Indirect predator effects on clutch size and the cost of egg production

• Published in: Ecology letters Vol. 13; no. 8; pp. 980 - 988
• Main Authors: Travers, Marc, Clinchy, Michael, Zanette, Liana, Boonstra, Rudy, Williams, Tony D
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.08.2010; Blackwell Publishing Ltd; Blackwell
• Subjects: adverse effects; Animal and plant ecology; Animal reproduction; Animal, plant and microbial ecology; Animals; aquatic invertebrates; Aves; Biological and medical sciences; Birds; Birth rate; breeding; Clutch Size; cost of reproduction; Demography; Ecology; Egg production; Female; females; Food availability; Fundamental and applied biological sciences. Psychology; General aspects; Invertebrates; Mammals; nest predation; Nesting Behavior; nests; non-consumptive effects; Oxidative stress; Physiology; Population Dynamics; Predation; predator-prey ecology; Predators; Predatory Behavior; Prey; Reproduction; Reproduction - physiology; risk; Risk factors; Sparrows; Sparrows - physiology; Predator prey relation; Oxidative stress; Costs; Egg; Ecology; cost of reproduction; Clutch size; non-consumptive effects; predator—prey ecology; egg production; Reproduction; nest predation; Predator; Predation; Nest; Reproductive potential
• ISSN: 1461-023X; 1461-0248; 1461-0248
• DOI: 10.1111/j.1461-0248.2010.01488.x

Ecology Letters (2010) 13: 980-988 Predator-induced changes in physiology and behaviour may negatively affect a prey's birth rate. Evidence of such indirect predator effects on prey demography remains scarce in birds and mammals despite invertebrate and aquatic studies that suggest ignoring such effects risks profoundly underestimating the total impact of predators. We report the first experimental demonstration of indirect predator effects on the annual 'birth' rate resulting from negative effects on the size of subsequent clutches laid by birds. We manipulated the probability of nest predation and measured the size of subsequent clutches and multiple indices of the mother's physiological condition, while controlling for food availability, date and stage of breeding. Females subject to frequent experimental nest predation laid smaller subsequent clutches and were in poorer physiological condition, particularly regarding non-resource-based indices (e.g. oxidative stress and glucocorticoid mobilization) consistent with both a response to the threat of predation and an increased cost of egg production.