title: Foraging behavior links climate variability and reproduction in North Pacific albatrosses.
abstract: BACKGROUND
  Climate-driven environmental change in the North Pacific has been well documented, with marked effects on the habitat and foraging behavior of marine predators. However, the mechanistic linkages connecting climate-driven changes in behavior to predator populations are not well understood. We evaluated the effects of climate-driven environmental variability on the reproductive success and foraging behavior of Laysan and Black-footed albatrosses breeding in the Northwest Hawaiian Islands during both brooding and incubating periods. We assessed foraging trip metrics and reproductive success using data collected from 2002-2012 and 1981-2012, respectively, relative to variability in the location of the Transition Zone Chlorophyll Front (TZCF, an important foraging region for albatrosses), sea surface temperature (SST), Multivariate ENSO Index (MEI), and the North Pacific Gyre Oscillation index (NPGO).
  
  
  RESULTS
  Foraging behavior for both species was influenced by climatic and oceanographic factors. While brooding chicks, both species traveled farther during La Niña conditions, when NPGO was high and when the TZCF was farther north (farther from the breeding site). Models showed that reproductive success for both species showed similar trends, correlating negatively with conditions observed during La Niña events (low MEI, high SST, high NPGO, increased distance to TZCF), but models for Laysan albatrosses explained a higher proportion of the variation. Spatial correlations of Laysan albatross reproductive success and SST anomalies highlighted strong negative correlations (>95 %) between habitat use and SST. Higher trip distance and/or duration during brooding were associated with decreased reproductive success.
  
  
  CONCLUSIONS
  Our findings suggest that during adverse conditions (La Niña conditions, high NPGO, northward displacement of the TZCF), both Laysan and Black-footed albatrosses took longer foraging trips and/or traveled farther during brooding, likely resulting in a lower reproductive success due to increased energetic costs. Our results link climate variability with both albatross behavior and reproductive success, information that is critical for predicting how albatross populations will respond to future climate change.
authors.affiliation: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11790 USA.
authors.forename: Lesley H
authors.initials: LH
authors.lastname: Thorne
authors.affiliation: Environmental Research Division, Southwest Fisheries Science Center, NOAA Fisheries, 99 Pacific St., Suite 255A, Monterey, CA 93940 USA ; Cooperative Institute for Marine Ecosystems and Climate, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 USA.
authors.forename: Elliott L
authors.initials: EL
authors.lastname: Hazen
authors.affiliation: Environmental Research Division, Southwest Fisheries Science Center, NOAA Fisheries, 99 Pacific St., Suite 255A, Monterey, CA 93940 USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Bograd
authors.affiliation: Environmental Research Division, Southwest Fisheries Science Center, NOAA Fisheries, 99 Pacific St., Suite 255A, Monterey, CA 93940 USA ; Cooperative Institute for Marine Ecosystems and Climate, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Foley
authors.affiliation: Department of Ocean Sciences, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 USA.
authors.forename: Melinda G
authors.initials: MG
authors.lastname: Conners
authors.affiliation: Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, OR 97331-3803 USA ; Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 USA.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Kappes
authors.affiliation: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11790 USA.
authors.forename: Hyemi M
authors.initials: HM
authors.lastname: Kim
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Costa
authors.affiliation: Institut de Recherche pour le Développement (IRD), Research Unit Marine Biodiversity, Exploitation and Conservation UMR248 MARBEC, Avenue Jean Monnet, CS 30171 - 34203 Sète Cedex, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Tremblay
authors.affiliation: Department of Biological Sciences, San José State University, One Washington Square, San Jose, CA 95192 USA ; Institute of Marine Sciences, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Shaffer
keywords: Albatross; Climate; Environmental variability; Movement; Reproductive success