IBRC 11-B-10

Idaho Bird Records Committee Rarities Report Form

 

Species: Iceland Gull

 

Reporter: Jay Carlisle

Idaho Bird Observatory, Boise State University, 1910 University Ave., Boise, ID 83725; jaycarlisle@boisestate.edu

 

Other Observers: Heidi Ware, RL Rowland

 

Date Report Prepared: 1-16-10

 

Date Sighting Occurred:  12-24-09; from ~1210pm to ~225pm (also seen by other observers off & on thru 1-14-10)

 

Locality of Observation: Hidden Hollow landfill, Ada Co.

 

Habitat: garbage dump

 

Conditions: sunny, cold; I used Swarovski EL 10x42 binoculars and a Fujinon scope with 20-60x zoom

 

Did you take notes?  not at all

 

Did you consult a field guide or other reference work? after the observation

           

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

Sibley & National Geographic – as well as various websites; Howell & Dunn’s gull guide

 

Description:  An adult Iceland Gull in winter plumage.

 

When we arrived, RL Rowland spotted an adult gull with grayish wingtips that flew in and landed nearby. It looked big and with gray-tipped wings as it flew in so we first wondered about Glaucous-winged but the yellow eyes, smaller bill, rounded head shape, and eyes more forward on face suggested otherwise.  The longer we studied, the more we wondered about an adult Iceland (Kumlien's because of the gray, not white, primary tips) ... in particular, at one point after the gulls had been flushed & then settled again, the presumed Iceland was perched directly in front of the adult Glaucous 1st seen the day before (separate report) providing a brief comparison. In addition to being smaller, the bird had a longer primary projection, daintier bill, more rounded head, and less of a 'tertial stack' (basically, more attenuated body shape) than the Glaucous.

 

Behavior:  1st seen in flight over a gull roosting area; over the next 2 hours, alternately seen roosting, feeding, and/or flying back and forth

 

How and when did you positively identify the bird, and what clinched the identification for you?  The small, rounded head, relatively small bill, pink legs, yellow eyes, long primary projection, and somewhat deep belly. The key feature that got us thinking towards Iceland in the first place is that the primaries have gray shading.

 

How did you eliminate similar species, and what were they?  Possibilities include Thayer’s Gull (darker wingtips even on the palest adults, usually brownish eyes), Glaucous Gull (pure white wingtips, larger size, longer bill, usually less-rounded head, and shorter primary projection), and Glaucous-winged Gull (larger size, dark eye, more dark gray in wingtips).  Hybrid possibilities could include combinations of Herring, Glaucous, or Glaucous-winged but the small head and long primary projection argue against these possibilities.

 

Experience with this species (and similar species):  I have observed 10s of Iceland Gulls on the east coast (especially MA & CT), especially including adults and 1st winter birds, as well as individual birds in SD (1st-winter), WA (2nd-winter), and Idaho (March 2009 in Canyon Co.).  I have seen adult Glaucous Gulls in Alaska and 1st or 2nd winter birds in a number of states and on this day (separate report).  I have seen hundreds of Glaucous-winged Gulls (all ages) along the west coast (especially Washington), including a breeding-plumaged adult within an hour of this sighting at the same location (see separate report).  I have also observed large #s of adult Thayer’s (especially in winter in Oregon). 

 

Heidi has less gulling experience but has seen 12 gull species in Idaho in 2009 and she discovered the above-mentioned Glaucous Gull on the same day – which provided good comparison. 

 

General birding experience: extensive; 15+ years in US and Latin America

 

Were photo(s), video, and/or audio obtained by you? (If yes, please include or attach)    Yes – 7 pics of the presumed ‘Kumlien’s’ Iceland and one of a nearby adult Glaucous (for comparison)