Date: 4/18/17 1:56 pm From: Ted Floyd <tedfloyd57...> Subject: [cobirds] The ongoing saga of the Boulder County phoebes
I stopped by the Walden Ponds area, Boulder County, earlier this Tuesday, Apr. 18, where I saw two phoebes along Boulder Creek near the 75th St. bridge. One was a *black phoebe,* probably the bird present there since late March. Also present was an *eastern phoebe* gathering nest material and taking it under the bridge. I wonder if the black phoebe is the eastern phoebe's mate; I detected no other phoebes at the site. Actually, that's not true. There was a *Say phoebe* in the general vicinity, but it was away from the creek, in the dry uplands south of the creek, closer to Cottonwood Marsh.
There was a time, not all that long ago, when any Boulder County phoebe other than a Say phoebe was noteworthy. Now we have multiple occurrences of mixed-species detections on creeks and rivers in the counties. For sure, we should be on the lookout for hybrids. Nathan Pieplow has published on what to look for--and, in particular, what to listen for--when we're dealing with hybrid phoebes. With both species expanding their ranges in Colorado, it will be fascinating and important to see if hybridization becomes extensive.
Also at Walden Ponds this morning: 5 *wood ducks,* 1 *white-faced ibis,* 2 *broad-winged hawks,* *northern rough-winged swallows, yellow-rumped warblers, Gambel's white-crowned sparrows,* and a *savannah sparrow.*
Here are the Boulder Creek phoebes (Eastern, left; Black, right):