Resource availability is a key factor driving marine bird movements and distributions, but direct information on prey availability is difficult to obtain at relevant scales. We present novel methods for describing multi-scale trophic associations, combining movement analyses of marine birds with estimates of forage fish surface aggregations from digital aerial survey data and species occupancy from bottom trawl survey data. We analyzed satellite telemetry data from northern gannetsMorus bassanus, red-throated loonsGavia stellata, and long-tailed ducksClangula hyemalisin the US Atlantic during the non-breeding period. Using discrete-time hidden Markov models to distinguish area-restricted (i.e. putative foraging) from transit movements, we examined how environmental factors influence movement, and how forage fish species distributions and surface aggregations influence habitat use by gannets and loons that have greater dietary reliance. Our results suggest that chlorophyllaconcentration significantly affected movement behavior across species, highlighting the importance of higher-productivity areas around estuaries during colder months when regional productivity is low. Though variable across species and seasons, spatial cross-correlation analysis revealed that herring species (Family Clupeidae), including Atlantic menhadenBrevoortia tyrannus, may be important resources; it also showed positive spatial correlations with forage fish aggregations. This suggests that prey patch dynamics and factors driving aggregation formation may be as important as species composition. However, spatial patterns were generally low (<0.3), suggesting a mismatch in spatiotemporal resolution, exemplifying the challenges in quantifying trophic relationships in marine systems. Disentangling predator-prey relationships is critical to understanding the mechanisms driving marine bird behavior in rapidly changing marine systems.
Gulka, J., et al. "Assessing individual movement, habitat use, and behavior of non-breeding marine birds in relation to prey availability in the US Atlantic." Marine Ecology - Progress Series, vol. 711, May. 2023. https://doi.org/10.3354/meps14316
Gulka, J., Berlin, AM, Friedland, KD, Gilbert, AT, Goetsch, C., Montevecchi, WA, Perry, M., Stenhouse, IJ, Williams, KA, & Adams, EM (2023). Assessing individual movement, habitat use, and behavior of non-breeding marine birds in relation to prey availability in the US Atlantic. Marine Ecology - Progress Series, 711. https://doi.org/10.3354/meps14316
Gulka, J., Berlin, AM, Friedland, KD, et al., "Assessing individual movement, habitat use, and behavior of non-breeding marine birds in relation to prey availability in the US Atlantic," Marine Ecology - Progress Series 711 (2023), https://doi.org/10.3354/meps14316
@article{osti_2424387,
author = {Gulka, J. and Berlin, AM and Friedland, KD and Gilbert, AT and Goetsch, C. and Montevecchi, WA and Perry, M. and Stenhouse, IJ and Williams, KA and Adams, EM},
title = {Assessing individual movement, habitat use, and behavior of non-breeding marine birds in relation to prey availability in the US Atlantic},
annote = {Resource availability is a key factor driving marine bird movements and distributions, but direct information on prey availability is difficult to obtain at relevant scales. We present novel methods for describing multi-scale trophic associations, combining movement analyses of marine birds with estimates of forage fish surface aggregations from digital aerial survey data and species occupancy from bottom trawl survey data. We analyzed satellite telemetry data from northern gannetsMorus bassanus, red-throated loonsGavia stellata, and long-tailed ducksClangula hyemalisin the US Atlantic during the non-breeding period. Using discrete-time hidden Markov models to distinguish area-restricted (i.e. putative foraging) from transit movements, we examined how environmental factors influence movement, and how forage fish species distributions and surface aggregations influence habitat use by gannets and loons that have greater dietary reliance. Our results suggest that chlorophyllaconcentration significantly affected movement behavior across species, highlighting the importance of higher-productivity areas around estuaries during colder months when regional productivity is low. Though variable across species and seasons, spatial cross-correlation analysis revealed that herring species (Family Clupeidae), including Atlantic menhadenBrevoortia tyrannus, may be important resources; it also showed positive spatial correlations with forage fish aggregations. This suggests that prey patch dynamics and factors driving aggregation formation may be as important as species composition. However, spatial patterns were generally low (},
doi = {10.3354/meps14316},
url = {https://www.osti.gov/biblio/2424387},
journal = {Marine Ecology - Progress Series},
issn = {ISSN 0171-8630},
volume = {711},
place = {United States},
publisher = {Inter-Research Science Publisher},
year = {2023},
month = {05}}