Nest Check, June 15, 2008

Cavity nesting birds are doing well, for the most part. Weather has been cooperative, and the insect population is up. Cicadas are a good food for the adult martins, but too big for the babies or for swallows and bluebirds, I would imagine.

The 4 Tree Swallow nestlings are 14 days old and hanging out of the front door, taking their first look at the world. I approach cautiously and don't get too close, for fear of spooking them out of their safe home too soon. They will fledge sometime this week.


The 3 Eastern Bluebirds are 8 days old today. This isn't the greatest photo of a bluebird nestling, but you do get a good look at the emerging feathers.


Several Purple Martin nests have hatched in the last 2 days. I currently have 19 young between the ages of 1 day and 12 days old, and 32 eggs. Here is a look into Gourd #21, which contains 5 newly hatched martins.


Adult Purple Martins are 8 inches long. The chicks come out of an egg smaller than a quarter, and have to reach their adult size in one month. Here is a photo of two halves of an egg from the hatchlings in #21.

It is rare that I find the shells, and especially rare to find both halves of one, as the adults usually either eat the shells for the calcium they contain, or discard them far away to discourage predators.

On the down side, I seem to be having more egg losses than normal. I had 1 infertile egg in the Tree Swallow nest and 2 bad eggs in the bluebird nest, one that she rejected and one that didn't hatch. Among the Purple Martins, egg losses are always higher than with my other cavity nesters, but I think this year is worse than last. I have lost at least 12 eggs to date - 5 pecked by House Sparrows and 7 to damage, infertility, or eggs that were lost (I think) during high winds in a thunderstorm.

This is my first attempt at uploading video. I thought you might like to experience a bit of what I go through during a nest check. This is about 65 seconds of me standing under the gourd rack after a nest check. I have just raised it, and the adult birds are returning to their homes. [Please ignore the paint peeling from my natural gourds. I put off doing my cleaning and repainting chores until it was too late.]




Unfortunately, I didn't capture the times when I was dive-bombed by martins. If you have ever been dive-bombed by a Tree Swallow, multiply the effect times 10 and you can begin to appreciate what it feels like to have an 8 inch martin swooping toward you at what seems like 90 miles a hour. The final "SQUAWK!" as the bird pulls up only centimeters from your head is enough to make you shiver. Imagine what it must be like to be a bird and have a peregrine diving toward you!

Babies, part 2

Has it only been 5 days since we last looked in the nest boxes? I guess so, but you couldn't tell it by how fast my babies grow.

Compare these photos to the baby bird pictures seen here:

Eastern Bluebirds, 5 days old, in the nest

and in hand.

Purple Martin chick, 11 days old

Compare the development of the above 11 day old Purple Martin with this 11 day old Tree Swallow:

Look at all those feathers! This box was full of fine white powder from the shafts of the pin feathers breaking open. Not so oogly now, eh sis?

nest box full of Tree Swallows

This will be the last time I can handle them. Tree Swallows fledge in 16 to 24 days, average about 20 days, which is similar to bluebirds (16 to 21 days) so I use the same rule of not opening the next box after the 12th day. Don't want to cause premature fledging, do we?

This guy wants to fly already!

Oh, and the "surprise" martin nest, the one with the mud dam nearly filling up the 6"x6" aluminum compartment? It has 2 eggs today. Woo-hoo!

Babies

My back yard nesting boxes are full of eggs and babies. Here are a few images from this weekend.

One day old bluebird

6 day old tree swallow

6 day old purple martin

Despite the successes, I am having some unexplained losses. Of 5 tree swallow eggs, 4 hatched, one was infertile. Of 5 bluebird eggs in this second clutch, she rejected one and only 3 of the remaining 4 hatched. This is odd for me. I usually have 100% hatching rate in bluebirds.

In the purple martin department, there are currently 10 nests with eggs. I have lost 7 eggs from various nests. Two were blown out during the bad storms, and others were either damaged or infertile, or have just gone missing.

I have two nests with young; 5 nestlings from 5 eggs in one gourd, and 2 nestlings from a clutch of 4 eggs in another.

