Nest abandonment (Part 3)

Also see Clean Nest or Abandoned?

From: Tyler Mann [mailto:t_mann05"at"hotmail.com]
Sent: Friday, May 27, 2005 11:50 PM
Subject: HELP! Question with fostering abandoned TRES eggs Hi all

As you may have read before, i had a female TRES disappear and leave 4 eggs.
The Male is still around though. The eggs were on day 8 of the incubation cycle. I have another complete TRES nest with 6 eggs outback. Friday will be the day the eggs are at the same stage in the incubation process. The abandoned eggs have been cold for nearing 2 weeks. Can i foster the abandoned 4 eggs into the active TRES nest with 6 eggs to see if they are viable and hatch? I also have an almost complete EABL nest. Could i place 2 abandonded eggs in the active TRES nest and 2 abandoned eggs in the active EABL nest when the time is right? i need opinions by Friday please. If i do foster them, i am going to make a mark on them with a marker to be able to tell them apart. Should i remove the nest after fostering the eggs to let the male start over and maybe try and attract another mate? any help and advice is greatly appreciated. this list is wonderful

thanks

Tyler in West Central OH

From: Keith & Sandy Kridler [mailto:txbluebirder"at"sbcglobal.net]
Sent: Saturday, May 28, 2005 7:19 AM
Subject: RE:HELP! Question with fostering abandoned TRES eggs

Keith Kridler Mt. Pleasant, Texas
After a week of being incubated the blood vessels and nerves and tissue were rapidly forming in the eggs. When the temperatures dropped below about 80*F this process almost stopped. After three or four days without the eggs being rotated or turned by the female or kept warm the forming process converting the egg yolk and white into tissue stopped and the embryo's will have died.

Anytime you try to foster eggs from one nest into another you have a greater chance of losing both nests of eggs since the timing of incubation and hatching has to be precisely timed to prevent competition between these young birds. What different species feed their young also is important.

It is actually illegal to move these native bird eggs to another native bird nest. (I know the folks at Cornell wanted me to remind the list:-)) KK

From: RMoore1718"at"aol.com [mailto:RMoore1718"at"aol.com]
Sent: Thursday, June 02, 2005 4:21 PM
Subject: WHAT IS NORMAL?

I HAVE A QUESTION: FOR THE PAST SEVERAL YEARS I HAVE HAD A BLUEBIRD BUILD A NEST IN MY BACK YARD. THIS YEAR THEY BUILD A NEST, HOWEVER, I HAVE NOT SEEN THEM SINCE, DOES ANYONE HAVE AN SGGESTIONS AS TO WHY THEY WOULD ABANDON THE NEST.? IS IT NORMAL FOR BIRDS TO ABANDON THEIR NEST?. THANKS BOB.

GAMBRILLS MD.

This is my dilemma. I had a pair of bluebirds that chose to nest about 100 yards from me. But they came to the feeders and took the bluebird banquet back to feed their babies and then brought their fledglings to the feeder. They showed interest in my nest box, but then appeared to fly back to where the nested the first time. In the mean time, I had a second pair show up to the feeders to take the bluebird banquet to their babies. I'm sure the female is the offspring of the first pair who had been with them all winter. They seemed to time it right to where neither pair showed up to the feeders at the same time. Then this pair started bringing their fledglings to the feeder. Well the female from the second pair really took interest in the nest box. But the first pair returned to the feeders and found the second pair in the territory and they began to fight. It seemed like the first pair ran off the other pair and their 2 fledglings. The female from the first pair began building a nest in my nest box. She only built a partial nest and has not been back since. Will bluebirds build a partial nest to make another pair think that the nest box is occupied while they really have a nest somewhere else?????

Tina Wertz
Woodstock, Ga.

Tina,

I'm not sure about anything when it comes to bird behavior, but I believe the pair in my yard have done the same thing. This year the swallows arrived just after the first chicks fledged, and were interested in the two empty nestboxes. The bluebird pair started guarding "their" territory, and chasing the swallows. They then built a partial nest in one box and a complete nest in the othere, where they now have five eggs. I've left the partial nest, since the swallows are already nesting elsewhere. You never know what these birds will do!

Barbara in Cloverdale, CA

Hi, Tina.

What you described is normal during the nesting season. The Patuxent Wildlife Research Center site at http://www.pwrc.usgs.gov/ is down today, one of my resources for factual info on things like the area dominated by species...
but, if memory serves, a Bluebird pair will try to dominate an area of 3 - 5 acres, occasionally much more. That's why a spacing of 100 yards or more between nestboxes is recommended. In my experience, that the area dominated shrinks when they're busy feeding nestlings.

BUT that applies to open areas. In many cases, Bluebird pairs will nest much closer if there is a barrier between the nestboxes. I occasionally get 3 pair to nest on my property, just under 5 acres. One pair nests near the grape arbor at the back of the house, dominating the farm field beside the house. Another will choose a box down by the stream and dominate much of my open area with the Purple Martin houses and garden.
If I'm lucky (rarely), a third pair may nest in a box near the road, separated from the other pairs by our house, the barn and the trees and bushes around the house/barn and dominate the pasture across the road.

Who knows what a pair of Bluebirds will like?
You might try moving a box or reorienting the direction of the entrance. Birds sometimes pick a box that violates all the rules. I had a pair of Tree Swallows that insisted on occupying a nestbox trap attached to the barn. I got so tired of taking the male TRES out of the trap that I removed the metal trap door and left them to nest there (unsuccessfully, by the way).

Take care,

R J 'Tree' Greenwood
Catlett VA

How long has it been? It's not unusual to see a gap between the completion of the nest and the egg laying process, so maybe they haven't really abandoned. Also, the less "committed" the birds are to the nest, the less likely you are to see them around. We had one pair that we really never saw until they had eggs, and then they were there every day! It was quite amazing the disparity.

Kathy Haines
Central Ohio

Hello everyone.

