Date: 4/19/17 2:39 pm From: David Waltman <djwaltman...> Subject: Re: [cobirds] The ongoing saga of the Boulder County phoebes
I know at least three bridges in Boulder County with phoebes. Which bridge are you talking about?
----- Original Message -----
From: Charles Hundertmark <chundertmark8...>
To: <tedfloyd57...>, Cobirds <cobirds...>
Sent: Wed, 19 Apr 2017 21:00:22 -0000 (UTC)
Subject: Re: [cobirds] The ongoing saga of the Boulder County phoebes
I stopped by the bridge this morning. Shortly after I arrived, the Black Phoebe flew out from under the bridge. Seconds later, the Eastern Phoebe flew out. Shortly, both went under the bridge again, and flew out after an interval. They seem to be a pair.
As Ted indicated, the range extensions of both of these species in Colorado raises interesting questions. With Black Phoebes moving north and Eastern Phoebes edging west, will one species out compete the other, since they both seem to favor bridges or other human-made structures for nesting sites? Will they segregate on some microhabitat characteristics? Or, as Ted asks, will they hybridize? To what extent will they compete with Say’s Phoebes that sometimes favor similar nest sites?
The selective process may play out quickly (several bird generations) or over a longer time (human generations). No need to go to the Galapagos Islands. Colorado becomes an ever more interesting evolutionary biology lab.