Elevated concentrations of naturally occurring heavy metals inversely correlate with reproductive output and body mass of the Kagu Rhynochetos jubatus |
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| Authors: | Jörn Theuerkauf Tokushi Haneda Yuji Okahisa Nozomu J. Sato Sophie Rouys Henri Bloc Keisuke Ueda Izumi Watanabe Ralph Kuehn Roman Gula |
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| Affiliation: | 1. Museum and Institute of Zoology, Polish Academy of Sciences, Warsaw, Poland;2. Laboratory of Environmental Toxicology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan;3. Department of Life‐Sciences, Rikkyo University, Toshima, Tokyo, Japan;4. Japan Bird Research Association, Fuchu, Tokyo, Japan;5. Conservation Research New Caledonia, Nouméa Cedex, New Caledonia;6. Syndicat mixte des Grandes Fougères, Farino, New Caledonia;7. Unit of Molecular Zoology, Chair of Zoology, Department of Animal Science, Technische Universit?t München, Freising, Germany;8. Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las 9. Cruces, NM, USA |
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| Abstract: | To assess the effects of naturally occurring heavy metals on wild birds, we compared reproductive success and heavy metal contents in feathers of Kagu Rhynochetos jubatus living on ultramafic (rich in heavy metals) soil with those of Kagu living on non‐ultramafic soil. From 2003 to 2016, we monitored breeding of 19 Kagu families by radiotracking and video‐monitoring, and collected rump down feathers from 69 wild Kagu. The metal concentrations in Kagu feathers correlated with the concentrations in the soil. The mean numbers of eggs laid and fledglings per year of Kagu families on non‐ultramafic soil were about four times higher, and home‐ranges three times smaller, than those of Kagu on ultramafic soil. Mass of eggs and the proportion of eggs that developed to fledglings were similar in the two areas, whereas the mass of adult Kagu on non‐ultramafic soil was nearly 10% higher than that of adult Kagu living on ultramafic soil. The impact of naturally occurring heavy metals on Kagu breeding productivity and body mass appears to act through their effects on food supply rather than being caused directly by metal toxicity. The results imply that conservation of Kagu might be more effective in non‐ultramafic areas, as populations can recover much faster on these soils and Kagu can then recolonize and bolster populations in ultramafic areas. |
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| Keywords: | bird breeding success suboptimal habitat ultramafic soil |
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