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Breeding success of the Great Bustard Otis tarda in Zamora Province, Spain, in 1984
Author(s) -
ENA VICENTE,
MARTINEZ ANA,
THOMAS DAVID H.
Publication year - 1987
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/j.1474-919x.1987.tb03180.x
Subject(s) - bustard , hatchling , hatching , nest (protein structural motif) , biology , fecundity , avian clutch size , predation , population , sex ratio , zoology , ecology , reproduction , demography , habitat , biochemistry , sociology
Great Bustards are still fairly abundant (5‐2 nests/1000 ha) in Zamora. Overall fecundity was high (92% of adult females attempt to nest; 2–47 eggs/clutch; 89% egg fertility), but pre‐ and post‐hatching mortality were also high (50% of eggs laid; 57% of nestlings hatched), due mainly to agricultural machinery but also to natural predators. Calculated annual yields per 100 adult females were: 227 eggs, 102 hatchlings, 44 fledglings. Production of 44 fledglings/y could sustain a stable adult population (mortality approx. 8%/y) if mortality of immatures is not more than 18–22%/y.