The First GPS Observation of a Western Gull (Larus occidentalis) Riding in a Long-Haul Garbage Transfer Truck

Publication Date

5-29-2025

Document Type

Article

Publication Title

Waterbirds

Volume

48

Issue

1

DOI

10.1675/063.048.0101

Abstract

Gulls have a flexible diet allowing them to forage both at-sea and on land with prior research showing Western Gulls (Larus occidentalis) forage more on land when oceanic prey resources are low. Western Gulls have been GPS-tracked during the breeding season at Southeast Farallon Island off the U.S. West Coast from 2013 to the present. Foraging trips to land tend to be longer than at-sea trips, and while on land, gulls can visit a variety of locations in search of anthropogenic food sources. Here, we provide the first observation of a female Western Gull riding in a long-haul garbage transfer truck (18-wheeler) from a waste transfer station in San Francisco to an outdoor compost facility in the Central Valley, California. This behavior occurred twice, on 21 and 23 May 2018, and the gull flew back to its colony on the Farallon Islands after getting out of the truck each time. These two foraging trips were an average ~14 to 18 hrs longer, ~95 to 130 km farther from the colony, and the total distance traveled was ~95 to 160 km more than this individual's other at-sea and land-based trips during the week-long tracking period. While this behavior has not been widely observed and the bird's intentions are difficult to establish, foraging at this transfer station appears to provide a predictable food source, and therefore, this behavior could become more common as birds respond to changing environments.

Keywords

biologging, foraging, landfills, tracking, Western Gull

Department

Biological Sciences

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