Changes in the Population Size of Yellow-legged Gull Larus michahellis at Essaouira and Mogador Island, West-central Morocco

A significant increase in the Yellow-legged Gull (Larus michahellis) population has been observed in the Essaouira–Mogador Island area of West-central Morocco, with an annual growth rate of 3.58% since 1985. The study, conducted in 2019 using point-transect sampling, estimated a population size of nearly 30,000 birds, with the highest density recorded on Mogador Island at 217.2 ± 28.3 birds/ha—markedly higher than previous records. The average reproductive rate was 1.04 chicks per pair annually, suggesting stable reproduction despite population growth. Researchers attribute this boom primarily to increased food availability from open landfill sites, though further studies are needed to fully understand the impact of food abundance on colony dynamics.

Bellout, S., Baamrane, M. A. A., Aamiri, A., & Aourir, M. (2021). Changes in the Population Size of Yellow-legged Gull Larus michahellis at Essaouira and Mogador Island, West-central Morocco. Marine Ornithology, 49(1). https://doi.org/10.5038/2074-1235.49.1.1405