Ibis at Cottonwood Marsh, Boulder County

[Peter Burke]

CoBirders,

I observed a juvenile Glossy/White-faced Ibis this morning at Cottonwood Marsh in Boulder County. The bird appeared overall dark to me, with no noticeable white marks on the face, grayish bill and legs. At that point a hunter's gun flushed the bird along with many ducks and a few Greater Yellowlegs.

It briefly landed on an island giving me a chance to see it in close detail in the morning sunlight. I could tell it had a dark, not red, iris. A few more gunshots and the bird was gone, but I felt confident it was a Glossy - based on the dark eye.

Hearing that David Waltman had re-found the bird, I went back for further study. There's a note in Sibley next to 1st winter White-faced Ibis that says, "iris red by Feb." I wasn't aware that a juv. White-faced would also have a dark eye at this time of year... Without that mark to differentiate the two species, I'm not sure this bird can be identified reliably. I've updated my eBird list to Glossy/White-faced.

Other late-ish birds on this glorious October day were three Long-billed Dowitchers at Teller Lake.

Good Birding,

Peter

Peter Burke

Editor, Colorado Birds

Colorado Field Ornithologists

935 11th St. Boulder, CO 80302

(973) 214-0140

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