qwerty5
Controversial opinion generator
I've observed Bank Swallows quite a bit this spring and I've noticed some ID points that may be helpful to some.
First of all, the Bank Swallows I've observed were foraging low (3-20 ft above ground), and I've found that the chest band is very difficult to see, even with a view of the underparts. The chest band is the classic Bank Swallow field mark, so here are some other characteristics I found useful for separating from Northern Rough-winged Swallow, the only other brown-backed swallow.
1: Clean white belly. The belly and chest is bright white, like Tree Swallow bright. Northern Rough-winged Swallows do not have a bright white belly, it is much duller.
2: Pale back contrasting with wings. The lower back and rump are contrastingly paler than the wings, a mark that Northern Rough-winged does not show
3: Shape (and size?): The shape of Bank Swallow is quite thin with thin wings and a thin tail, while Northern Rough-winged is much bulkier. Bank is smaller than Northern Rough-winged, and Bank appears small to me, smaller than Barn Swallow. I assume that the small appearance is due to the shape making it appear small, since size is not supposed to be reliable, especially on a flying bird.
4: Dark area on auriculars. From the right angle, a dark bar or line is visible towards the front of the neck, probably the back edge of the auriculars. I've found that the white curling up from the breast onto the neck is not easy to see, but the contrasting dark line is easy to see.
First of all, the Bank Swallows I've observed were foraging low (3-20 ft above ground), and I've found that the chest band is very difficult to see, even with a view of the underparts. The chest band is the classic Bank Swallow field mark, so here are some other characteristics I found useful for separating from Northern Rough-winged Swallow, the only other brown-backed swallow.
1: Clean white belly. The belly and chest is bright white, like Tree Swallow bright. Northern Rough-winged Swallows do not have a bright white belly, it is much duller.
2: Pale back contrasting with wings. The lower back and rump are contrastingly paler than the wings, a mark that Northern Rough-winged does not show
3: Shape (and size?): The shape of Bank Swallow is quite thin with thin wings and a thin tail, while Northern Rough-winged is much bulkier. Bank is smaller than Northern Rough-winged, and Bank appears small to me, smaller than Barn Swallow. I assume that the small appearance is due to the shape making it appear small, since size is not supposed to be reliable, especially on a flying bird.
4: Dark area on auriculars. From the right angle, a dark bar or line is visible towards the front of the neck, probably the back edge of the auriculars. I've found that the white curling up from the breast onto the neck is not easy to see, but the contrasting dark line is easy to see.
