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Summary
Zack, S. 1986. Breeding biology and inter-territory movements in a Fiscal Shrike population in Kenya. Ostrich 57: 65–74.
A colour-banded population of Fiscal Shrikes Lanius collaris was studied for two-and-a-half years near Lake Naivasha, Kenya. Annual survival was 39%, but since 25% of the colour-banded adults were known to have resided in two or more territories, this probably is an overestimate of mortality, because of dispersal outside the study site. I detected no sexual differences in survival. The study site contained from five to 1 pairs. Young birds fledged from only 15% of the nests I found. Only eight of the 17 pairs studied produced any young; these eight pairs averaged 1,89 young per nest. The amount of time the breeding female incubated or brooded young was related to the number of prey items brought to the nest by the breeding male. Males brought 26% of their captured prey to the nest, and the items brought were biased toward the longer prey items. Small prey items were rarely brought to the nest. Juveniles were independent of parental feeding by 50 days post-hatching. Juveniles left the natal territory after five months.