ACES and Pitkin County Open Space Birding 8/26/26

Fall migration is always exciting as birds pass through the area over a period of several months. The presence of birds in adult breeding, non-breeding, and juvenile plumages makes identification a more complex (and fun!) puzzle. Comparatively, spring migration is a more compressed phenomenon as birds (mostly in adult, breeding plumage) are motivated to race to prime breeding territories and claim them. Today’s bird of the day was hands-down a chestnut-sided warbler in non-breeding plumage, observed for many minutes in a shrubby patch across the river. Our bird flitted constantly among the foliage and bare branches, up high, down to the ground, and even to rocks at the edge of the river. We saw this bird for brief moments, in all kinds of lighting conditions, noting its white eyering, golden crown and distinctive chestnut-colored markings on its flanks. Catherine Hagen, a participant, captured diagnostic photos to include with the eBird list for documentation. This bird itself was a thrill to encounter, but the ID process that our group experienced was also remarkable. Each of us contributed information as we found and re-found the bird, helped others find it, and shared the colors and patterns we noticed. We paged through the guide book to find the likely warbler candidates that fit with certain field marks, and eventually saw the diagnostic chestnut marking on the flanks for a 100% confident ID. High-fives were slapped as the group shared the thrill of finding the bird, keeping on it, and working through the ID process. We also realized that this was just one rare bird that we happened to spot, and that there are likely many more out there! Aside from that, we enjoyed seeing red-tailed hawks, a family of ospreys, a family of kingfishers, many turkey vultures, a few dippers, and other birds that we typically see in this area. The open space properties in the lower gorge of the Roaring Fork River are important bird habitat throughout the year. Join us tomorrow for more fall birding at North Star and Friday at Snowmass Village’s rodeo ponds and wetlands!