Iceland or Glaucous Gull?

Gulls Can Be Difficult to Distinguish

Iceland Gull First Winter

Some, indeed many, species of gulls are difficult to identify.  Given that gulls take 2 or 3 years to reach adulthood and that they have 5 or more different plumages along the way, no wonder identification is difficult!  

This post will attempt to clarify the difference between the 1st winter Iceland and Glaucous Gulls.  This is a problem often faced by New Brunswick birders because these gulls are often found here in winter.  Immature Glaucous and Iceland Gulls are much more common here than adults.  Non-breeding Iceland Gulls (Larus glaucoides) are found here mainly in winter.  They winter along water from the Great Lakes to Labrador, around the coast of Newfoundland, the Gulf of St. Lawrence and along the Atlantic seaboard as far south as North Carolina.  They breed in summer along the western coast of Greenland and the southern part of Baffin Island.  

The Glaucous Gull (Larus hyperboreus) is more geographically widespread in North America.  Non-breeders spend their summers (and some year-round) on both coasts of Canada, in the west along the entire coast of British Columbia, Yukon and Alaska and in the east from the Great Lakes to Labrador, the Gulf of St. Lawrence and down the eastern seaboard to North Carolina.  Non-breeders also are found in waters from Northern Labrador to Greenland north to Baffin Island.  Adult Glaucous Gulls spend summers on breeding grounds along the coasts of northern Labrador, Greenland, Baffin Island and most Arctic Islands northward.  They also breed along the north coast of Yukon, Nunavut, Northwest Territories and Alaska.

Glaucous Gull First Winter

Note the two species shown in the photos above.  As can be seen, they are very similar.  So how do we tell them apart?  Firstly, the Glaucous Gull is larger than the Iceland Gull (69 cm/27 inches vs. 56 cm/22 inches).  But this is not much help if we see just one bird and have nothing for comparison.  Following are some other features to help identify these species.

Iceland Gull First Winter

Both Iceland and Glaucous Gulls are white-winged gulls.  White-winged gulls do not have black wingtips like our common gulls, Herring Gulls, for example.  Their wingtips vary from white to brownish gray.  See the photos above.  The bill of the Iceland Gull is shorter and more slender than the bill of the Glaucous Gull.  On both species when at rest, the wing tips extend beyond the tail feathers.  The 'wing projection' is longer in the Iceland Gull than in the Glaucous Gull.  The juvenile Iceland Gull is pale brown to creamy overall with variations in the amount of white mottling.  The comparable Glaucous Gull is much whiter in colour.  Both species have a dark eye at this stage.  The Glaucous Gull at this age shows a bi-coloured bill with pink at the base and black at the tip, and showing a sharp demarcation between the two colours.  The juvenile Iceland Gull has a black bill but it gradually transforms to a bi-coloured bill in the next year, with a not-so-clear demarcation between the pink and black. Both species have pink legs.  The wingtips in the Glaucous Gull are often white or whitish whereas the Iceland Gull wingtips at the stage are often brownish to grayish.  

Iceland Gull First Winter

It is always interesting to see these gulls in winter.  In the spring they leave and spend their summers further north.  'Our' Iceland Gulls will move to the coast of Newfoundland and northern Labrador and our Glaucous Gulls will probably fly to the north coast of Labrador, Greenland or Baffin Island.  

Glaucous Gull (front); Iceland Gull (behind)

The photo above shows clearly the difference in plumage colour and bill shape.  Iceland and Glaucous Gulls are always a challenge this time of year.  I admire these interesting species that are adapted to cold temperatures and thus can reap the benefits of feeding off the cold northern Atlantic shores.