[Birdnet] Re: [Birdtalk] Scaup quiz

[JEFF LANGFORD]

Ryan, I'll take a shot at this one. 
When I'm in town I bird virtually every weekend, frequently at Farmington Bay and Antelope Island, and occasionally Bear River, but I have observed greater scaup on only six different occasions since I took up birding in 2004. All but one of the observations was recorded in the past ten months. Part of the reason might be that until recently, I wasn't confident or interested enough to tackle this difficult ID and assumed virtually all scaups that visit this area are lesser. I birded Farmington Bay last Sunday and reported seeing both lesser and greater species. I relied primarily on head shape and bill pattern to make my determination. In addition to my trusty Sibley's, I have found Bill Thompson's excellent guide "Identify Yourself" which concerns itself with "The fifty Most Common Birding Identification Challenges" to be useful. Scaups and the similarly plumed ring-billed duck are discussed at length, but head shape and bill pattern are indicated as the primary field mark for identification. Thompson also writes that "the challenge depends in large part on where you are. If you are inland, the trick is to find the one or tow greater scaup in the flock of lessers. If you are along the coast, the situation is frequently reversed. I is usually safe to assume that inland flocks are almost all lessers." I queried the eBird database for Utah and it supports this generalization, but also shows reports increased during spring and fall migration. My personal observations also reflect this trend. With this backdrop here's my two-cents:

Photo 1: appears to be GREATER with rounded head. Whitish body lacks heavier, coarser barring of LESSER.

Photo2: possible peaked crown indicates LESSER? 

Photo3: (from left to right) #1&#2 difficult to ID. #3; GREATER. #4; LESSER. Based on comparing head profiles. Also, #3 appears to have whitish body which #4 lacks, but this could be due to the light/angle of photo.

Jay

  ----- Original Message ----- 
  From: Ryan O'Donnell<mailto:ryan at biology.usu.edu> 
  To: birdtalk at utahbirds.org<mailto:birdtalk at utahbirds.org> ; topofutah at utahbirds.org<mailto:topofutah at utahbirds.org> 
  Sent: Tuesday, March 25, 2008 1:40 PM
  Subject: [Birdtalk] Scaup quiz


  Following Buck's post on Saturday I went to the ponds west of the Logan
  Landfill in search of Greater Scaup.  I am still struggling to identify
  these in the field, but I felt like there was at least one and probably
  more that were Greaters.  When I returned with a group of other birders
  on Sunday morning we were unable to find any Greaters.  I took a bunch
  of photos on Saturday night and I wanted to solicit opinions on the
  three shots I thought looked most like Greaters (these may or may not be
  the same bird).  I've based my ID primarily on the height and length of
  the bill, the width of the bill, the size of the nail on the tip, the
  width of the head at the "jowels", and partly on the shape of the head
  in profile.  The pure white flanks was a minor corroborating point.
  Here are links to the photos:
   
  http://i110.photobucket.com/albums/n105/Tsirtalis/Scaup1.jpg<http://i110.photobucket.com/albums/n105/Tsirtalis/Scaup1.jpg>
  http://i110.photobucket.com/albums/n105/Tsirtalis/Scaup2.jpg<http://i110.photobucket.com/albums/n105/Tsirtalis/Scaup2.jpg>
  http://i110.photobucket.com/albums/n105/Tsirtalis/Scaup3.jpg<http://i110.photobucket.com/albums/n105/Tsirtalis/Scaup3.jpg>
   
  Thanks for your help,
  Ryan
   
  Ryan P. O'Donnell
  Department of Biology and the Ecology Center
  Utah State University
  5305 Old Main Hill
  Logan, UT 84322-5305
   
  http://200birds.blogspot.com<http://200birds.blogspot.com/>

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