western Calfornia, Range #2 the Utah, Arizona, New Mexico, Colorado (Four Corners) intersction, and Range #3 a smaller center located in Washington and Oregon.  Western are mostly a USA issue with only a small bit or range in Canada. Also Range #3 (WA-OR) is kind of "attached" to the Range #1, California center. (I have NO idea how much interchange goes on between birds of these three centers -- and right -- these are just geographical locations thats all).  But here is  break down of the WEBL population trend by region:

Now again notice that no matter where you go in the WEBL range the trend (change in population per year by percent) is NEGATIVE that is DECREASING. This suggests that we are losing this fight. Also note however, that none of these estimates are statistically significant  -- so they could be wrong.  But right or wrong I would like to see the numbers going the other direction!!! Now as to causes.  We have considered different things on this forum.  This one table will not solve all of  our problems but notice that the area with probably the most development (CA) has the best population trend -- there the numbers show a near b  r  eak even status. Then look at the least developed area --the Four Corners -- here the trend is the worst 5% loss per year!  As I said I do not think this is simply a "development/loss of habitat" issue.  The California Bluebirders are working hard they are producing many fledglings - where are they going?  Why aren't the numbers on Range #1 going up?  I do not understand it.  Is California a "source" of WEBL that are then bleeding off into some "sink" somewhere?  If so where? I am starting to think it is a partly "logistics" problem.  Do we have viable Bluebirding programs across the entire WEBL range?  You folks living out there know better than I. For example, do we have enough Bluebirds in the Four-Corners area?  Who could shed some light on this?  Many Native Americans live in this region.  They are by tradition attached to earth-wildlife issues.  Do we have efforts to engage native Americans in the Bluebird movement?  Are they already engaged?  If not can we do something along these lines.  Or am I barking up the wrong tree? Bernie

From: Bernie Daniel [mailto:bdaniel "at"cinci.rr.com]
Sent: Saturday, April 09, 2005 2:44 PM
Subject: Western Bluebird Trends __ Still More

OK -- I've reorganized the data base and started the in-depth analysis of WEBL and somethings are starting to pop out -- maybe.

The BBS database for Bluebirds alone is over 38,000 rows times about 25 columns of data (= 950,000 cells of data). It adds up and it takes a while to be sure that you have what you think you have in the analysis.

1) If someone can advise how to do it I will display for you some graphs of WEBL detected per year on the BBS by "Western Bluebird Range"

2) Western Bluebird Range is a spatial convention that I have created as a tool to deal with the data and break it down into pieces and also to represent the various sections of the North America that WEBL breed -- these regions are different. Here they are:

Western Bluebird Range -- West = California and Nevada
Western Bluebird Range -- North = Washington, Oregon, Idaho, Montana, British Columbia, and Alberta
Western Bluebird Range -- South = Utah, Colorado, Arizona, New Mexico and Wyoming

3) The year average number of WEBL detected per route is plotted against year.

For a minute lets just consider the Western Range:

It is interesting -- in the Western Range things seemed to be at least in a steady holding pattern from 1966 to about 1995. Over this period about 8 WEBL were detected (average) per route every year.

Then after 1995 things go real erratic with the number of WEBL/route going up and down sharply from year to year but in general being significantly below the period of pre-1966 (ranging down as low as 4 WEBL per route) in years like 1998, 1999 & 2003.

OK, you in California & Nevada what happened during this time? Linda has earlier said development and loss of habitat is the reason. Maybe this is indeed PART of it -- was there a huge increase in development in this part of the country after 1995?

Or what about the climate? When did the current western drought start? How widespread was it? Would a WEBL crash after 1995 be consistent for the drought that is going on?

The answer to this question would be best addressed by review climate data -- but for now what do you Bluebirders from CA and NV think? Does this make sense?

I will post these plots if we have a way to do it -- they are just jpg's of Excel files so they are small in terms of bytes.

Bernie

In one of your posts on nestboxes in HOSP (house sparrow) populations, you noted "Are there more bluebirds in North America now than there were in 1600?"

