Countless California Gulls Hide Heermann's Gulls

California Gulls (Larus californicus) at Wickaninnish Beach
A small section of the large flock of California Gulls (Larus californicus) at Wickaninnish Beach, Pacific Rim National Park Reserve.

It’s hard to describe the number of California Gulls (Larus californicus) that have descended on the beaches in Pacific Rim National Park Reserve on Vancouver Island since last week as the numbers continue to build. Fall migrants are arriving from breeding grounds in Saskatchewan, Alberta and the interior of BC make their way to the West Coast in mid August before continuing their migration south to California and Mexico. It’s an interesting migration pattern as the birds must fly over the Rocky Mountains before making following the coast southward. They’ll be here for another couple of weeks before beginning to depart in mid September.
California Gulls (Larus californicus) at Florencia Bay
More California Gulls (Larus californicus) at Florencia Bay in Pacific Rim National Park Reserve.

California Gulls (Larus californicus)
And even more California Gulls (Larus californicus) - note the yellowish or gray/green legs, and black-tipped wings.

Adult California Gulls are fairly easy to identify. They are a smaller gull (when compared to the more common Glaucous-winged Gull) and have black wingtips and yellowish or greenish-gray legs. In comparison with the somewhat similar looking Mew Gull (which also has yellow legs and black wingtips), the bill is more robust with a red and black spot in comparison to the Mew Gull’s thinner, “spot-less” bill.
California Gulls (Larus californicus)
California Gulls (Larus californicus)


I usually find juvenile gulls a challenge but in this case, most of the juvenile birds were also California Gulls so it wasn’t too difficult to identify them correctly. In a less homogeneous flock I don’t think I’d be as confident!

Juvenile California Gull (Larus californicus)
Juvenile California Gull (Larus californicus)

Heermann's Gulls (Larus heermanni)
A pair of Heermann's Gulls (Larus heermanni) in a large flock of California Gulls at Wickaninnish Beach on Vancouver Island, BC.

With such large flocks of California Gulls it pays to spend a little time sorting through the birds to look for other species. This week I was able to find a half dozen Heermann’s Gulls (Larus heermanni) in the flock. With their sooty gray bodies, black legs and red bills they look quite different from the California Gulls. All of the Heermann’s mixed in with the flock of California Gulls appear to be juveniles.
Heermann's Gull (Larus heermanni)
A juvenile Heermann's Gull (Larus heermanni).

Interestingly, the Heermann’s Gull has a different migration pattern, nesting in western Mexico in the early spring and then moving north along the west coast. Heermann’s Gulls can be seen fairly regularly in Victoria, British Columbia in the fall. Check out 10,000 Birds article on Heermann’s Gulls for a good overview of the species and excellent photographs of the adult birds.

I’m enjoying watching these large flocks of gulls along the beaches and at the mouths of streams and creeks in Pacific Rim National Park Reserve. They’ll only be here for several more weeks so while they’re here I’m going to continue searching through the flocks for more unusual gulls. With this number of birds on the beaches, something interesting is bound to turn up!

4 comments

  1. I think the most interesting part of the California Gull migration is that they didn’t used to do this…the big concentrations of Californias at Pacific Rim is a recent phenomona…

  2. I found a rather dated paper discussing banded California gulls from Saskatchewan showing up in the Lower Mainland, and in particular the Burns Bog dump, but now that I think about it it didn’t mention the west coast specifically. Thanks for the comment Dave!

  3. Pingback: Dave Ingram's Natural History Blog :: Single Sanderling Lingering

  4. Pingback: California Gulls on Vancouver Island in July | What Bird is This?

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