Captive breeding, handling and care, and the impact of releases on wild populations
Résumé
In this chapter, we review the way captive breeding of the little bustard is currently being carried out. Indeed, among the various conservation strategies that have been tried to reverse bustard declines, captive breeding, with reintroduction or reinforcement of local populations (“supportive breeding”), has commonly been used. After a brief review of the current captive breeding programmes in other bustard species, we focus on the little bustard reinforcement programme that has been ongoing in France since 2005. We detail the legal requirements, building equipment, and facilities required for a captive breeding centre. We then consider the results obtained between 2005 and 2019 within the three little bustard breeding centres in France in regard to egg collection, hatching success, rearing, fledging success, fledgling release and recovery rates. We also look at the impacts on wild populations, in respect of egg collecting for captivity and reinforcement of a recipient population. Over the last 10 years hatching success has declined (by c.10%, including infertile eggs) in relation to egg size, possibly as a result of senescence in females and/or males, as documented for the houbara bustard. There is some (but not significant) support of female or male senescence pattern in the number of eggs laid, the only parameter investigated here. The most critical issue is the release phase, where the rate of predation of captive-born fledglings is unacceptably high. Post-migration survival was, however, quite high (c.45%) in the first phase of the project (2005–2009), when many of the fledglings originated from wild nests but is currently far lower, c.15%.