A few weeks ago this newbie inquired about the four lonely eggs and the weird TX weather, not sure if mama had abandoned the nest or been chased off. I've tried the blade of grass in the opening trick, but the wind has been blowing it out. I've not seen mama or daddy bluebird from this nest and the eggs should have hatched today but they are still just sitting there, alone. Someone gave me the advice to give it two extra weeks, but I'm afraid that the little eggs are now nothing more than a sad, but beautiful little decoration inside my house. Do I give up on them? (It breaks my heart to think so.)

Also, another question...the first pair (that made this deserted nest and fledged 4 earlier) know that we feed meal worms. Would they try to come back for worms even if there is another pair now in the yard or is that part of the territory thing? Are Bluebirds territorial in Winter too?

Kat

As a fellow Texan, I know what you mean by weird Texas weather! It does sound as if your eggs are abandoned. I would remove them, and the nest as well, perhaps saving it as an emergency nest replacement. "My" bluebirds like a clean nestbox to start with.

If another pair has taken over your yard, they will probably protect the mealworm feeder also. That's one of the reasons I don't feed mealworms.
Even in winter you feed only a few bluebirds, probably a family group, at least around here. Mine stay all winter and seem to watch over their nestboxes. With all the insects here, I want my bluebirds to eat what nature provides!

Kate Arnold
Paris, TX, 100 mi NE of Dallas

From: Autumn L. Kruer [mailto:autumnk"at"iglou.com]
Sent: Tuesday, June 14, 2005 1:49 PM
Subject: Daddy bluebird is BACK!

Big sigh of relief. Y’all don’t laugh at me, but it made me cry when I just spotted him at the nest box. I have no iota where he was, but he’s back now. Watching that female bluebird call and call for him in her feeble little song was breaking my heart. I hope she scolded him well!

Autumn

From: Lana Hunt [mailto:lanahunt"at"kcp.uky.edu]
Sent: Wednesday, June 15, 2005 12:45 PM
Subject: Re: Daddy bluebird is BACK!

Autumn
Autumn, I wouldn't dare laugh at you. I think it's very human to worry about small creatures, your crying is testimony that you are a very caring person. I'm happy for you and Mrs. Blue that he's back! Lana

Hi, Kat.

Nesting BB are very territorial and will try to drive away any other BBs that venture into their chosen territory. Average circumference of a BB's territory is about 300' during the mating and nesting phases. In my experience, the size of the territory that a pair defends shrinks as activity switches from nest building to brooding to feeding nestlings. I guess they're too busy finding food for babies to worry about other BBs at the edges of their territory.

So the pair nesting in your yard is likely to try to drive away any and all intruding BBS of the same sex (I've seen reports of polygamous male BBs but I've never personally seen that).
BBs that I personally watched usually act as a pair in driving out intruders but the male is alway more aggressive against intruding males and the female against other females.

> Are Bluebirds territorial in Winter too?

Definitely NOT! They're pretty sociable even though you'll see some squabbles. It'll be up to banders or ornithologists with permits to determine if the flocks of BBs we sometimes see are family groups of related birds or if they really do flock outside the nesting season. When the weather is bitterly cold, a dozen BBs may huddle together in a cavity for warmth.

Bluebirds, at least my Eastern variety, are only territorial from spring until after fledglings are on their own. Then they appear to be quite sociable but possibly only in flocks of biologically related birds. Anyone know of studies on whether it's only related birds in groups? I don't but would love to know for sure.

Take care,

R J 'Tree' Greenwood
Catlett VA

Ok, the parents of the lone egg never did return after the other three eggs were systematically removed by something, (found out we don't have House Wrens here) but...there is better news. Thrilled to report that we have new tenants! We literally had just taken that really old nest with the 4 old eggs out of a house only about an hour before they showed up. I'm not totally positive, but I believe this is actually the first pair that fledged four earlier this year from our yard. It was really cute. They wanted to look at both available units. Daddy chose the more eastern house, but Mama, being a true blue female, couldn't make up her mind ( that was too easy) and she went for the more western house. (These are actually bluebird houses and not decorative.) Both are identical houses so not sure what the deal is. We discovered later that they put a deposit down on the easter house as grass was found inside, but then returned to put a deposit down on the western house as well. They seem to be at odds over which unit they will take. Once they make up their mind, we will install the cable antenna (sparrow spooker). They seem like such a nice couple. LOL! We have been watching them for the past 3-4 days and three of the previous babies are with them, periodically. Here's the odd part. We have watched them start nests in BOTH boxes. The boxes are on the same fence and only about 15 feet apart. Why would they build in both houses? And what's up with the little ones being there too? (Not that we mind at all...they are funny to watch.) And they actually are drinking from the bird bath. : ) First time all year. Life is good again. (Yes, I'm easily entertained, so what!) Kat Frisco, TX

From: Susan Lodewick [mailto:slodewick61"at"comcast.net]
Sent: Monday, July 18, 2005 4:57 PM
Subject: Abandoned nest

I am new to this forum and to bluebirds! This summer I have bluebirds nesting in my Gilbertson box and feeding at the meal worm feeder. Earlier they nested elsewhere but came to the feeder to eat. The problem...they seem to have abandoned their nest with four beautiful eggs. I haven't seen them and the meal worms are not being consumed. What could have caused this? Perhaps I can correct the problem for the future. Thank you in advance.
Susan Lodewick from Ipswich, MA

From: Jean Carter Wilson [mailto:peanut123"at"comcast.net]
Sent: Monday, July 18, 2005 5:23 PM
Subject: Re: Abandoned nest

Um, do you have snakes or raccoons around? That may be your problem...

Also, how long has it been?

Hi, Susan,

It's probably too early to worry. I checked your weather up there in Ipswich, MA. Upper 80's for temps and 80+ % humidity. If your nestbox is in the sun, momma BB can spend lots of time out foraging for meals from natural sources. She may prefer natural foods to your mealworms right now.
The eggs will continue to incubate from the sun's warmth and the high temp's without momma BB constantly brooding.

It is possible that a predator got your pair but it's just as likely that your BB parents are just doing what's natural for them at this time of year. Continue to monitor your nestbox and you'll likely see your bluebirds very early and very late in the day. Mom will brood her eggs through the cool hours of the night but may take off again once the sun is well up.