Of course we have no data on this, but according to early reports, at one time bluebirds may have been as common as the American robin. Populations have been affected by many factors, some of which had both positive and negative impacts. For example, tree clearing created better hunting habitat, but clear cutting removed nesting snags. Prior to 1941, very little population data on bluebirds is available. The Audubon Society's Christmas Bird Count (CBC) from 1941-2003 for the U.S. seems to indicate that EASTERN bluebird populations bottomed out in the 60's and 70's, and since then have been steadily climbing, I think in response to conservation efforts (putting up nestboxes etc.)

On the other hand, some folks posit that HOSP populations peaked in the early 1900s. When automobiles and farm machinery replaced horses and farm animals, the HOSPs primary source of food was reduced.

There is research evidence that HOSP populations are declining in Europe, but last I looked, no one has yet determined why. Breeding Bird Survey data also indicate that the population is declining in the Maritime provinces and in the eastern and central United States. Possible reasons that have been proposed are changing agricultural practices such as a shift to monoculture crop plantings and sealing grain stores to reduce access and spillage; increased pollution; use of herbicides/pesticides (and its impact on food sources - HOSP nestlings are exclusively fed invertebrates for the first four days of their life); destruction and/or damage of natural habitats; loss of nest sites; feral cat and hawk predation; and starvation or infection.

However, with the proliferation of fast food restaurants and stores such as Home Depot (with an almost endless supply of bird seed, water and nesting areas), and homeowners who feed inexpensive bird seed mixes containing millet and cracked corn, house sparrows continue to be ubiquitous in the U.S.

More info on the bluebird history (draft) is at http://www.sialis.org/history.htm and on HOSP at http://www.sialis.org/hosphistory.htm
Input, corrections, etc. are always welcome!

Bet from CT

To add to your list of reasons for HOSP--I can think of some. People! They
throw out food at their homes instead of trashing it. Dumpsters at grocery
stores, etc. and concession stands at schools, etc. It would be impossible
to correct these practices. I have become more diligent in noticing our
behaviors that influence nature. We should all be aware of bad practices
and try to think in light of our envioronment--which proves to be the point
of many folks trying to save our environment. Thanks to dedicated birders
like you all there might be a change in the future. Linda in NW GA

From: Dick Stauffer [mailto:sapl"at"agt.net]
Sent: Friday, July 29, 2005 10:50 AM
Subject: populations

Hello all:

Does anyone out there know what the estimated populations are for
Mountain Bluebirds
Eastern Bluebirds
Western Bluebirds
Tree swallows

Thanks,

Dick Stauffer

Keith Kridler Mt. Pleasant, Texas
Great posts this morning from Bill and Torrey! WOW one pair of bluebirds raising 19 young in a single year is amazing! I had a box one year that raised 3 broods of 6 each that fledged. Below is a link to a webpage for Mourning Doves that says they often lay five or six clutches of eggs each year and from these they normally raise only 5 or 6 young to fledge at day
11>14. Have you seen the pitiful nests these Doves build? You can
11>normally count the 2 or 3 eggs balanced on a handful of sticks from under the nest!

http://msucares.com/pubs/infosheets/is630.htm

Anyway they say that in a normal year there are 475 MILLION doves alive every fall and that doves like quail will lose about 70% of their fall population by next breeding season so the roughly 100 million surviving doves will again populate North America and their southern migration areas to over flowing. If you read the article it mentions just one disease that kills them by starvation but there are many other diseases that are fatal.
Dove season opened across the south in many areas on Sept. 1. Texas has placed the Eurasian Collared Dove on the pest species list and they encourage all hunters to take advantage of no limit or no closed season on this Dove that is common now in East Texas.

The advantage that bluebirds and chickadees/titmice have is that they stay together as a family group and learn where the winter foods are that their parents relied on last year. They have extra eyes to watch out for predators in a family group and can learn what is dangerous or not without having to feel the claws first hand! KK

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