Evolution of Clutch Size in Birds: Adaptive Variation in Relation to Territory Quality

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Science  05 Dec 1980:
Vol. 210, Issue 4474, pp. 1148-1150
DOI: 10.1126/science.210.4474.1148


Reproductive output from enlarged or reduced magpie broods showed that each female generally lays a clutch of optimal size. This size varies considerably between females. Approximately 85 percent of the within-years variation in clutch size was associated with differences between territories. Colonial bird species, lacking individual foraging territories, have a smaller clutch size variation than territorial species.