White-throated Swifts dance at evening in JeffCo - DFO trip added 10/7

[David Suddjian]

Some know of the cliff on the Lyons Formation hogback overlooking Deer Creek in JeffCo where White-throated Swifts nest. They nest in the cliff in small numbers of less than 10 pairs, but migrants visit the same cliff in larger numbers and roost in its large crack and use smaller spots there, too. Numbers are greatest in the late summer and early fall. The roosting action has been going on for weeks, but soon will end. Here is my checklist from Friday evening, presenting some of the detail when some 445 White-throated Swifts were at the roost.  https://ebird.org/view/checklist/S60352815  

Forgive my poor digiscoped images but they give a taste. A most lovely element is the swift shadows playing against the cliff, cast by end of the day sun as the birds fly at the roost. 

I have added a DFO field trip for a small group to join me for the evening on Monday Oct 7. There is no guarantee they will still be there, as they will depart soon, but there is a good chance, I think. Details and registration are here: 

https://dfobirds.org/FieldTrips/UpcomingTrips.aspx  

David Suddjian

Ken Caryl Valley

Littleton, CO

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