IBRC 12-B-10

Idaho Bird Records Committee
Rarities Report Form

Species: Glaucous Gull

Reporter: Danette  Henderson

1202 N. 21st St., Bosie, ID  83702

(208)383-0421

danette444@gmail.com

Other Observers: Matthew Henderson, Jo Henderson, Iris Henderson

Date Report Prepared: 1-19-10

Date Sighting Occurred:  12-30-09 from 2:15-3:45pm.  Bird continued to be seen by other observers from through

Locality of Observation: Hidden Hollow Landfill, Ada Co.

Habitat: garbage dump

Conditions: mostly sunny, cold (34 degrees F), light wind (6mph). I used Swarovski EL 10x42 binoculars and a Swarovski 80 HD scope with 25-50x zoom.

Did you take notes?  No

Did you consult a field guide or other reference work? Yes

           

What guide(s) or reference(s) did you consult?

During the observation I used Sibley’s (copyright 2003) and National Geographic Birds of Western North America (copyright 2006).  During observation called Jay Carlisle to narrow down the species.  Once able to access my computer, viewed various online references. 

Sent photos to Jay Carlisle and Cliff Weisse for assistance with identification.

Description:  Second winter Glaucous Gull.

While scanning a group of primarily Ring-billed and California Gulls, I noticed a larger gull with all white primaries.  I thought it was an adult Glaucous Gull at first glance because we had seen an adult Glaucous approximately half an hour earlier on this visit and a week prior at this same location.  As I got the bird in the  scope, it turned showing it’s upperparts – they were not the pale gray of the adult Glaucous; they were light and mottled.  We began consulting guides and I telephoned Jay Carlisle for assistance.  Jo and Matthew Henderson were able to get several photos of the bird.  The bird let us view it for nearly an hour. 

Once we were home I was able to do side-by-side comparisons between this bird and online photos of Glaucous Gulls and Iceland Gulls (the only other gull I thought could be a possibility).  I also sent the photos to Jay Carlisle and Cliff Weisse for assistance, they both determined the bird to be a second-winter Glaucous Gull.  The size, pink legs, bill size (larger than Iceland), head shape (flat forehead) and length of wing projection (not as far past the tail as an Iceland), and “shorter” appearance in comparison with an Iceland Gull lead to presuming the species to be a second-winter Glaucous Gull.  The second-winter determination vs. a first-winter are attributed to the eye color (pale vs. dark) and the mottling on the upperparts. 

The bird has been consistently viewed at this location through yesterday (1/18/10).

Behavior:  First seen on the ground; only took flight once during our observation – in flight showed all white primary tips.

 

How and when did you positively identify the bird, and what clinched the identification for you?  

The size of the bird, larger head, bill shape and size, pink legs, relatively flat forehead, light eye.  Consultation with experienced gull observers.

How did you eliminate similar species, and what were they?

The only species I found to be a possibility was the Iceland Gull, as denoted above. 

If there are hybrid possibilities, I don’t not feel qualified to make those evaluations.

Experience with this species (and similar species):

I have very little experience with gull identification of any species.  The week before this sighting, and on this same day, I observed an adult Glaucous Gull.

General birding experience:

Limited experience, less than 2 years.

Were photo(s), video, and/or audio obtained by you? (If yes, please include or attach)   

Yes –  5 pictures of the presumed second-winter Glaucous Gull are attached.