Re: [cobirds] Lesser or common nighthawks?

Thanks for the photo, which is of a flock of Common NIghthawks, Marcia.

A field mark that is useful is the shape of the triangle formed

by the white bar and both edges of the wing tip. In the photo

that triangle is isosceles, as Common NIghthawks show), vs the equilateral triangle that Lesser Nighthawks

show. That can be hard to see in the field, so the photo helps a lot.

Plus Lesser Nighthawks occur in CO as singletons (up to two at favored sites

like the Nucla Sewage Ponds, where they are almost annual); the east slope flock of twenty you saw is a common occurrence

for migrating Common NIghthawks.

Those photos are actually good at sorting out the two species.

Joe Roller, Denver

On Fri, Jul 24, 2020 at 5:41 PM Marcia Wade - Lafayette, Boulder County <marciaewade@gmail.com> wrote:

I observed a flock of what I believe to be lesser nighthawks July 23rd at about 9:00 p.m.over the Aquarius Trailhead on the Coal Creek Trail. There were about 20 of them, and they swooped around the fields on the south side of Highway 42 (Empire Rd.) for fewer than five minutes and then flew off, heading southest.  The pic attached is really bad, being as it was almost completely dark when I took it, but the white stripes on the wings are plainly visible, and appear to be too close to the wing tips to be common nighthawks, although the wings seem pointier (if there is such a word) like a common nighthawk's.

    

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