Mlodinow and Leukering (2018) wrote a fantastic and informative piece in Colorado Birds about identification of Western and Clark's Grebes along with thorough discussion of hybrids. Not sure if this link will work, but try this:
https://cobirds.org/Publications/ColoradoBirds/InTheScope/84.pdf Adam Vesely Thornton, CO On Sunday, April 11, 2021 at 11:20:26 AM UTC-6 Mark Minner-lee wrote: > If anyone has been out to see the Western and possible Clark’s Grebes at > Stern’s Lake (Boulder County) I’d love some thoughts on how you determined > a Clark’s ID. Additional commentary also welcome from others who would like > to lend their expertise. > > The two grebes I saw both fit Western or Intermediate but not Clark’s. > Flanks on both birds were dark (suggesting Western). Bill color wasn’t > different. Both birds had eyes clearly with the dark supercillium area, > with the suspected Clark’s having some white in the lores. > > Thoughts? > > Regards, > > Mark Minner-lee > Erie, CO > > Sent from my iPhone -- -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to cobirds@googlegroups.com For more options, visit this group at http://groups.google.com/group/cobirds?hl=en?hl=en * All posts should be signed with the poster's full name and city. Include bird species and location in the subject line when appropriate * Join Colorado Field Ornithologists https://cobirds.org/CFO/Membership/ --- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to cobirds+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/407f4ab8-3c63-403a-9247-735707088becn%40googlegroups.com.