Every evening I watch a flock of between 10-20 birds seeming to soar over the area collecting bugs but I dont know for sure which. Is there a way to ID the difference if they are collecting bugs/mosquitoes.
Sparrows are mostly seed eaters, though they do eat bugs as well - typically NOT by catching them on the fly, however.
Soaring birds catching bugs on the wing are likely either swallows/martins, swifts, or goatsuckers (ie nighthawks, whip-poor-wills, chuck-wills-widows, etc.). The last group are mostly active at dusk and into the night; chimney swifts and swallows are more active in the day and evening.
if the birds have narrow, cigar-shaped bodies with long, thin pointed wings - they'll look something like a boomerang stuck on the body - then they're probably swifts. If the birds are a bit plumper, with slightly broader wings, and a tail that's spread much, then they're probably swallows.
By this point, martins are already massing into flocks to being southbound migration, but there are many other species of swallow that it could be.
Yes it should have been swallows or martins. I sometimes see barn swallows but I see those during the day and they are larger than the ones in question and not very often here. The birds in question are seen every evening at dusk and probably more in the flock than I first mentioned.
Heat zone 6
Sunset zone 35
This message has been edited by Stevenindy on Aug 11, 2012 11:06 AM
I am with Kevin. One way to know is to watch their wingbeats, if they seem kind of out of sync, not perfectly timed, then they are Chimney Swifts. The out of sync is an illusion but it sure looks like it. They are coming to roost in some old chimney or hollow tree near you.
The way I mentally describe Chimney Swift wingbeats to myself is, they look like "twinkling" - I can't say WHY that word comes to mind, but it does. Swallow wingbeats seem more regular, somehow.
I'm familiar enough with the body shapes to be able to distinguish them that way now, but just a quick glimpse of the wingbeat (as you note) is enough, too. I guess it's one of those things that comes with experience.