Ex situ conservation of the Bengal florican 911


FIG. 3 Numbers of free-living adult female Bengal florican established by captive breeding and release (dark lines) or by a strategy of in situ conservation only (pale grey lines) alive in each programme year (1–50), under two scenarios of in situ conservation: current situation (solid lines), likely future situation (dashed lines). Per cent of model runs under which no birds were able to be released (failed to release) and probability of extinction of the ex situ programme (PEP) after 50 years are indicated.


survived to mid 2020 (at least) except for one female that had been missing a leg. Weekly carcass surveys recorded two Bengal florican mortalities (one male and one female) during May 2019–June 2020, so the 2019 egg collection plan was resumed in Stoung-Chikreang Bengal Florican Conservation Area in 2020. Samples will be taken from all captive individuals for molecular genotyping to determine relatedness so that we can design a captive breeding pro- grammethatmaximizes fitness of offspring (Hogg et al., 2018).


Discussion


Conservation managers are increasingly forced into a situ- ation in which they are ‘held in the pressured space between extinction (as a limit on numbers and time) and the fragile wild (as a limit on intervention). Fail to intervene, and the object is lost; intervene, and the object may also be lost, although in other ways’ (Reinert, 2013,p. 22). Formany spe- cies, given the numbers of individuals available to be taken into captivity, and differences in selective pressure between captive and wild birds, it is inevitable that captive popula- tions will differ from those in the wild (Frankham, 2008; Robert, 2009) even with careful genetic management of the captive flock (Williams & Hoffman, 2009; Witzenberger & Hochkirch, 2011). Such changes in birds include reduced brain volume of captive-bred waterfowl compared with wild birds (Guay & Iwaniuk, 2008), reduced vigilance (Carrete & Tella, 2015) and inappropriate behavioural responses to predators (Griffin et al., 2000).


The first questions about captive breeding are therefore


philosophical: given the genetic, morphological and behav- ioural changes induced by captivity, conservation managers and those who support them must be satisfied that the birds that may eventually be reintroduced to the wild are approxi- mate surrogates of the former wild populations, especially if they cannot be returned to their native range. These con- cepts are rarely considered explicitly in advance of ex situ conservation, but deeply-held opinions on what it means for an animal to be wild may be revealed at a stage when they can derail the process of ex situ conservation. For ex- ample, effective conservation of the California condor was delayed for several years because the prevailing ideology favoured a hands-off approach, until a change in manage- ment brought all remaining individuals into captivity and eventually reversed population declines through releases of captive-bred birds (Snyder & Snyder, 2000). In another example, those operating captive management of the alalã (Hawaiian crow) Corvus hawaiiensis, which is extinct in the wild, have decided to teach the crows to behave in a simi- lar way to the original forest dwelling alalã (although their habitat is different since the arrival of the feral pigs that caused them to go extinct), rather than training them to become a human commensal, as many wild populations of other crow species have done of their own volition (van Dooren, 2016). A different approach has been taken with captive-bred


Asian houbaras, which have lower fecundity, a docile tem- perament and differences in migration behaviour com- pared to wild-bred birds (Villers et al., 2010; Dolman


Oryx, 2021, 55(6), 903–915 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319001510


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