Unless the eggs have been there for several weeks, I recommend leaving them. See what happens. I'm hoping you'll get a pleasant surprise when they hatch and you're monitoring nestlings.

Only if you can identify a problem. Sometimes a nest is abandoned for no reason that humans can discern. An abandoned nest isn't always because of something we did or didn't do.

Take care and hoping for the best,

R J 'Tree' Greenwood
Catlett VT

Tree,

I think you have it spot on. I have a third nesting with the temps in the mid to upper 80s with humidity every day. In the last 10 days, of nest checking, I've caught the female on the nest once, and even then she was setting off to the side, not on the eggs. And, mealworm consumption has dropped way off, likely due to the reduced need to maintain body temperature in the warm air and no gapers to feed--yet.

Jean, the easiest telltale for nest activity is egg position. Look at the eggs in the nest and memorize a couple key egg positions or alignments. If that hasn't changed within a day or two, then you may have a parent problem. Currently, I go for days without seeing the parents of this nearby nest, yet when I check the nest in the morning, the eggs are always rearranged...a sure tell.

Chuck

I have a question for all of you experienced bluebirders -- Toward the end of the season as I was checking all the boxes on our trails, I seemed to find a disproportionate amount of seemingly new nests, ready for eggs, which were just abandoned. I can't tell you how many out of our 279 boxes, but there were way more than we have had in the last several years. Could some kind of predator bird have discovered that there were easy meals to be had if they just hung around those boxes?
We had 5 gallon buckets on almost all the boxes, to protect against snakes and coons but nothing to protect against any flying predators.
Any ideas?

Jeanette, I've had this happen also. It was on the third cycle. They built a complete perfect nest in one that was paired and then decided to move to the other nestbox ten feet away and slapped a nest together. I am wondering if the Chickadee that nested there on the second cycle may have harassed them.

We have a member that took his grandchildren out during the Christmas Holidays to show them the nestbox and explain to them what monitoring means and he found a complete nest with five eggs that had been made and laid after he cleaned it out the last of August. He really did have a "show and tell" presentation!!!

Evelyn Cooper
Delhi, LA

I think sometimes the day length "tricks" birds into exhibiting spring-like behavior in the fall. They abandon the nests once they "come to their senses" so to speak. Some have also suggested that young birds are "practicing" their nest-building skills, although their hormones are not ready for a true nesting cycle.

Some birds may try late nesting in earnest, as Evelyn mentioned, but the eggs may be infertile, due to the lack of hormones in the male at this time of year.

At any rate I believe the nests are abandoned in favor of more seasonal behavior, with winter coming on.

Kate Arnold
Paris, Texas

I think Kate is right. Bluebirds are often fooled by the weather, and start just one more optimistic nesting late in the Summer or in early Fall if the weather remains summery longer than usual. Then when reality finally sets in, and the weather turns cool or cold, they abandon the nesting and start shifting into their Autumn mode, sometimes with a completed nest, sometimes even with a few eggs.
Here where we are, in SW NH, they give up all serious thoughts of nesting when the supply of live insects begins to run out.They can eke out a living on seeds and berries, but they can't feed a nestful of chicks with them.

Bruce Burdett, SW NH

I have a question for all of you experienced bluebirders -- Toward the end of the season as I was checking all the boxes on our trails, I seemed to find a disproportionate amount of seemingly new nests, ready for eggs, which were just abandoned. I can't tell you how many out of our 279 boxes, but there were way more than we have had in the last several years. Could some kind of predator bird have discovered that there were easy meals to be had if they just hung around those boxes?
We had 5 gallon buckets on almost all the boxes, to protect against snakes and coons but nothing to protect against any flying predators.
Any ideas?

Jeanette, how deep are your boxes (bottom of hole to floor)?
Avian predators (hawks, jays, crows) on my trail were a problem until the hole-to-floor drop was increased to 8.5 inches. Typical hole-to-floor depths are only 6.5 inches (NABS standards). The extra 2 inches is critical on my trail.

Linda Violett
Yorba Linda, CA

Jeanette, I've had this happen also. It was on the third cycle. They built a complete perfect nest in one that was paired and then decided to move to the other nestbox ten feet away and slapped a nest together. I am wondering if the Chickadee that nested there on the second cycle may have harassed them.

We have a member that took his grandchildren out during the Christmas Holidays to show them the nestbox and explain to them what monitoring means and he found a complete nest with five eggs that had been made and laid after he cleaned it out the last of August. He really did have a "show and tell" presentation!!!

Evelyn Cooper
Delhi, LA

When responding to Jeanette Stramm's call for help, it is important to note that she is an experienced monitor (several years) and is referencing a large trail (279 boxes). When she says she is experiencing a large number of unfinished/abandoned nests during the latter portion of the nesting
season, it is an unusual situation for her. Some empty/abandoned nests
might be due to a late attempt in the season as others have mentioned, but since this is unusual for her, it might be something else. She (logically) looks to other possible causes, such as avian predation.

Evelyn's response centers around lowering a new nest which has been built on
top of an old nest. But monitors who check their boxes on a weekly basis
and promptly remove old nests will not have new (high) nests built over old nests. I doubt this is Jeanette Stramm's problem.

In regards to Gary's tip (via Evelyn):
"He said after the female
> lays the egg, to always take a little of the bottom of the nest out to
lower
> it to protect it. In any of your boxes that have the standard hole to
floor
> measurements, that would be a good idea."

While Gary's tip is to wait until the first egg is laid and lower the nest, my tip is to build deeper boxes so you don't have to remove any nesting material . . . regardless of when the first egg is laid.

Standard NABS boxes with 6.5" hole-to-floor depths are EASILY raided by avian predators on my trail (hawks, crows, jays, starlings). Boxes with 8.5" hole-to-floor depths solved avian predation and may provide Jeanette with a solution *if* her problem turns out to be caused by avian predation.

