Weathering a Dynamic Seascape: Influences of Wind and Rain on a Seabird's Year-Round Activity Budgets

Type Article
Date 2015-11
Language English
Author(s) Pistorius Pierre A.1, Hindell Mark A.2, Tremblay YannORCID3, Rishworth Gavin M.1
Affiliation(s) 1 : Nelson Mandela Metropolitan Univ, Percy FitzPatrick Inst, Dept Zool, DST NRF Ctr Excellence, ZA-6031 Summerstrand, South Africa.
2 : Univ Tasmania, Inst Marine & Antarctic Studies, Hobart, Tas 7001, Australia.
3 : Ctr Rech Halieut Mediterraneenne & Tropicale, Inst Rech Dev, UMR EME Exploited Marine Ecosyst 212, F-34203 Sete, France.
Source Plos One (1932-6203) (Public Library Science), 2015-11 , Vol. 10 , N. 11 , P. e0142623. (17p.)
DOI 10.1371/journal.pone.0142623
WOS© Times Cited 11
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.

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