There are two nests that I call "bachelor pads." These are spaces occupied by subadult males without a female. The boys have done some minor decorating, but haven't really gone all-out in furnishing their homes.

And then, there is this nest:


This is a small compartment (6"x6") in the metal house, with a round entrance hole. It is on the back side of the bird house, so I can't see it easily from the window, but I think an ASY male has taken it over. The mud dam in front effectively narrows the 2.5" round opening to something approximating my crescent SREH holes, and acts as a way of protecting the contents from starlings and owls. However, despite all this effort, I have yet to see a female associated with this compartment. It is unusual for males to do more than initiate the nesting effort, leaving the bulk of the work to the females, so there could be a lady living here. Time will tell, and I keep checking for eggs.

Rejected, Protected

Just when I think I know everything there is to know about bluebirding, I learn something new. Today, for the third time in a row, when I opened the front of the nest box I was greeted with this image:


The first time I saw an egg out of the nest cup and up against the front panel of the box, I thought it must have been jostled out by mistake, and I gently rolled it back into place. The second time, I began to wonder if there was something wrong with the egg and it was being rejected, but I erred on the side of caution, and replaced it into the nest. The third time, it was obvious that Mama Bluebird doesn't want this egg for some reason.

This is the first time in 15 years I have seen a bluebird reject an egg. I haven't removed it from the box, just in case, but I highly doubt it will hatch. How does she know?

These are the times I wish I had a nest cam, to watch what was going on inside the box. I imagine Mama B struggling mightily to move this object up and out of the nest. "I told you - umph, ha, oof - that I don't want - erg, hmmm, aah - this thing - huff, puff - in my - ooh, ow - nest. Now, stay out!"

On the other hand, Mrs. Tree Swallow has filled her nest with so many feathers, you can't see anything else. Just 9 days ago, I captured this image:

Today, this is my view:

Baby Tree Swallows, are you in there?

Purple and Blue All Over

I spent some time sitting quietly under an apple tree today, watching all the action going on at the various nest boxes and gourds. The main goal was to sort out the ages and sexes of the martins nesting in the gourd rack. I am trying to figure out how many are ASY (After Second Year) birds and how many are SY (Second Year.) There were too many distractions to get a complete count, but I did get some photos to help you see the differences.

[Aside: The year the young are hatched and fledge is their Hatch Year. They migrate to South America for the winter, where they molt, and return the next year as subadult or SY birds. This is their second summer, or their first breeding season, and they are basically teenagers. They migrate again that fall and acquire their adult plumage, returning as adult or ASY birds.]


This is an ASY, or adult male Purple Martin. He's the easiest to sex and age - he's purple all over. You can see how the species got its common name. Isn't he gorgeous?


I have seen at least 3 ASY males so far this year, maybe more. (Won't everybody just line up and sit still for a head count, please?) Last year's colony was started by one ASY male, so at least two of these guys are probably my SY's from last year, all grown up and come back home from South America.

This is an ASY female. She has some purplish coloration on her head and back, but her breast and belly are pearl gray.


Another ASY female. An SY female would have a whiter breast, but the big key to distinguishing subadult from adult females is the undertail coverts (feathers under the tail.)


Here is a close-up of the undertail coverts in this ASY female. In an adult female, the feathers have a gray center. In a SY female, they would be all white. I haven't seen an SY female yet, so I don't have a photo of one for comparison.


An SY male. Subadult males look an awful lot like adult females, which is one reason why my census is going so slowly. Look for a dark throat and irregular purple blotches on the breast and/or belly to ID a subbie male. If you can hear one sing, that clinches the ID, since females don't sing, but there is a lot of noise in a martin colony, and it can be hard to tell who the songster is.


I have been a bit lax in my martineering duties so far this spring, and today was my first complete nest check. Imagine my surprise to find that all 12 of my main gourds have nests and three of those have eggs!

Martin nest.

Notice the mud dam in front of the nest cup, which is lined with green leaves. I find martins make these barriers in the larger plastic Super Gourds.

Martin nest with 5 eggs in a natural gourd.