But monitors are hesitant to build deeper boxes because otherwise reliable monitors advise against building deeper boxes. Gary Springer (in past discussions on deep boxes) has stated "Regarding deeper nest boxes and the distance from the nest box hole down to the bottom of the nestcup upon which the eggs and chicks rest, my experience apparently mirrors Ann Wick's. On my trails, more than 50 percent of the time the Eastern Bluebird builds the nest high enough so she can look out the hole while sitting on the nest. "

Here is a sampling of photos from my trail showing normal nest construction in deep boxes. http://home.earthlink.net/~lviolett/claimstraws.html These photos were taken and uploaded as the season progressed. Gary Springer and Ann Wick have yet to provide a similar progression series showing their birds building nests up to the hole of 8.5" hole-to-floor boxes.

In the meantime, monitors who are experiencing an unusual amount of mysteriously empty/abandoned nests should consider building deeper boxes.

Linda Violett
Yorba Linda, Calif.

Hi Linda, Evelyn and All,

Although I don't have a large trail, I've been monitoring for a several years, and I find unfinished nests at the end of the season nearly every year -- some complete with eggs, some empty. I've never had EABLs fledge after the first week of August. (Doesn't mean it won't happen, but it hasn't yet.)

Occasionally, I find nests built over new nests with eggs. Sometimes before I have time to remove an old nest, a new nest is started on top of the old one. I monitor my golf course trail weekly, nest boxes in my yard more often.

I've also had a few birds continue building until their nests reaches the entrance hole, and I'm convinced they would build nests a foot high to reach the entrance. Maybe they like to look out, or maybe they don't know when to stop building!

Also, most of my abandoned nests coincide with house wren nesting activity which usually begins after my first EABL nestlings fledge.

MJ

Mary Jane Shearer; Tucker, GA (N/E Atlanta)

OK, Evelyn. Sorry I missed that. Lowering the nest would be a simpler (and more economical) solution than replacing shallow nest boxes with the deeper style boxes.

MJ

Mary Jane Shearer; Tucker, GA

Hi Jeanette,

If it's a flying predator, it didn't take the bird out of the nestbox. When i catch the adult in the box (which doesn't happen often with bluebirds), it holds onto the nest with its feet as i'm pulling it out to band it. I often have to smooth the nest back into shape.

It could be that your weather was just very confusing to the birds & they thought they had a good chance to lay another clutch but then decided against it. Here in southern Michigan, it was very dry the end of the summer, which definitely affected the numbers of bugs.
Was your weather very different from previous years?

Those are my thoughts. Wish we could just ask the birds so we wouldn't have to guess.

yours, Torrey

Torrey Moss
Kalamazoo Nature Center
Kalamazoo, MI

Hi Evelyn,

I’ve emailed you in the past with concerns around my bluebird box. This year I have two new parents and she laid 5 eggs. I saw her on the nest Sunday, but haven’t seen either of them since. I checked the nest Monday evening and grass from the nest has been placed over the eggs. Do you think anything happened to the parents maybe? What should I expect or do?

Thanks for your help,

Aileen

Yes, something has run the bluebirds off. It might be a Carolina Chickadee trying to take the nest from them. I don't know if you've seen one around or not. If it was a House Sparrow, usually they throw the eggs out. If you think you have a Carolina Chickadee, you could put up another box about 10 feet away and maybe whatever is bothering your Bluebirds will take that box. The best thing to do is try to keep a close eye and see what is going to the box.

This would be a good thing for others to see and maybe they have some suggestions. Let me know if I can forward it to them.

Evelyn

I recieved this from a last years "newbie" at bluebirding and wondered if any of you had any other suggestions. One person said to me it could be a bluebird pair trying to take over the nest. If so, if she has the room, she needs to place another box the right distance for another bluebird pair.

Evelyn

From: David Gwin [mailto:David.Gwin"at"cityofcarrollton.com]
Sent: Friday, March 10, 2006 10:56 AM
Subject: RE: Bluebird Eggs

Evelyn:

I would bet money that she has two pair competing for the same box. She needs to add another box at the approapriate distance.

In fact, if competion is as tight as it appears, she may want to add two new boxes.

Enjoy,
David

Hi...1 of my EABL nests has 3 cold eggs there for about 8 or 9 days & I'm wondering if the nest has been abandomed or if the female perhaps has been killed? Actually a week before last Tues., the 4th egg was laid. Then after about 4 or 5 days when I checked the nest, I saw 1 egg with a hole in it. So I removed that egg, leaving 3 (cold) eggs there that looked ok. I've seen the male or a male hanging around occasionally, but no female. It's too early for the House Wrens to be here (to do their damage). I've seen Chickadees sometimes checking out the box. I'm wondering if the Chickadee punched the hole in that 1 egg?
Another question.. can I assume that the 3 eggs have been abandomed. I noticed that in my neighborhood area, the EABL have started their nesting earlier(about a week) than in previous years, probably because of nice weather. I may wait a few more days before removing the 3 cold eggs & save them for other nests..maybe put 1 egg in each of other 3 boxes at the start of egg laying. If I decide to do that, how long will these 3 eggs be viable? Thanks for any good reliable info..... Horace in Durham, N. C

You might wait a little longer to see if the eggs are truly abandoned, but if you decide they are, I wouldn't bother saving the eggs to place in other nests. You could spread germs that way, and you really don't know what stage these eggs are at. It's one thing to foster nestlings, but eggs are a different story in my opinion. It would be different if we were dealing with an endangered species, but bluebirds are plentiful in many areas. As they age, the eggs will dry out inside, and the shells become more brittle, meaning the old egg could break. This can make a mess, could draw predators, and has even been known to "glue" a nestling down.

