Norm et al.: Dowitchers, like many/most species of shorebirds exhibit, somewhat, delayed plumage maturation. That is, the one-year olds usually/often don't achieve "full" alternate plumage (more on that below) in their first summer. In fact, many/most don't wind up breeding with many of those not going all the to the breeding grounds. Thus, late in spring migration for particular species, a sizable percentage of individuals are one-year olds and can look quite different from older birds. In dowitchers, they tend not to get much red underneath, mostly replacing random scapulars and wing coverts. They might appear smaller due to body-condition differences, as, again, many won't be going all the way to the breeding grounds, so don't require good fat loads to get them through the lean conditions upon arrival at such northern and cold locales.
Finally, even among adult shorebirds, many individuals never replace all of their basic-plumage upperparts in a given pre-alternate molt. More usually, the upperparts are a mix of dull basic plumage and dark-centered and bright alternate feathers. Enjoy, Tony Leukering Villas, NJ -----Original Message----- From: [email protected] To: [email protected] Sent: Wed, May 26, 2010 6:31 pm Subject: Re: [cobirds] WEVI in RMNP Hey Tony- you're the guy when it comes to molts, so I have a question for you. If you think it's of general interest, feel free to reply to Cobirds. Birding on the eastern plains a week or so ago I came upon a flock of long-billed dowitchers. At that point it had begun to rain and the wind picked up, so I didn't really have a (comfortable) opportunity to carefully observe the birds. However, it immediately became clear upon a quick inspection that there were two "groupings" of birds in the flock; of about twenty total birds, there were around seventeen that were "normal" looking ruddy red long-bills. With them there were three birds that were slightly smaller, and I assumed that these were short-bills based on size alone. As I mentioned, conditions were not ripe for careful examination. However, there was one other factor that caught my attention- the three smaller birds showed not only a difference in size, but they were a much plainer gray color than the bigger birds- they appeared to be in more what I would call a basic plumage. Do short-billeds perhaps molt later than long-bills? Or am I completely off base here? What prompted me to ask was your comment on Scott Roederer's vireo. Scott had sent me a picture shortly after my sighting of a pair of dowitchers up around Estes Park that showed a very similar contrast of both size and plumage. I had never heard that SB's would have a very noticeable plumage difference from LB's in spring migration, and the whole issue aroused my curiousity. Thanks! I'd be interested to hear your thoughts. Norm Lewis -----Original Message----- From: [email protected] To: [email protected]: Sent: Wed, May 26, 2010 2:47 pm Subject: [cobirds] WEVI in RMNP Hi all: As an addendum to Scott Roederer's post about the recent White-eyed Vireo at Rocky Mtn NP, I can tell you that one was banded by RMBO staff in either Moraine Park or Endovalley in spring/summer 1997. At least, I think that was the year. The record was eventually accepted by the CBRC. Tony Leukering Villas, NJ -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en. -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
