Integrating behavior and physiology supports Storer-Ashmole’s halo in a central place forager

• Published in: Marine biology 2024-11, Vol.171 (11), p.224, Article 224
• Main Authors: Lazarus, Thomas, Grant Gilchrist, H., Sorenson, Graham, Love, Oliver P., Janssen, Mike, White, Travis, Elliott, Kyle H.
• Format: Article
• Language: English
• Subjects: Aquatic birds; Biomarkers; Biomedical and Life Sciences; Chicks; Constraints; Costs; Depletion; Distance; Food chains; Forage; Foraging; Foraging behavior; Freshwater & Marine Ecology; Hypotheses; Incubation; Incubation period; Individual rearing; Life Sciences; Lipids; Marine & Freshwater Sciences; Marine biology; Metabolites; Microbiology; Nesting; Nutrient deficiency; Oceanography; Original Paper; Physiology; Plasma; Predation; Prey; Seabirds; Success; Swimming; Swimming behavior; Transit time; Triglycerides; Zoology
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-024-04547-7

Central place foraging may lead to local prey depletion as foragers select nearby prey (“Storer-Ashmole’s halo”), causing individuals to forage progressively farther from the central place. We tested this idea by coupling GPS tracking (foraging behavior) and plasma metabolites (nutritional biomarkers) when studying thick-billed murres ( Uria lomvia ; N  = 237), a colonial-nesting seabird where central place foraging constraints are expected to be particularly pronounced due to high transit costs. Foraging range decreased when birds were constrained to visit the central place several times per day (chick-rearing) compared to self-feeding (incubation), illustrating the constraint of central place foraging. Moreover, adult feeding frequency, as determined by plasma triglycerides, were higher during incubation, consistent with the longer fasts (incubation shifts) during that period. Transit time (foraging distance) increased with date during chick-rearing but not incubation, consistent with prey depletion due to central place foraging within the restricted chick-rearing foraging range. During late chick-rearing, when a diet switch to low-quality, smaller prey occurs, birds switched to foraging near the colony, consistent with the foraging range being overextended. Unlike other, smaller colonies where foraging success is higher due to a smaller halo, sexes had similar foraging behaviour in our study, except during early incubation when females foraged more (more flying, more swimming) as they overcame the cost of producing the egg. When we take our results with other lines of evidence (increased foraging distance with colony size, prey switching as birds “feed down the food chain”), we conclude that central place foraging seabirds may cause prey depletion at one of the world’s largest murre colonies.