ACES Morning Birding at Hallam Lake 09/08/2026

Fall migration brings on exciting days here and there, and today was particularly fun! We saw many regular Hallam Lake birds, some of which have gathered into impressive flocks, like pygmy nuthatches, pine siskin, and evening grosbeaks. And we enjoyed some fun surprises: a Wilson’s snipe in the water channel, a dipper in the very low-flowing Roaring Fork River, and a small flock of Brewer’s sparrows in the bullrushes on the lakeshore. But the biggest excitement of the morning was finding two sharp-shinned hawks in the cottonwood canopy above the golden eagle’s aviary. These two accipiters were alternately being chased by and chasing several Steller’s jays and magpies that were mobbing the hawks. As bird-eating specialists, the sharpies represent a predator threat to these corvids, even though they are basically the same size and sharpies generally eat songbirds such as chickadees and juncos. The corvids harassed the hawks, causing them to move about from perch to perch. In return, the hawks aggressively chased the corvids… This went on for a full 20+ minutes, while we were riveted as we watched carefully for the field marks we needed to see to identify the hawks. Eventually, with views of the tail (squared off instead of rounded), legs (very thin, pencil-like), head (eye placed roughly  in the center, front-to-back; as opposed to toward the bill), and overall size being similar to that of the Steller’s jay (as opposed to much larger)… we were able to land on sharp-shinned as an ID for these birds (as opposed to the very similar, but larger, Cooper’s hawk). We did seem to notice the possibility of a third hawk that seemed larger, possibly a Cooper’s, but we ended up focusing on the two sharpies which we observed for an extended time and with excellent views. These sharp-shinned hawks were both juveniles, with vertical, brown streaks on their underparts and pale irises, possibly nest-mates dispersing from their natal site. This was a very rich group learning experience, as we noted our observations, consulted the guidebook, debated, and questioned. One member of our group was a photographer, who grabbed many great shots of these birds for later analysis. Finally, our Merlin app picked up a sharp-shinned hawk vocalization, helping to boost our confidence and a round of high-fives. Join us for several special fall field trips coming up this month: Difficult Campground on the 10th, Hunter Creek on the 14th, a private property on Capital Creek on the 17th, and Ranch at Roaring Fork on the 24th!