First full census in 45 years of a large colony of breeding penguins at False Round Point, King George Island

Abstract On 4 January 2025, we surveyed the breeding population of penguins at False Round Point (FRPT), King George Island, Antarctica. Historically, the colony of chinstrap penguins ( Pygoscelis antarcticus ) at FRPT was among the largest in the South Shetland Islands, but the most-recent full census, reporting 49,410 nests, occurred in 1980. Chinstrap penguin populations have declined precipitously since the early 1980s at other colonies in the northern Antarctic Peninsula and South Shetland Island region, driving a need for accurate estimates of penguin abundance to inform fishery management initiatives. Despite concerted efforts to broadly monitor chinstrap penguin populations, including the use of high-resolution satellite photography to census penguins on a circumpolar scale, information on the abundance of breeding penguins in many colonies has not been regularly updated for a variety of reasons, including remote and/or treacherous landings, time constraints for visitation, or cloud cover in remotely sensed images that preclude an assessment of colony size. To update the census for this large colony, we landed at FRPT and conducted an aerial survey of the entire colony using small unoccupied aerial systems. From the resulting orthomosaic image, we report a raw count of 19,886 occupied chinstrap penguin nests, representing a 59% decline in nest abundance in 45 years. We also counted 314 gentoo penguin ( P. papua ) nests and five individual king penguins ( Aptenodytes patagonicus ) during the survey; the presence of these species at False Round Point has not been previously reported.