Do swallows of different species huddle together?

[Julie Brown]

The bird on the left is a Barn Swallow? but is the bird on the right a Bank Swallow? Would swallows of different species do this?
Image shot from Antelope Island Causeway on 10/8/11.

[John Chardine]

Hi Julie- Unlikely. I would guess that this is a parent and a fledgling Barn Swallow.

[Julie Brown]

Thanks John. I was confused by the lack of rufous coloring on the throat.

[Dave Irons]

Julie,

These birds are indeed of two different species. Given the date (mid-October) I'm guessing that these birds are huddling together to stay warm. The bird on the left is a Barn Swallow, while the bird on the right appears to be a hatch-year Tree Swallow. In all plumages, even very young juveniles, Barn Swallows have a paler forehead not a uniform colored crown and forehead like this bird. Additionally, young Barn Swallows have a complete or mostly complete band across the breast. Young Tree Swallows, which are dusky brown above (similar to a Bank Swallow) are often confused with Bank Swallows because they can look like they have a breast band. They generally have a darker wash on the sides of the upper breast (like this bird) that from certain angles may look solid and as though it connects across the breast. Note on this bird how the top half of the head is pretty solid dark and then transitions pretty cleanly to a whitish lower face and throat. On a Bank Swallow, particularly a young one, the transition on the lower face is not so straight across and the white on the throat wraps up behind the cheek onto the sides of the neck.


Dave Irons
Content Editor www.birdfellow.com

[Julie Brown]

Hi Dave. That is really interesting. I am familiar with tree swallows, but I have not seen enough of them at different stages. Thank you so much for that additional information. I really enjoy learning about behaviors, and various plumages.

[John Chardine]

I'm glad I said "guess". Thanks very much for the swallow plumage detail Dave. Attached is an image of Barn Swallow chicks and indeed they do have light foreheads.

What confuses me in Julie's image is the prominent white throat patch on the right hand bird that in no way is a similar tone to the breast. None of my field guides show this for Tree Swallow immatures - maybe the breast feathers are stained?. Sibley shows a dark-buff band across the upper breast of immature Trees whereas the right hand bird really doesn't show this (I tried to make it into one but couldn't). The righthand bird shows a light throat patch rimmed with darker feathers, then a patch of greyer feathers, followed by a broken thin band of darker feathers, finally followed by a dirty, rusty breast.

I am still struck by the apparent social attachment of these two birds. I'm just throwing this out as an idea but it is known that swallows hybridise. What if ...........?

[Julie Brown]

Nice shot of the chicks, John. Interesting points you made here. I am intrigued regarding the possibility of hybridization. There was actually a third swallow with these two, but it did not stay as long. I first saw them from behind, then walked around them to get this view. I will look at the images again to see if the other bird can be identified.