Kathy Molina,

Kathy Molina,

A weeklong electronic journal.
June 25 1998 3:30 AM

Kathy Molina,

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       The morning observation periods (from about 5:30 to 8:30) are definitely my favorites, although bird activity levels are somewhat decreased. With the rising sun this morning, the winds diminished, and I could detect the faint scent of spent mesquite and paloverde blossoms. Yes, some of the natural desert flora still persists here. The dry rattlings of marsh wrens and the scratchy wailings of yellow-headed blackbirds emanate from the cattail pond behind me. This morning the alkaline landscape didn't seem nearly as disagreeable as it had the previous day; in fact, it was even comforting.
       Today, during my scans of these tiny nesting islets, I found a fair bit of diversity. At least three avocet nests are scattered among the tern and skimmer nests; two pairs of stilts have wedged their nests along the rocky shoreline, along with a pair of killdeer. Also during my scans, I noted at least five birds with color-band combinations that I had not detected since banding them years before. Interestingly, most of these were 2-year-olds. I can't be certain yet that these birds are nesting, but in terns, many young first-time breeders do so later in the season. A new wave of nest initiation seems to be occurring on two of the islets. Again, because not all are color marked, I cannot determine whether these are new breeders, birds that are dispersing from other nesting areas, or birds whose initial attempts here were interrupted by a roosting flock of pelicans late last month.
       The previously mown refuge fields of sudan grass were flooded up today, and this may explain the abundance of crickets that were fed to chicks this afternoon. This will be a good food source, especially for the smaller chicks. While most terns feed primarily on fish, gull-billeds are unusual in that they commonly prey on insects.
       During the afternoon session (when it was 104 degrees), my attention to the activities of Nests R50 and R139 was diverted momentarily. I watched, in the background, two gulls tug apart a small, probably abandoned tern chick. Unlike many nesting colonies, we are, or rather were, relatively predator-free here during the nesting season. More of the overwintering gulls seem to be staying on through summer, and this is beginning to figure significantly in our chick mortality rates. But back to behavior study. Nest attendance at R50 and R139 continues uninterrupted. Relatively few unattached birds now rest on the islet, so there are few territorial squabbles. There seems to be some variation in the way in which these two pairs approach incubation duties. The R50 pair seems to relieve each other much more frequently than do the mates at R139. The off-duty parent at R50 often remains on the territory, preening or simply resting. These differences may have important consequences for the successful hatching and raising of offspring. We shall have to wait and see.

Kathy Molina is a research biologist studying the breeding ecology of water birds at the Salton Sea, a saline lake in the Colorado Desert of southeastern California. She is currently completing an M.S. degree at California State University, Northridge.