Patterns of incubation and nest‐site attentiveness in relation to organochlorine (PCB) contamination in glaucous gulls

摘要: Summary 1. Although experimental studies show that organochlorines (OC) can affect bird behaviour, field assessments are invariably confounded by ecological differences between contaminated and uncontaminated sites. The behaviour of individual birds in the has rarely been related to contaminant burden. 2. We examined patterns incubation nest-site attentiveness relation OC burden, measured as polychlorinated biphenyl (PCB) concentration blood, 27 glaucous gulls Larus hyperboreus two breeding areas at Bear Island, north-eastern Atlantic. 3. Blood PCB concentrations ranged from 52 ng g - 1 1079 (wet weight). There were significant areas, females had signi ficantly lower than males. 4. Gull differed significantly sexes independently PCB. Females incubated more males (54% vs. 46%) but spent time away nest site males, both overall (23% 12%) when not incubating (50% 21%). They also absent for longer periods (4·5 2·8 h). Moreover, length bouts (6·4 4·4 h), amount (51% 25%) absences (5·6 1·8 h) probably due different feeding specializations. 5. After controlling these area sex effects, proportion incubating, number absences, blood 6. Increased absence with high suggests effects on reproductive behaviour. speculate endocrine disruption or neurological might be involved, leading increased energetic costs during reduced output.