Mexico’s Coronado Islands: Brown Boobies, cormorants, oystercatchers, and pinnipeds

2011 March 12
by David J. Ringer

After seeing Rhinoceros Auklets and Xantus’s Murrelets on the first half of Sunday’s San Diego Bird Festival pelagic trip, we reached Mexico’s Islas Cornado (Coronado Islands), four rocky islands off the coast of northern Baja California. The islands teem with bird life, mostly seabirds and shorebirds, though we did spot a Black Phoebe and a couple of House Finches. There’s lots to see, so sit back and enjoy this photo-heavy post. (The experience also inspired my column this month at 10,000 Birds, so check that out when you’re done: Meet Suliformes, one of the newest orders of birds.)

Brown Pelican, Pelecanus occidentalis

A Brown Pelican (Pelecanus occidentalis) being dramatic. The bright coloration is characteristic of the californicus subspecies.

Brown Booby colony

Brown Boobies

In the last 10 years, Brown Boobies (Sula leucogaster) have colonized Middle Rock in the Coronado Islands. This colony — the northernmost on North America’s Pacific Coast — has numbered in the low 30s for the past couple of years.

male Brown Booby

Graceful and beautiful, Brown Boobies are pantropical seabirds. The race here is brewsteri, and males like this one are easily identified by their frosty white heads.

Brown Boobies with chick

A pair tends a fuzzy white chick.

Brown Booby pair

Female (left) and male (right) flying together. Note female’s slightly larger size, brown head, and yellow facial skin.

Cormorants

Three species of cormorant frequent the islands.

Brandt's Cormorants, Phalacrocorax penicillatus

Brandt’s Cormorants (Phalacrocorax penicillatus) are the most abundant. Adults in high breeding plumage can be stunning — sapphire eyes, electric blue gular pouches set off by ivory-colored feathers, white filoplumes on the neck and back, and a blue-green gloss to their body plumage.

Pelagic Cormorants

A few Pelagic Cormorants (Phalacrocorax pelagicus) clung to nearly vertical slopes on Middle Rock. The distance makes detail difficult to see, but Pelagic Cormorants show small, slender heads and bills compared to the larger Brandt’s Cormorants (one at lower left).

Two Pelagic Cormorants, one of which has exposed the fluffy white tuft on its flank, and a Brandt’s Cormorant (far right).

Double-crested Cormorants

North Island held a few nesting Double-crested Cormorants (Phalacrocorax auritus). The backgrounds make head plume details difficult to distinguish in this shot, but if you look closely you can see the top bird’s white head plumes (typical of West Coast birds) and the lower bird’s black head plumes. These ear-like tufts give the species both its English and scientific names.

Oystercatchers

Black Oystercatcher, Haematopus bachmani

A striking Black Oystercatcher, Haematopus bachmani.

hybrid oystercatcher

And a confusing oystercatcher, which may be an American x Black hybrid. After intensive hunting greatly reduced oystercather populations, the two species have come back into contact along Baja California’s Pacific coast and — it’s believed — interbreed more now than they did historically while they reach a new equilibrium. This bird shows and extensive black bib with scalloped edges, but even pure Americans of the local race show some scalloping. There’s a detailed index for scoring oystercatchers, but most of the features aren’t visible in this image. Nevertheless, an interesting bird, and several trip leaders felt comfortable calling it a hybrid.

Pinnipeds

Harbor seals, Phoca vitulina

Harbor seals, Phoca vitulina

Northern elephant seal, Mirounga angustirostris

Northern elephant seal, Mirounga angustirostris, resting near a partly visible harbor seal (right).

California sea lions, Zalophus californianus

California sea lions (Zalophus californianus) piled up and sleeping under a rock.

Lagniappe

nesting Brown Pelicans

Most of my experience with Brown Pelicans is on the Gulf Coast, where they nest on marshy islands or in mangroves, so I was excited to see them nesting in a very different environment — rocky cliffs studded with prickly pear cacti.

Middle Island

Middle Island, one of the four Coronado Islands

Black Oystercatcher and California sea lion

Black Oystercatcher (left) and California sea lion (right)

Western Gull and Brandt's Cormorant

A sharp-looking adult Western Gull (Larus occidentalis) and a Brandt’s Cormorant.

Related posts:

  1. Breeding-plumaged Neotropic Cormorants
  2. How do cormorants take off from the water?
  3. Solomon Islands birds
  4. Brown Pelicans in Dallas County!
  5. Bird checklists for Melanesian Islands
2 Responses
  1. March 13, 2011

    You’ve got some great photos there!

  2. Lisa Berger permalink
    March 14, 2011

    Your first image of the Brown Pelican is so Escheresque. What stunning art!

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