Time-lapse cameras reveal latitude and season influence breeding phenology durations in penguins

Abstract

Variation in the phenology of avian taxa has long been studied to understand how aspecies reacts to environmental changes over both space and time. Penguins(Sphenicidae) serve as an important example of how biotic and abiotic factors influence certain stages of seabird phenology because of their large ranges and the extreme, dynamic conditions present in their Southern Ocean habitats. Here, weexamined the phenology of gentoo (Pygoscelis papua) and chinstrap penguins(Pygoscelis antarctica) at 17 sites across the Scotia arc, including the first documentedmonitoring of phenology on the South Sandwich Islands, to determine which breeding phases are intrinsic, or rather vary across a species range and between years. Weused a novel method to measure seabird breeding phenology and egg and chick survival: time-lapse cameras. Contrary to the long-standing theory that these phases areconsistent between colonies, we found that latitude and season had a predominantinfluence on the length of the nest establishment, incubation, and guard durations.We observe a trend toward longer incubation times occurring farther south, whereambient temperatures are colder, which may indicate that exposure to cold slowsembryo growth. Across species, in colonies located farther south, parents abandoned nests later when eggs were lost or chicks died and the latest record of eggs orchicks in the nest occurred earlier during the breeding period. The variation in bothspace and time observed in penguin phenology provides evidence that the durationof phases within the annual cycle of birds is not fundamental, or genetic, as previously understood. Additionally, the recorded phenology dates should inform fieldresearchers on the best timing to count colonies at the peak of breeding, which ispoorly understood.