|Typical Tree Swallow nest description: Nest of grass or pine needles, usually lined with feathers. Feathers often placed to curl up over eggs. Flatter cup (about 2″ diameter, up to 1.5″ deep) than bluebirds. Occasionally contain mosses, rootlets, aquatic vegetation, and other plant materials. Some trash possible: cloth, paper, plastic, tinsel, cellophane, rubber bands, birchbark, often white.
Eggs are pure white (may appear pinkish when first laid up to 4 days) with a pointy end.
I find some nests are messier than others, and some use coarser material than others. The one on the left is fairly neat. It is in a standard NABS box.
All photos by Bet Zimmerman.
|This pine straw nest has an unusual amount of pure white feathers, laid out almost like a peony, recurving over the eggs (not visible in these photos).
|A much messier TRES nest out in Bickleton WA. Photo by Bet Zimmerman.
|Tree Swallow eggs in a completed clutch.
Notice feathers recurved over eggs for insulation. (Dottie calls them “feathers from heaven” as it’s not always clear where they come from. Sometimes they get them from domestic fowl like chickens, which can be infested with mites.)
Also notice pointy smaller end on eggs.
Early on, TRES eggs may appear pink, other times they are pure white (no speckles).
This nest is primarily constructed of straw.
|Tree Swallow eggs in a nest made primarily of straw from a barnyard.
|Tree Swallow eggs are usually a very pure white. Photo below shows how feathers often recurve over eggs.
|A TRES nest in Bickleton, WA. As sloppy as what I see in CT. Notice how the egg appears white on the larger (less pointy) end) where the air sac is located.
You can also see how pointy the eggs look on the small end, compared to bluebird eggs. Photo by Bet Zimmerman
|Some female Tree Swallows refuse to budge when their nestbox is monitored.
See photo showing two different size nestlings, possibly the result of asynchronous hatching.
|This Tree Swallow nest is made of pine needles.
A few larger feathers (Turkey, Blue Jay, etc.) are often found in TRES nests.
|TRES eggs in cup of downy feathers, with larger feathers curving up over top of the eggs.
|TRES nestlings, maybe a couple of days old.
|“Clown lips” (as Tina Mitchell calls them) evident on these TRES from Bickleton WA. Eyes beginning to open. Notice difference in size, often due to asynchronous hatching.
|TRES nestlings. Eyes are opening up.. I usually don’t see TRES gape when I open a box, but yesterday was a cold rainy day, and they may have still been hungry today.
|TRES nestlings. These chicks are at least 11 days old. They hunkered down totally when the box was open.
|Just three in this Gilberston box. Exact age not certain, but they are at least 2 weeks old.
|TRES nestlings. The brown thing on the wing of the second bird from the left is a flying insect.
TRES parents stop removing fecal sacs around day 14, but the babies don’t fledge for another week, so the nest can get pretty nasty (see photos at the bottom).
|TRES nestlings. The one is the middle is piled onto another nestling. The one on top looks a lot bigger than the others, but it might be an optical illusion. However, some young do “hole hog” and get more than their fare share of feedings, and thus might grow more quickly than others. I have also seen evidence of possible asynchronous hatching – see photo. This could happen because TRES start incubating on the penultimate (next to last) egg.
|Same nestlings as above, one week later. They look pretty close to fledging, but certainly showed no signs of budging when I disconnected the Gilbertson box from the roof to monitor.
|After fledging, TRES nests are pretty skanky because the parents stop removing fecal sacs around Day 14, but the young don’t fledge until around Day 18-22. They may also be filled with mites transported on the feathers used to line the nest cup.
The basic rules for studying nesting birds, therefore, are as follows: disturb as little as possible; preferably examine nests only when the owners are absent; be as quick as possible; and at all times exercise the greatest care and caution, remembering that a little carelessness can bring about the accidental destruction of nest and brood.
– A Guide to Nests, Eggs and Nestlings or North American Birds, by Baicich and Harrison, 1997