Breeding biology during establishment of a reintroduced griffon vulture Gyps fulvus population

Published source details Sarrazin F., Bagnolini C., Pinna J.L. & Danchin E. (1996) Breeding biology during establishment of a reintroduced griffon vulture Gyps fulvus population. Ibis, 138, 315-325.
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This study is summarised as evidence for the following.

	Action	Category
	Release captive-bred individuals into the wild to restore or augment wild populations of vultures Action Link
	Release birds as adults or sub-adults, not juveniles Action Link

Release captive-bred individuals into the wild to restore or augment wild populations of vultures

A replicated study over 12 years (Bose & Sarrazin 2007) of the same programme as in Sarrazin et al. 1996 showed that the number of nesting pairs of griffon vultures Gyps fulvus in the release site in southern France increased steadily from three to 33 (fledging a total of 95 young) over 11 breeding seasons following the release of 59 captive-bred birds during 1981–1986. The majority of wild-born and young-released birds nested first at four years old. The effect of the age birds were released at is discussed in ‘Release birds as adults or sub-adults, not juveniles’.
Release birds as adults or sub-adults, not juveniles

A replicated study over 12-years (Sarrazin et al. 1996) of the same programme as in Sarrazin et al. 1994, found that the nesting success of griffon vultures Gyps fulvus released at the age of three or more (0.42 fledglings/pair for 103 nesting attempts) was significantly lower than that of younger releases and wild-bred birds (0.82 young/pair for 11 attempts). This difference was partially due to lower hatching success for older released birds (55% hatching success for 79 eggs), compared with younger releases and wild-bred birds (75% for 11 eggs). The overall success of the programme is discussed in ‘Release captive-bred individuals into the wild to restore or augment wild populations’.