The eye that guards the rock: does it shape the world? nest site attendance patterns in a colonially breeding pelagic seabird

Understanding how animals use and value their breeding territories is important to interpreting the ecological and social pressures that shape reproductive strategies, particularly in species breeding in dense colonies and highly seasonal environments. In colonially nesting seabirds, where terrestrial space is often considered a low-value resource, patterns of territory use outside periods of direct parental care remain poorly understood. Drawing on six years of video monitoring in a well-established colony in Hornsund, Spitsbergen, we quantified territory attendance (non-parental nest-site attendance) in males and females of the little auk (Alle alle) – a small Arctic seabird, across the entire breeding season and compared successful breeders with pairs that experienced hatching failure. We found significant sex differences in the non-parental nest-site attendance, with males spending more time at the nest than females, particularly during mating, early incubation, and late chick-rearing stages. Failed breeders, spending more time on the nest spot than successful breeders, remained in the colony throughout the chick-rearing stage with no detectable difference between males and females. In the context of the ecology of the little auk, our findings indicate that non-parental nest-site attendance in the species reflects a complex interplay of parental investment, social dynamics, and long-term spatial attachment. Our results highlight that even in species with minimal territorial defensibility, territory use extends beyond periods of active care and should be considered when interpreting the behavioural ecology of colonial seabirds. Territory use outside periods of direct parental care is rarely examined in colonial seabirds, yet it can reveal how ecological and social pressures shape reproductive strategies. By analysing six years of nest-site monitoring in little auks, we show that males and females differ markedly in how they use this breeding space across the season. Males allocate more time at the nest territory during mating, early incubation, and fledging than females. Failed breeders remain in the colony despite having no possibility of renesting, with no sex differences. These patterns demonstrate that nest sites hold intrinsic value beyond immediate reproduction, reflecting a combination of parental roles, social dynamics, and strong site fidelity. Our findings highlight overlooked dimensions of territory use in colonial seabirds.