Kate Arnold
Paris, Texas

From: Carol McDermott [mailto:mcdermott.c"at"comcast.net]
Sent: Monday, April 03, 2006 11:01 AM
Subject: Seeking advice on abandoned EBB nests with eggs

My question is if freezing temps will cause eastern bluebirds to abandon their eggs and start new nests? I live in Atlanta, Georgia and I had two different nestings with 4 eggs each on approximately March 26 and 27. On March 27 and 28, after very warm weather, our temps hit 32 degrees as a low for 2 days in a row. As of today, March 2nd both nest appear to be abandoned and we believe the very same pairs have built new nest in near by boxes (no eggs yet). Due to being so territorial we do not think these are new pairs building nest for the first time but our same original two pairs. If not the weather does anyone have any other thoughts or experiences with abandoned eggs?
Carol
Atlanta, Georgia

Hi Carol,

Given what you've told us, it certainly does sound like the birds abandoned their nests due to bad weather. Eggs are pretty tough before incubation begins & can handle some chilling after the embryos start developing, but prolonged cold will destroy them. The adults can sense this (i'd really like to know how) & will try again.

Bad weather can be a one-two punch: The adults have to search longer & harder for food, & the eggs (or young nestlings) chill faster.

Keep an eye on those 2 nests -- I've had some eggs that always feel cold to my fingers but hatch on time anyways. You can put a piece of grass across the entrance hole to check if birds are going in the box, like in an old-time mystery movie. I normally give my potentially abandoned eggs a week before i take them out, but i only monitor once a week. Definitely remove them if a new nest is being built over them.

There's still plenty of time left in the season, & hopefully the weather will be more cooperative.

Torrey Wenger
Kalamazoo Nature Center
Kalamazoo, MI

You already got some good answers to this question BUT temperature data loggers and other data will show that eggs can survive sub freezing temperatures and remain viable.

Freezing temperatures can remove the high protein diet of live insects in the area. Birds might realize that there would not be enough food for their young if they hatched out shortly after a hard freeze. As others have mentioned it might be simply that they need to be away from the nest too much just to feed themselves.

Cornell is working on tracking egg temperatures with temperature data loggers. Back in March of 2004 they had data that showed a female bluebird leaving the nest and her eggs were 94*F and in 10 minutes they had dropped to 48*F. It took the female 22 minutes to heat these eggs back up to 94*F.

Now IF these eggs had been almost frozen would the female bluebird have been able to even warm ALL of them up to the correct temperature. Would this take too long and lead to a higher percentage of birth defects? Can a BIRD actually know this?

From Cornell's sheet on this subject: Embryonic development is suspended below 26*C (78*F). Between 26*C and around 36*C,(97*F) development is slow but not impaired, yet prolonged exposure can cause developmental abnormalities. The most rapid embryonic development occurs between 36*C and around 40.5*C (105*F) . Embryos usually die if temperatures exceed 40.5*C.

In another study with House Wrens, heating their eggs or young birds to a core temperature of 107*F killed all of them in a matter of hours. KK

Hello... when I wrote last week of the 3 cold apparently abandoned EABL eggs & that I may try to save them, several people wrote me to let them know what's happening. So here's what I plan to do. It's been 16 days since the 4th egg was laid.
If you remember, I said there were originally 4 eggs laid back in mid March, & a few days after that, I removed 1 egg that had a hole punched in it. So there remained 3 eggs, not being incubated for about 10 days. (I suspected something scared off the
female.) Then I removed those 3 eggs & stored them in a cool dry place. Meanwhile, a female ( I believe was the female that abandoned her eggs in the 1st place) has laid an egg yesterday in the nest. If she lays 3 or 4 eggs total, I'm going to sneak 1 or 2 of the other eggs (which I'll
mark)
in there to try to get them hatched. The chances are they're not going to hatch, but then maybe there's a small chance 1 might....but it'll be interesting to see if any hatch. I've got another box down the street which today has the 3rd egg laid today. I'll do the same thing there, also.... Horace in Durham, N. C.

Hi...Just to bring you up to date on what I did with the 3 abandoned EABL eggs. Yesterday, I put
1 of them in a box of 5 eggs which she started incubating yesterday. Today, I put the remaining
2 eggs in another box of 4 eggs which she started incubation today. So both boxes each have a total of 6 eggs. The 3 eggs are marked. I did observe both boxes for awhile to see that both females are incubating. So that's ok. So the interesting question now is whether any of the 3 eggs will hatch. The 3 eggs have been in a cool dry place for about a couple of weeks or so. I have a question for anyone who has some knowledge or experience with the following. 1st of all the average no. of eggs laid in my area for the 1st cycle is 4 or 5...sometimes 6 occasionally but not often. I heard of maybe 6 or 7 or more further south or west. Many times when I have a batch of say 5 or 6, 1 turns out to be infertile.
Almost always when I see 4 eggs, all 4 are good.
My question is: has anyone ever had a batch of more than 6 or 7 or 8, e.t.c.? And how many of those did hatch and how many of the nestlings did fledge ok? Thanks.... Horace in Durham, NC

From: Amy Louise Marr [mailto:MARR_AMY_LOUISE"at"Lilly.com]
Sent: Tuesday, April 11, 2006 7:11 AM
Subject: Re: The 3 abandoned eggs & what I'm doing...

Hi
I have worked with chickens and chicken eggs, and wanted to comment on the egg storage and attempted fostering of the abandoned eggs. Broiler eggs are routinely stored for short durations prior to setting. However, extended periods of storage will result in dramatic decreases in % hatch.
Here is an excerpt from a U of Florida cooperative extension paper. Consider that these eggs were stored under ideal controlled temp and humidity conditions.

If your eggs have been stored several weeks, unfortunately I don't think they're going to hatch.

I would suggest removing the fostered eggs from the new nests. This will reduce the chance of having one of them exploding ( it does happen!) and spreading bacteria. Overall, removing the old eggs will give the fresh eggs a better chance....

Management of Hatching Eggs and Broiler Performance
G. D. Butcher, DVM, Ph.D., Amir H. Nilipour, Ph.D.

University of Florida Extension

Duration of storage of hatching eggs can have a dramatic impact on percent hatchability. The results of two large studies, conducted by the authors, demonstrated that fertile eggs held under recommended conditions of temperature and humidity completely failed to hatch when held in storage for more than 25 days. Even after 7 days storage, a significant reduction in hatchability was noted (Table 1). To achieve maximum percent hatch, the authors recommend to store eggs not more than 3 days in the egg room and maintain the egg holding room at a temperature of 65°F and relative humidity (RH%) of approximately 78%. These temperatures and RH% settings need to be adjusted when egg storage periods are prolonged in an effort to conserve the internal integrity of the eggs. As a rule of thumb, as the egg storage time increases, storage room temperature should be decreased and the relative humidity increased to prevent dehydration.

