The Western Gull (Larus occidentalis) is the”typical” large, white-headed gull of the west coast of the US. Seen at most beaches, but rarely inland (except at the Salton Sea), this is more of an obligate “sea” gull than other gulls. They breed on offshore islands during the summer, and the Farallones constitute an important breeding location for them. They are the most obvious island resident due to their numbers and their character. Here, a brilliant quote from one of California’s earliest naturalists – William Leon Dawson.
Much that is good and all that is evil has gathered itself up into the Western Gull. He is rather the handsomest of the blue-mantled Laridae, for the depth of color in the mantle, in sharp contrast with the snowy plumage of back and breast, gives him an appearance of sturdiness and quality which is not easily dispelled by subsequent knowledge of the black heart within. As a scavanger, the Western Gull is impeccable. Wielding the besom of hunger, he and his kind sweep the beaches clean and purge the water-front of all pollution. But a scavanger is not necessarily a good citizen. Call him a ghoul, rather, for the Western Gull is cruel of beak and bottomless of maw. Pity, with him, is a thing unknown; and when one of their own comrades dies, these feathered jackals fall upon him without compunction, a veritable Leichnamveranderungsgebrauchsgesellschaft. If he thus mistreats his own kind, be assured that this gull asks only two questions of any other living thing: First, ‘Am I hungry?’ (Ans., ‘Yes,’) Second, ‘Can I get away with it?’ (Ans., ‘I’ll try.’)
[…]Nothing in the life of the Farallons [sic] is more striking than the rapacity of the gulls and their determination to profit by any excitement which will frighten the peasantry.
“Much that is good and all that is evil…” William Leon Dawson understood the nature of the Western Gull through and through. From my arrival in March, to the day before the first nest had eggs, I failed to understand the “…all that is evil…” part of the quote. After all, while the overarching presence of the WEGUs looked like inspiration for Hitchcock’s The Birds, they were easy to get along with. However, as soon as the birds had laid their eggs, their character changed – hormones coursing through the birds’ brains and bodies changed them into screaming harpies who wanted humans nowhere near their nest and would stop at nothing to deter them. In many ways, it was quite admirable behavior, the level to which they directed their aggression to protect their nest and offspring. The level ramped up even more once the eggs hatched and chicks were wandering their parents’ territories. Walking outside became like going through some gull hazing gauntlet. While there had never been a moment of silence from gull calls and screams, once chicks hatched, the volume seemed to increase ten-fold. It became impossible to hold a conversation outside with anyone without using your “Farallon Voice”. And any time one of us entered a gull’s specific territory (which was pretty much everywhere on the island), we were treated to that pair’s aggression – swooping, a special scream, a bill-smack on the head (hardhats became necesarry to wear when outside for about a two-month period) and, if you were especially loathed, a particularly well-aimed stream of hot, stinky gull shit.
The Western Gulls begin reclaiming their territories from the previous breeding season around March. They show up at their old territory and wait for their mate to show up to reform pair bonds and breed. Around late March there are mating gulls everywhere – and we all got really familiar with their low, throaty copulation call. Hence, one of the earliest seabird studies that commences on the island is the WEGU productivity study – each intern is assigned one of 4-5 study plots (which have been plots for upwards of a couple decades) and every day we spend a few hours trying to ID banded gulls present on the plot. I enjoyed it as it took some focus and stealth to move around the bird (or, if you’re really skilled, manipulate its behavior so that it gives you a full turn) to get the whole band number. Always a challenge when the bird is turning with you to keep you in front of it, or running away from you, moving its legs too fast to get a reading, or worse, taking off to disappear into the great blue beyond. When it was windy, maybe blowing over 10-15 knots, it was really hard to keep your binoculars steady enough to get a reading, and the gulls tended to hunker down so their legs weren’t visible anyways.
It took some practice but eventually we all got the hang of it, and were able to account for most of the birds that were supposed to be on our plot. Some birds were absent, but that wasn’t a big deal as sometimes the WEGU’s take a year off from breeding/parenting, or maybe they had died in which case they wouldn’t return the following year either. IIRC, if a WEGU wasn’t present for the third season, it would be dropped from the study. A few of the older birds have been returning for 30 years – this is the upper limit of the known WEGU life span so if these individuals keep coming back to the Farallones to breed then we will be getting valuable data indeed!
Band reading was a daily activity until around the time the first eggs were to appear early May, at which point we would switch to nest monitoring. My plot (K-plot) was historically the lowest-productivity plot, perhaps due to its more exposed nature – although it was by far the most scenic plot. Because of this exposure, it could have been lower quality nesting habitat which the lowliest gulls were relegated to. Or maybe none of them were experienced parents, or weren’t too into the whole parenting thing anyways. Of course, we had no measure for this. On any island with complex habitat, there are micro-habitats that have varying factors that influence breeding biology. Varying productivity applied across the different murre and corm colonies as well.
When I returned to the island in June, it was like a whole new island, denuded of plants but with chicks everywhere and WEGU adults screaming and dive-bombing every single human. I had been assigned a new plot – H-plot West, one of the busiest and most productive, and it was a bit of a hassle to relearn the nests in a much more condensed version. Also, the bands used for the gull chicks (the vast majority of them had been banded before I returned, although I got to band a couple) were faulty and the numbers printed on them were really hard to read.
The WEGU study at this point had transitioned to following chick fates – keeping track of who survived to fledge, who died, when, and how. Causes of death include being eaten by another gull if it was young/small enough (this happened especially to the chicks of late breeders), starvation, PIH (pecked in head, by another gull), botulism, or unknown (chick disappears pre-fledge age). By the end of August, all the chicks had fledged, and the WEGU study was concluded. Where for much of the summer, the days and nights were dominated with the unceasing screaming and squawking of hormonal WEGUs, it became eerily silent…