Effects of supplemental calcium on the reproductive output of a small passerine bird, the house wren (Troglodytes aedon)
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Published source details
Johnson L.S. & Barclay R.M.R. (1996) Effects of supplemental calcium on the reproductive output of a small passerine bird, the house wren (Troglodytes aedon). Canadian Journal of Zoology, 74, 278-282.
Published source details Johnson L.S. & Barclay R.M.R. (1996) Effects of supplemental calcium on the reproductive output of a small passerine bird, the house wren (Troglodytes aedon). Canadian Journal of Zoology, 74, 278-282.
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This study is summarised as evidence for the following.
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Provide calcium supplements to increase survival or reproductive success Action Link |
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Provide calcium supplements to increase survival or reproductive success
A randomised, replicated and controlled trial in woodland patches in Wyoming, USA (Johnson & Barclay 1996), found that house wrens Troglodytes aedon provided with supplementary calcium did not raise more chicks than control (unsupplemented) birds (5.6 chicks/successful nest for 48 supplemented nests vs. 5.4 for 44 controls). In addition, they did not produce larger eggs or chicks (9.0 cm3/egg and 9.9 g/chick for 53 eggs and 49 chicks from supplemented nests vs. 8.8 cm3 and 9.9 g for 53 and 41 controls) or have larger clutches (6.7 eggs/clutch for 54 supplemented clutches vs. 6.4 eggs/clutch for 56 controls). Calcium was provided in the form of an equal mix of crushed oyster shells and chicken eggshells in small pots attached to the outside of nest boxes. Control nest boxes also had pots attached, but they were not filled.
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