Table 1. The effect of egg storage on % of hatchability.
Days of storage Trial 1 Trial 2
3                            87       90
8                            70       76
12                          60       50
16                          26       17
20                          17       13
23                            7         3
26-35                       0         0

Amy Marr

Greenfield, IN 46140

Keith Kridler Mt. Pleasant, Texas
I have had 7 baby Eastern Bluebirds in a couple of nestboxes over the years.
One was in a 4" PVC nestbox and they were stacked up on top of each other before they fledged. I have 7 bluebird eggs in a box near down town Mt.
Pleasant now.

More eggs from larger clutches will hatch during cool to cold springs when compared to larger clutches in the heat of summer as any temperatures over about 75*F will start the formation of blood vessels and nerve growth.

Low humidity during incubation or even low humidity before the eggs are incubated will allow the eggs to lose moisture. Somewhere I have a chart that shows how much weight % wise an egg should lose in order to hatch correctly. If the egg does not lose enough moisture the baby birds will be too high in moisture content and suffer birth defects. If they lose too much water weight wise before hatching they will be too dry and stick in the shells or have other problems.

Over the years we normally fledged on average 4.5 baby birds from the first nesting attempts. Second nesting we usually fledged 3.5 baby birds from each nest. Third and fourth nesting attempts in the heat of summer were down to an average of 2.5 baby birds fledged per attempt.

Part of this is due to smaller clutches laid on average later in the summer, part is due to fewer eggs that hatched and part is due to higher mortality due to predators and higher heat later in the summer. It is pretty common in late July and August for bluebirds to lay eggs and then never seem to incubate them.

Bluebirds in Texas will start laying eggs the end of January and it is pretty common to have baby birds in nestboxes still in early September.
During this time frame I have seen more than 100 days reach or exceed 100*F and still fledge a lot of bluebirds.

The BTO website on House Sparrows in the UK showed the average clutch size is 4.1 eggs per attempt on average. They raised almost $190,000 for research for their sparrows and had more than 16,000 backyard researchers that submitted more than 11,000 sets of backyard nestbox data (they call them
gardens) on the House Sparrows. They show that carefully monitored boxes fledge more young but they are losing even more % wise House Sparrows after nesting season before they get old enough to breed. The dropping population of House Sparrows in the UK is probably due to the fact that there is just so much habitat that is ideal.

Same goes for bluebirds in the USA in certain areas. No matter how many baby bluebirds you have fledge there HAS to be somewhere for them to forage safely during the winter and in the following spring there HAS to be somewhere for them to nest and forage for food for their young. KK

Yes, I've had 7 eggs hatch and all 7 chicks fledge, but never in a boxes
with small floor sizes.
If you go to the "floor size" web page and scroll down a bit, you will see a
5x6 floor that contained 7 chicks (they all fledged).
http://home.earthlink.net/~lviolett/floorsize.html

Linda Violett
Yorba Linda, Calif.

From: Evelyn Cooper [mailto:emcooper"at"bayou.com]
Sent: Tuesday, April 11, 2006 2:30 PM
Subject: Re: The 3 abandoned eggs & what I'm doing...

Horace, two years ago, I had six fledge from a 4 x 4 floor. It was on the first cycle and remember, these little birds are used to snuggling and even sitting on top of each other. It being the first cycle and having some cool to warm weather, I think they will be fine.

Evelyn, Dehli LA

Hi...A couple people advised me to take the eggs out. A couple people said leave them in. They said it'll be ok. Since I do monitor my boxes often for trouble, I've decided to leave the eggs in, to learn if the eggs were or were not viable.
If it were a 2nd cycle, I wouldn't have done it.
Today, she laid her 5th egg in 1 of them making the total = 7 eggs in that box. Her 5 + 2 extra = 7. So 1 box has 6 eggs & the other has 7....Horace in NC.

From: Fultons [mailto:thefultons"at"everestkc.net]
Sent: Monday, April 24, 2006 4:31 PM
Subject: abandoned nest, possibly?

Bluebird Listers...

I checked nest box over Easter weekend and had 5 eggs. I have not noticed much activity around the nest box lately. No male sitting on top of the box and hanging out close by in trees/fence. Temps have been fairly warm during the day but dropping into 50's over night. Today only in the mid 60's and tomorrow only low 50's!!! Just went out this afternoon and two eggs are on the ground. Both had a hole in them and one still had the stuff inside but the other did not. Checked the other three eggs in the box and all of them have not been disturbed or destroyed. Not sure if I should leave the three alone and watch and see if parents return or if I should remove eggs and nest and see if they start over. All the while I was out there messing inside the box, not a parent to be seen to scold me for being so close. I did see a pair at my bird bath yesterday (Sunday). Have been putting out mealworms too and they are not disappearing at all!!

Any thoughts?

Thanks,
Cristy Fulton
Lenexa, KS

From: lviolett [mailto:lviolett"at"earthlink.net]
Sent: Monday, April 24, 2006 11:46 PM
Subject: Re: abandoned nest, possibly?

Leave the eggs in the box alone.
There is no advantage to removing the eggs if they have been abandoned.
If the eggs have not been abandoned, there certainly is a disadvantage if you remove them.

Sounds like you had a House Wren destroy part of the clutch. This has happened on my trail where a couple of eggs were destroyed by wrens and the Bluebird parents became more vigilant and fledged the remainder.

Don't second guess what is happening, wait and watch. If a new nest starts to be built over the old eggs, remove the old eggs.

Linda Violett
Yorba Linda, Calif.

From: Fultons [mailto:thefultons"at"everestkc.net]
Sent: Tuesday, April 25, 2006 7:54 AM
Subject: UPDATE to "abandoned nest, possiblty?"

