Brown Booby
Princeton Harbor, San Mateo County, California
2 January 2003
Joseph Morlan

Photos © 2 January 2003 by Joseph Morlan. All rights reserved.
This morning I received a phone call from Ron Thorn advising me that he had just found a Brown Booby at Princeton Harbor, Half Moon Bay. After making a few phone calls, I decided to drive down and have a look. When I arrived, I met Ron Thorn and Gary Deghi who were viewing the bird on the rock jetty directly south of the end of the main commercial pier in the harbor. Soon Dan Singer arrived and the bird continued to cooperate. The bird spent most of its time perched on the rocks preening. Eventually it seemed a bit more active when suddenly it flew out over the harbor and out to sea.

At this time Robbie Fischer, Bess Nericcio and John Luther arrived and we had to share the bad news. Dan left a message on the Northern California Birdbox stating that the bird had left. However, after about a half hour, the bird reappeared on top of the same jetty. None of us had seen it fly in. I called back to Bess who was just leaving and all had excellent views of the bird. Dan left a new Birdbox message stating that the bird had returned. Soon many interested birders arrived (I recognized Adam Winer, Jeff Wall, Sandy Koonce, Kris Olson, Vivek Tiwari, and Kathy Robertson) and all were afforded good scope views. Although the bird was fairly distant, I attempted digital photos. You can see the results here. Adam Winer also took some interesting video of the bird and has posted some captures here (you may have to login to Yahoo to access Adam's images).

The following description is based on notes while viewing the bird:

An obvious booby with long cone-shaped bill and long pointed tail. It was larger than adjacent Western Gull, but smaller than nearby Double-crested Cormorant.

The bird was entirely dark brown above contrasting strongly with a mottled light-brown coloration below. The dark brown included the entire head, neck and breast where it was sharply demarcated from the paler belly. In the middle of the lower breast, just below the dark demarcation, the underparts were whiter, lacking the dull brownish mottling visible on the rest of the underparts.

The bill was mostly olive-horn in color, sometimes appearing slightly greenish, except at the base where the bill showed a yellow-orange tinge, especially near the gape. No nostril was visible. The dark eye, seemed to have a dark greenish orbital ring with some dusky coloration extending forward of the eye onto the bill forming a slight dark wedge in front of each eye.

The legs appeared yellowish, but when the bird scratched, the webs of its toes appeared pinkish. All four toes could be seen to be webbed forming three webs on each foot.

The wing coverts were solid brown with no pale mottling at all. The wing linings appeared white out to the middle forming a point about half-way out the underwing. I looked for a dark stripe within the white area and did not see one. The outer half of the underwing and the frame around the white wing-linings, was dark brown.

The central tail-feathers appeared very long and pointed. Ron Thorn mentioned that the outer rectrices were blunter, but I was unable to see that in the views I had.

In flight the wings were bowed downward somewhat and appeared distinctly pointed. The bird flew low with long glides interspersed with slow flaps, recalling the flight style of an albatross.

This is the fourth Brown Booby I have seen in California. My prior sightings have been at the Salton Sea, Imperial County; the Farallon Islands, San Francisco County; and Point Reyes, Marin County.

Although there are at least three previous mid-winter records for Southern California, this appears to be the first mid-winter record for Northern California and is the first record for San Mateo County.

I believe this bird is best aged as a "subadult."


Click here for a short video clip of the bird taken 4 January 03 by Leslie Lieurance