ML154793231
Iceland Gull (Thayer's x Iceland) Larus glaucoides thayeri x glaucoides/kumlieni
Contributor
Date
Location
- Age
- Not specified
- Sex
- Not specified
Observation details
Possible hybrid Thayer's Gull X Kumlien's Gull (Larus thayeri X L. [glaucoides] kumlieni) at Canal Park, Duluth, Minnesota, 25 November 2012. The bill of hybrid Herring Gull X Glaucous Gull ("Nelson's" Gull, an example of which was photographed here by Karl Bardon in late Nov) is usually larger and heavier-looking, and its mantle shade is usually lighter than that of American Herring Gull. Size comparisons with multiple Herring Gulls in these images, some of which are in the foreground and some of which are in the background, suggest that this bird is too large, too stocky, and displays the wrong wing-tip pattern for "pure" kumlieni. Eye color can vary within species (e.g., a small percentage of adult thayeri show yellow irides), and may not be fully expressed in hybrid pairings; also, thayeri shows black (not gray) in its wing-tips. Hybrid characters are not necessarily intermediate between the two parent species and backcrosses complicate matters. Our best guess is hybrid thayeri X kumlieni, but Herring, Glaucous-winged, or Glaucous may also be involved. Can Herring Gull X Glaucous-winged Gull be ruled out? My thanks to Karl J. Bardon for thought-provoking analysis and discussion of these images. Additional images and discussion at http://www.flickr.com/photos/cochon/sets/72157632558244448/
Technical information
- Original file size
- 4.21 MB