Colonial breeding provides benefits such as reduced predation risk, but also entails costs due to the enhanced levels of competition. In particular, it may require a significant amount of time and energy to establish a territory at the onset of reproduction, which in turn can impose carry-over effects on subsequent reproductive investments. Here we made use of GPS tracking devices to test how a colonial breeder, the lesser black-backed gull (Larus fuscus), balances its time investment between territorial and foraging activities throughout the pre-laying period, and investigated possible fitness consequences. As hypothesized, individuals that spent more time in their territories reduced their foraging time, foraged closer to the colony, and spent less time commuting during foraging trips. Although males initially invested more time in establishing a territory, both sexes gradually spent more time in their territory as the onset of egg laying, an energetically demanding period, approached. Furthermore, males that exhibited a higher territory attendance alleviated the females’ time constraints for foraging and their partners laid larger eggs. Our results highlight the importance of quantifying carry-over effects related to time budgets during the (often understudied) pre-laying period, to better comprehend fitness consequences of colonial breeding. |
