Tree Swallows

[Brenda]

While I was doing some research/refreshing on determining the ages of female tree swallows, I came across an interesting tidbit. According to Cornell, the tree swallow is the only swallow that makes substantial use of seeds and berries (particularly bayberries) when insects aren't available! I was taught otherwise, but it just goes to show you that you should always question. When I was responsible for banding and collecting data on the 50+ nest boxes throughout the national forest, I found more than one pair of tree swallows dead in the boxes in the early spring. It had to have been during an extreme cold spell when the temperatures killed the birds rather than the lack of food?

I now only monitor the nest boxes on my property. We keep a TV antenna up so that we can still get local channels when the satellite is down, and the swallows (and hummingbirds) use it as a perch. As you can see from the following photos, they're totally unphased by my presence on our back deck.

In this photo of one of the females, you can clearly see the dusky brown of her head, as well as her brood patch, which acts like a hot water bottle when she's incubating her eggs.



This is her mate. Note the solid blue-green coloring on his head.



Just a photo of the pair. I believe that she is an AHY (after-hatch-year) female.



They were having a lively discussion in this one.

[Matt]

very interesting.

[Brenda]

I went out to check activity in my nest boxes earlier. I only have 3 boxes up right now, of the size that will accommodate tree swallows, bluebirds, house wrens, or chickadees (house sparrows too, but I tear their nests out as soon as I see them). One box was empty. It needed a predator guard, because something had enlarged the opening, and my husband just added one, so that should make it more attractive. The second one has a tree swallow nest, but no eggs yet. I did note that it wasn't the nicest nest that I'd ever seen, and I have to wonder if it's because it's her first time (if it's the young female photographed above). The third box has a bluebird nest with 3? eggs. I startled her off the nest, so I didn't want to spend too much time there. Bluebirds are much more sensitive to disturbance, so I won't check that box again until I know that the young have fledged (since I didn't note when the eggs were laid, and I'm not banding). Bluebirds, like robins (same family-Thrushes), can nest twice within a season. Tree swallows typically have one shot at it. They may nest a second time, if the first nesting wasn't successful, but if the young haven't fledged by the time that the adults begin to molt, prior to migration, the chances of survival are slim.

[Brenda]

I checked the nestbox that the tree swallows had started building in, a few minutes ago, and while it appears to have been tidied up a bit, there are no eggs yet. I took this photo just to illustrate the basic features of a tree swallow nest. It is always a cup of dried grass lined with white feathers. When I checked the box the other day, there were a few darker feathers mixed in, but they seem to have been replaced. One website that I visited recently indicated that you can go out to a nest box where tree swallows are nesting and throw white feathers in the air (from approx. 20 ft. away), and the birds will swoop down and fetch them. I personally, have never had that much time on my hands, but it's not the first time that I've heard that and it would be neat to see.

[Brenda]

Well, the one nest box that had a tree swallow nest in progress was taken over by house sparrows. It's easy to tell a house sparrow nest because they use pieces of plastic or whatever other trash (approriate for the species) they can find to weave in with the dried grass. I tore the nest out, and scattered the white feathers that the swallows had collected, hoping that they'll reuse them wherever they decide to rebuild. The pair is still around (there was a little hanky panky going on in the back yard today), so hopefully they'll rebuild in one of the two available boxes.

Because house sparrows are a non-native species, which compete with our native cavity nesters, it is legal (and encouraged) to remove the nests and discourage the birds by any means necessary. When I was active in banding, Cornell advised me to boil the house sparrow eggs and replace them in the nest so that the birds would continue to incubate, rather than rebuild. I personally prefer to just tear out every nest of theirs that I find before they start laying eggs.

[Brenda]

They're back! We just spotted our first pair this afternoon.

[Brenda]

One pair opted for a condo over a single family unit this year! The martin house is on a telescoping pole and we had just lowered it and covered it for the winter, but we neglected to block the entrances when we uncovered it. I guess the new coat of paint is going to have to wait for now. I tried to get a better/closer shot, but then I pissed off the female and she started diving at me.

[skiboarder72]

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