While trying to keep up my eBird-checklist-a-day for the month of January, I noticed an interesting swallow in a flock of ~25 Tree Swallows (TRES). Of course I did not have my camera with me, so no photos. I don't have a huge amount of experience with either Cave or Cliff Swallow (Petrochelidon sp.). I realize that Cave is the more likely species, but for now I'm calling it a swallow sp.
Other codes used below: Northern Rough-winged Swallow (NRWS) Barn Swallow (BARS)
Petrochelidon sp. While observing and trying to count a flock of TRES with the naked eye, I noticed a swallow with a paler rump. When the bird circled back around, I also noticed a pale "collar" that stood out. I eventually sighted the subject in my binoculars (8x42) and noted the following field marks: blue/black upperparts (not brown); paler, rusty rump that contrasted with the darker back and tail; forehead had a rusty/rufous patch with no white markings observed; the terminal margin of the spread rectrices was virtually straight compared to the slightly notched tails of nearby TRES; not a lot of contrast between crown, auriculars/face and throat with strong contrast between pale "collar" and the rest of the head, which appeared almost hooded. I recognize that this feature could be an artifact of the overcast/low light levels at this time of the day, but the contrast between the white throat and the rest of the head was clearly visible on the nearby TRESs. Separated from TRES by pale/rusty rump and rusty/rufous markings; from NRWS by lack of brown upperparts; from BARS by straight edged rectrices.
I am planning on trying to re-find and photograph the swallow around 4ish on Wednesday. If anyone is interested, you can contact me off-list for directions. If you do come out, wear amour for protection against the fierce Muscovy hoard!