Thank you to those who have responded to my previous email. Now for a new development...

I put a piece of grass in the hole of the nest box last night about 7:30...this a.m. that grass is still there. So that means that the mother never went into the box last night to sit on the nest! Temps were in the low 50's over night! Would it be safe to assume that those eggs are not viable since they have obviously NOT been incubated overnight? I have a neighbor that says she has two pairs in her yard. One is building in her "normal" nest box...one is trying to build in an "ornamental" type nestbox on her deck. Maybe one of them could be the pair that was initially in my nest box. Just wondering if I should clean the eggs/nest since she obviously was not in there last night or if I should continue to leave it along.

Thanks again for your suggestions.

Cristy
Lenexa, KS

From: denisefarmer"at"comcast.net [mailto:denisefarmer"at"comcast.net]
Sent: Tuesday, May 02, 2006 8:58 PM
Subject: Sad Day for my TreSw , BB Egg?

Hi All,

Recall last week I said I found a Tree Swallow laying in the bottom of a box. It went flying off and sadly today, that same box had a dead tree swallow in it. I cannot be sure if the same one or not but I am assuming it is. Sadly the nest box plans I was given did not talk about having a "ladder" for the TreSw to help use as an exit. I took a nail today and gouged ladders as best I could today and I am taking my speed saw Thursday to put in true ladders like I saw on a TreSw nest box from the Sialis website. I am crushed and feel terrible

Today when I arrived at the nest boxes the Momma BB was NOT on her nest and she has four eggs in this nest. She was on the nest last week. Do you think she deserted the nest? There are no HOWR or HOSP in this area that I have ever seen. There are lots of TreSw but other then that I have not seen any other cavity nesting bird on this trail. Does the mother leave the eggs during the day during incubation? I hope the eggs will be ok.

I had two other boxes with claim straws and one empty box (well it had two spiders which I killed)

Denise (very sad and upset about the TreSw and my ignorance that killed one)
Parkville MD

Denise --

It's not uncommon for the female to leave the eggs during the day, especially if it's a moderately warm to hot one. Cornell's TBN site has some studies about incubation related to temperature of the nest, and from those you can see that the female wasn't on the eggs all the time. In recent weeks I've checked nests where the female was present and others where she wasn't. If she's there, close the box, back away (preferably behind it) a short distance, continue talking so she knows you're still there and wait a minute or two. Sometimes she'll leave the box, sometimes she'll stay -- many times for me, she leave the box. Do a quick check, then let her be. She'll come back shortly. And the eggs will be fine. If she doesn't leave, then just come back later or wait until the next day. Good luck --J

Jimmy Dodson
Asst Forest Manager -- NCSU Dept of Forestry & Environmental Resources
Campus: 3024B Biltmore Hall, Raleigh, NC

From: Bet Zimmerman [mailto:ezdz"at"charter.net]
Sent: Monday, May 08, 2006 1:32 PM
Subject: RE: abandoned nest, possibly?

Doesn’t removing the old eggs (IF TRULY abandoned or CERTAINLY infertile) encourage a new clutch?

Bet from CT

Bet and All,

Is there any real evidence, or actual proof, that removing old eggs encourages or stimulates a new clutch? I have read that over and over on Bluebird-L and that is not what I have seen on my trail. What I *have* seen is sometimes a rare clutch is abandoned/infertile or not incubated for some reason. When this occurs, the box is not avoided or left inactive for any period of time. The eggs are either removed or new nest material is built over the old eggs. Sometimes the transition is so quick that I don't even discover old buried eggs until after the fledged nest is removed.

From my experience, old eggs do not in any way deter new activity but removing eggs (assumed to be old, but really a new clutch) could certainly cause problems. Let's say a monitor were to see warm eggs in a nest one week and warm eggs again the following week. Then the eggs were buried or removed by nesting birds (same pair or competing pair) and a new clutch quickly laid. Later, the monitor revisits the nest and sees (new) cold eggs but assumes the eggs are old and abandoned and tosses out the "old" cold eggs.

Backyard Bluebirds have the advantage of watching eggs on a daily basis but still, the question is whether removing old eggs actually stimulates or encourages a new nest attempt.

Bet is doing a good job in weeding out myths . . . the notion that removing "old" eggs to encourage new nest attempts may be one of those myths.

Linda Violett
Yorba Linda, Calif.

Telling whether eggs are abandoned is a matter of time. I make that assumption after there has been no activity for several weeks, then I remove the eggs. Every time I have done so, I have opened the eggs and found them to be defective in some way—dried out, infertile, or in one case “cooked” by the hot sun in a box with extremely thin roof and walls in full sun in 100+ weather (nestbox removed and replaced with better nestbox in afternoon shade).

I don’t leave the old eggs in the nest—first of all I get faster nesting if I give the birds a cleaned-out box, and secondly, I don’t want the eggs to perhaps explode in the heat or break and cause problems.

Kate Arnold
Paris, Texas

Hi Bet and group,

I'm not sure how one would tell if Bluebird eggs are "truly abandoned or certainly infertile". Is anyone else here? With larger waterfowl or chicken eggs you can "candle" them by placing the egg on a toilet paper roll and shining a flashlight through the opposite end of the roll in a dark room. You can see the shadow of developing embryos or even blood vessels. There are charts you can use to gauge or approximate the age of the embryo, but with a blue egg as tiny and fragile as a bluebird egg I haven't risked trying it.

By the way, two of the nest boxes I put up in Virginia and had friends monitor while I was in Texas for almost a month had house sparrows move in. I got back in time to keep the HOSP population from increasing. One was immediately occupied by a pair of house wrens, but on the ground at the base of the other nestbox pole was a tiny Bluebird colored egg with a hole pecked in it. It was about the size of a Carolina Wren egg. Other than a misformed BB egg, does anyone know what else it might be?

Thanks,
Rob Barron

Lately I have been leaving inactive (?) nests for a while, in part because I always have some empty boxes available. Last year I had a chickadee nest taken over by some (pokey? lazy? late?) tree swallows. This year an apparently abandoned bluebird nest was taken by tree swallows. Probably saves them time if they are running late.

