You both may already know the info in the below Cobird (bird postings in CO) emails. I did not know the #1 and #2 host species for Cowbirds were the Yellow Warbler and Song Sparrow. Yipes!
> On Jun 27, 2016, at 12:20 PM, Jim Nelson <[email protected]> wrote: > > Brian, > > It is interesting to see how many different species raise Cowbird chicks. > According to the species account in Birds of North America Online, one > comprehensive source found that Yellow Warblers are the most frequent host > species for Brown-headed Cowbirds. At home here in Maryland, I see Song > Sparrows (which are the number two most frequent host species) feeding > Cowbird chicks in our yard every summer. > > The largest size disparity I have ever witnessed was a tiny Ruby-crowned > Kinglet feeding a significantly bigger Cowbird chick in Rocky Mountain > National Park. > > Jim Nelson > Bethesda, Maryland > > From: [email protected] > Sent: Monday, June 27, 2016 1:49 PM > To: Colorado Birds > Subject: [cobirds] Yellow Warbler and Cowbird, Arapahoe County > > Today while walking along my favorite part of the Mary Carter Greenway I > encounter an odd looking bird that I could not figure out. It was all brown > with fine streaks along the breast and belly but the bill was wrong for a > finch and it was too big. Then I noticed it was flapping around from branch > to branch frantically, and I noticed it was chasing a yellow warbler male and > constantly calling. I could not make sense of why this bird would be chasing > a warbler and calling like that. Finley both stopped on a Russian olive > branch and I was able to get a better view. I observed the warbler glean an > insect (likely a gnat) and take it lower down to the unknown bird and stick > it in the bird’s mouth. It finally came together then. This was a recently > fledged juvenile brown headed cowbird that the warbler believed to be its > offspring. It was certainly dwarfed by the cowbird. I have not seen this in > the wild before, I have one nature programs but that was it. Interesting > behavior to watch, not all that good for the warblers however. Hopefully > their population will not be to affected by this along the river. This was at > the mile marker 12, the dirt walking path goes through some woods that is a > favorite for warblers and other birds. Thought I would share this. > > Brian Johnson > > Englewood CO > > -- > 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 [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/cobirds/e6a087cd-2a5e-475a-ae68-035ce6e3d871%40googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- > 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 [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/cobirds/880480934A114201BE5F208CA72F45EC%40jimPC. > For more options, visit https://groups.google.com/d/optout. -- 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 [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/FD0BB150-DFE9-4321-897D-A4C0A1E6971D%40comcast.net. For more options, visit https://groups.google.com/d/optout.
