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Analysis of Nest Record Cards reveals altitudinal and habitat differencesbetween these two species. The resident or partially migratory Stonechat has a longer breeding season (with a potential for rearing three broods) than the Whinchat which is a trans-Saharan migrant and arrives later. It is suggested that the greater productivity of the Stonechat might counterbalance a higher winter mortality.
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Fuller et al. (1977) studied this question.
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