On the other hand, I have left abandoned bluebird nests in a box for the season (hoping they would come back and use it) and the box went completely unused.

With weird weather, how does one really know it's abandoned unless it's empty for about 2 months?

Bet from CT

Wedge a piece of grass or a stick in the entrance hole tight enough the wind won't blow it out but light enough the birds can remove it if they enter.
You can also lay a small twig across the nestcup. If these are not removed in two months you know the birds abandoned that "inactive" nest:-))

Seriously most of these birds will check out their nestboxes at least every couple of days and enter and check out the nest even if they are waiting for better weather to start laying eggs. If they are having to leave and travel a distance to a better food source then they may find a nesting cavity closer to this area and abandon the box on your trail or in your yard. They may find a style of nestbox they like better or a better location.

Don't forget that Carolina Wrens, chickadees, titmice and even bluebirds will eat pecans and other oily meat from nuts. Most will eat peanuts, peanut butter grain mixes, sunflower meat ETC. KK

I've been reading posts for a while now and was so excited that I had
5 eggs in my bluebird nestbox. Mom and Dad were eating mealworms from my feeder. Eggs are now 3 weeks old and about a week ago Mom and Dad disappeared. I was wondering if I just hadn't seen them, and they still were around, since I don't have a lot of time to watch. My daughter said she saw them a few days ago. Meal worms are left uneaten as well. I've seen everyone's problems...etc... and was hoping I wouldn't have any the first time around. How long should I wait before I clear the nest out, just to make sure it really is abandoned? What should I do with 5 beautiful little blue eggs? The nest is really clean, do I need to clear it completely out? What are some reasons nests are abandoned?
Thanks

Pamela Goss
Waxhaw, North Carolina

This question comes up several times per nesting season. There is no need to second-guess when to remove the eggs. There is no benefit to removing the eggs and no harm in leaving them.

Out of curiosity, did you read somewhere that you should remove old eggs?
There is a myth that removing eggs would somehow stimulate a new nesting but no one has come up with any substantiating evidence. Bluebirds are capable of removing old eggs themselves and new nests can be started over old nests.
Old unhatched eggs on my trail lose moisture and are lightweight and hollow after a couple of weeks.

As to the reason your nest was abandoned (and you don't know for sure that it is), anything is possible. Abandoned nests on my trail are very rare.
In the past, abandoned nests were caused by House Sparrow competition and harassment.

Linda Violett
Yorba Linda, Calif.

From: Paula Ziebarth [mailto:paulaz"at"columbus.rr.com]
Sent: Thursday, June 08, 2006 10:27 AM
Subject: RE: abandoned nest :(

Pamela,

A reason this nest could be abandoned would be infertility or nonviability of eggs. If the eggs were not fertilized or if the incubation was substantially interrupted due to HOSP harrassment or other reasons, the eggs might not hatch. We have had a pair on our street that has had problems this year. They laid 4 eggs in my buddy Nate's box (boy "at" end of street).
We left those eggs in there 2 weeks after hatching was due. At that point, I observed the female Eastern Bluebird (EABL) going into the box with new pine needles in her beak. I then advised Nate to remove the old eggs.

Leaving them in could have been fine, but I usually remove them when I am certain they are nonviable. This insures that the old, rotting eggs will not inadvertently rupture and cause bacterial infection of new nesting. I have never observed an EABL remove their own eggs, although others may have.
What I have observed is old eggs being pushed to edge of nest or new nest built on top. I would think they would risk rupture when trying to move them. Merely rolling them out and dropping them at the foot of the box would be a really bad move as the odor of the eggs would attract the attention of all sorts of four-footed predators.

The next day, Nate's EABL laid the first egg of their second clutch. They laid only 2 eggs and abandoned that clutch as well. We observed no HOSP interference with this box in either nesting so I believe the male was infertile.

If it were me, I would probably give it another week and observe. Gently touch eggs with back of fingers fo feel for warmth. If they are cold and you haven't seen EABL in the box, I would remove them. I leave the nest in situations like this and they almost always renest.

Paula Z
Powell (Central) Ohio

Bluebirders,

About 9 days ago, a pair of Eastern bluebirds in my nestbox abandoned
their five eggs because common paper wasps begun to occupy the nest soon
after the eggs were laid. I did not find the wasp nest until many days
later. I have rid of the wasps and put aluminum foil on the underside of the
roof so to prevent the wasps from returning. To the best of my knowledge,
she had not yet begun incubating the eggs before she abandoned the nest.
However, there was a sub-freezing cold snap here immediately after her
departure. I left the nest and eggs in the box, and today both male and
female have returned to the yard. Are the eggs still viable? Should I remove
the eggs so she may lay another brood? If so, should I remove the nest also?

Thanks,

Mark Stratton
Decatur, GA

BEST OF BLUEBIRD_L CLASSIFIEDS HOME | Audubon Society of Omaha | The Bluebird Box | Bluebird FAQs | Search | Contact me

All material was originally posted on the Bluebird_L or Bluebird mailing list, and has been reposted here with slight modifications to make the posts more readable in an HTML format.  In cases in which quoted material has been deleted to save space, this is indicated by an ellipsis (...)

For more information about Bluebird_L, check out http://www.cit.corn.edu/cit-pubs/email/using-lists/index.htm. If you wish to contact the author of a post, you will need to edit the e-mail address, replacing "at" with the "at" symbol (above the number 2 on your keyboard). (This change was made to discourage spammers.)

If you are the author of a posting and would like to see a particular post (or posts) removed from these web pages, please contact me with the web page address, title of post, and date and time of the post(s), and I will remove whatever material you like.  If you have a different opinion from one posted here, you need not contact me, as often I will have a different opinion too. The intent is to try and provide both sides to the issues facing bluebirders, and to do so in an impartial and objective manner.

If you have problems, encounter broken links (unless they are within an e-mail thread, as I do not maintain those links), or have suggestions on how the site can be improved to make it more useful, please contact the Best of Bluebird-L Classifieds webmaster. 

Website design by Chimalis