I also have a pair of martins interested in a Super Gourd that is hung on a shepherd's crook (the one that was intended for tree swallows and where I trapped a starling.) I'm surprised they would choose to nest so low, but all the prime spots are taken. I have seen 3 different martins exploring the aluminum house, but as far as I can tell these are all bachelor subbie males.

[Aside: Most colonies end up with extra SY males. These boys hang around the colony, trying to usurp already attached females. Juvenile males are the same all over the animal kingdom, always causing trouble.]

The Tree Swallow couple has five eggs.

This is the best look I can give you of the female.

The male isn't shy about being photographed, though.

The bluebird couple has a new nest, which looks to be nearly complete.

I haven't seen the fledglings from the first clutch yet, but I got some great pictures of Papa today.

Please indulge my bluebird addiction:

One last photo of an adult male Purple Martin.

And, for the ultimate in nestbox cams, go here to see the Columbus, Ohio, peregrine falcons. Live streaming video of Orville and Scout's clutch of 4 babies.

Baby Bluebirds Have Fledged

And here's what's left in the nest box after the young ones take wing...

Ugh! This is what greeted me when I opened the bluebird box on Thursday. Hard to reconcile this messy debris with the beautiful nest full of babies that we last saw. I need to scrape out all this old nest material, brush the walls and floor down with a wire brush, and pour boiling water through the box to clean and sanitize it for the next clutch.

This is what happens when you neglect your trap box for too long:



A House Sparrow builds her nest and lays her eggs. Horse hair, plastic trash, baler twine, dried and fresh grasses, and these spotted eggs are classic. After trapping and removing the female, I removed the eggs and nest, too.

Next nests to monitor will be Purple Martins and Tree Swallows. Updates soon.

Newly returning migrants: Barn Swallows came back this week.

Baby Bluebirds: Last Photos

Bluebird fans, these will be the last pictures of the first clutch of 2008. So, drink in these images, there will be no new bluebird photos for a while. (Read on for the reason why.)

Nine days old and 5 nestling bluebirds hide their faces,
hoping I won't notice them.

As you can see, I took the nest out of the box for this family portrait. It doesn't seem to cause any problems when I do this, but it makes me nervous, so I only do it once or twice.

"Has she gone yet?"

Wow, the last few days have just flown by, and we are nearing the end of the baby bluebirds' first stage of life. Remember my first bluebird post this spring, when I said there were some times when it wasn't OK to open a nest box? Now, we come to the time when we have to stop open-box monitoring, Day 12.

Day 11, and they are looking more like birds.

"Get this piece of grass out of my face.

It is blocking my good side."

All three of my bluebird references* advise not opening the nest box after the young are 12 days old. The concern here is that you may cause premature fledging. Once a baby jumps from the nest, it is nearly impossible to get it to stay there no matter how many times you put it back. I have never had a problem with premature fledging in bluebirds, but I nearly had a disaster with Purple Martins last summer. (Read about it here.)

12 days old, a touch of blue in the wings
"Fledge well and prosper, little ones."

*My bluebird references? First and foremost, "The Bluebird: How You Can Help Its Fight for Survival," by Lawrence Zeleney; Audubon Naturalist Library, copyright 1976, by Indiana University Press. I think this book is out of print now, which is too bad. Mr. Zeleny could easily be called the "father of bluebirding," and was (I think) the guy who invented the term "bluebird trail."

The "Stokes' Bluebird Book" is an excellent reference on the care and feeding of Eastern Bluebirds (also the Western and Mountain species get their own sections.) It follows the classic format of many of the Stokes' guides, and of course, has stunning photographs.

And last but not least, I have a little 30 page booklet called "Enjoying Bluebirds More." It was published in 1993, and I don't know how long I have owned my copy, but I'm sure it has been for at least 13 years. I pulled it out last year, because I remembered it had instructions on making a stovepipe pole baffle, and happened to notice the author's name: Julie Zickefoose. Huh, that lady seems to know a little bit about bluebirds. I'll bet she'll go far!

Baby bluebirds grow so quickly

I hope you are enjoying watching my baby bluebirds grow.

Here they are at 5 days old

and 6 days old.

And here they are today, 7 days old.

The feather tracts are becoming obvious

and the primaries are erupting along the wing.