title: Heavy metal load and dominance hierarchy in juvenile willow tits during winter.
abstract: Possible links between plasma testosterone levels, heavy metal loads and dominance in juvenile male willow tits (Parus montanus) are studied during winter conditions in Norway. Dominant individuals have better access to food resources, significantly higher cadmium content in the liver and higher plasma testosterone level compared to subordinates. A positive correlation was also found between plasma testosterone level and content of cadmium in the liver. Although the results in our study shows only a limited difference in testosterone level of dominant and subordinate juvenile male willow tits, possible small changes in behaviour might have crucial effects on winter survival of these birds.
authors.affiliation: Norwegian University of Science and Technology, Section of Natural History, N-7491 Trondheim, Norway.
authors.forename: Olav
authors.initials: O
authors.lastname: Hogstad
authors.forename: Hans Chr
authors.initials: HC
authors.lastname: Pedersen
mesh_terms: D000374:Aggression; D000818:Animals; D001822:Body Burden; D002104:Cadmium / Q000032:analysis; D004785:Environmental Pollutants / Q000032:analysis*; D008099:Liver / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis*; D012621:Seasons; D012930:Social Dominance; D020308:Songbirds / Q000502:physiology*; D013739:Testosterone / Q000097:blood
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy; D002104:Cadmium; D013739:Testosterone