title: Weathering a Dynamic Seascape: Influences of Wind and Rain on a Seabird's Year-Round Activity Budgets.
abstract: How animals respond to varying environmental conditions is fundamental to ecology and is a question that has gained impetus due to mounting evidence indicating negative effects of global change on biodiversity. Behavioural plasticity is one mechanism that enables individuals and species to deal with environmental changes, yet for many taxa information on behavioural parameters and their capacity to change are lacking or restricted to certain periods within the annual cycle. This is particularly true for seabirds where year-round behavioural information is intrinsically challenging to acquire due to their reliance on the marine environment where they are difficult to study. Using data from over 13,000 foraging trips throughout the annual cycle, acquired using new-generation automated VHF technology, we described sex-specific, year-round activity budgets in Cape gannets. Using these data we investigated the role of weather (wind and rain) on foraging activity and time allocated to nest attendance. Foraging activity was clearly influenced by wind speed, wind direction and rainfall during and outside the breeding season. Generally, strong wind conditions throughout the year resulted in relatively short foraging trips. Birds spent longer periods foraging when rainfall was moderate. Nest attendance, which was sex-specific outside of the breeding season, was also influenced by meteorological conditions. Large amounts of rainfall (> 2.5 mm per hour) and strong winds (> 13 m s-1) resulted in gannets spending shorter amounts of time at their nests. We discuss these findings in terms of life history strategies and implications for the use of seabirds as bio-indicators.
authors.affiliation: DST/NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology, Nelson Mandela Metropolitan University, Summerstrand 6031, South Africa.
authors.forename: Pierre A
authors.initials: PA
authors.lastname: Pistorius
authors.affiliation: Institute for Marine and Antarctic Studies, University of Tasmania, Tasmania 7001, Australia.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hindell
authors.affiliation: Institut de Recherche pour le Développement, UMR EME-212 Exploited Marine Ecosystems, Centre de Recherche Halieutique Méditerranéenne et Tropicale, Avenue Jean Monnet BP 171, 34203 Sète cedex, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Tremblay
authors.affiliation: DST/NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology, Nelson Mandela Metropolitan University, Summerstrand 6031, South Africa.
authors.forename: Gavin M
authors.initials: GM
authors.lastname: Rishworth
mesh_terms: D000818:Animals; D044822:Biodiversity; D001717:Birds / Q000502:physiology*; D004463:Ecology; D005247:Feeding Behavior; D005426:Flight, Animal / Q000502:physiology*; D009792:Oceans and Seas; D012621:Seasons; D014887:Weather; D014919:Wind