Breeding Biology and Success of a Reintroduced Population of the Critically Endangered Puaiohi (Myadestes Palmeri)

Abstract

The ultimate success of reintroduction programs for endangered species depends on the ability of reintroduced animals to breed in the wild. We studied the nesting success and breeding biology of a reintroduced population of Puaiohi (Myadestes palmeri) on the island of Kaua'i, Hawaii. Thirty-four captive-bred Puaiohi were released into the Alaka'i Swamp in 1999-2001 and monitored using radiotelemetry. Ten females and two males paired with wild and other released birds, including one polygynous trio. From March to September, 31 nests were built. Mean clutch size was 2.0 eggs, daily nest survival was 0.97 ± 0.01 (mean ± SE) and overall nest success was 0.40 ± 0.02. We confirmed predation, most probably by rats (Rattus spp.), as the greatest cause of nest failure, occurring at 38% of active nests with known fates, and causing the death of two nesting adult females. Ground-based rodent control proved ineffective at protecting nest attempts. Successful nests fledged an average of 1.4 young each (n = 10), and 85% of fledglings survived at least two weeks. Importantly, breeding behavior and success were comparable to those of wild Puaiohi. This is the first record of breeding in the wild from captive-bred endangered Hawaiian passerines. The ability of captive-bred Puaiohi to survive and breed successfully in the wild bodes well for future releases of this and other endangered passerines, but high predation rates on nests and nesting females highlights the importance of maintaining and restoring safe habitat for recovery. Biología y Éxito Reproductivo de una Población Reintroducida de Myadestes palmeri, una Especie en Peligro Crítico

Breeding ecology and success of a reintroduced population of the endangered Crested Ibis Nipponia nippon

“…The present study provides evidence for the first successful release of captive-reared Crested Ibis, presenting a meaningful model for reintroduction programmes of other endangered species. In the present reintroduction programme, although the survival rate of reintroduced birds was not as high as that of some species such as Puaiohi Myadestes palmeri released to the wild (Tweed et al 2006), two pairs fledged young in their first breeding season after release (Yu et al 2009) and new pair formations continued to occur and the number of fledglings produced continued to increase in the following years.…”

“…The success of reintroduction programmes depended on the quality of the habitat in which the reintroductions took place, the adaptive ability of the birds to new conditions, as well as the number and age structure of the released birds (Griffith et al 1989, Wolf. et al 1996, Armstrong et al 2002, Tweed et al 2006). Generally, it seems to be more difficult to reintroduce migratory species successfully than resident ones.…”

An analysis of translocation regimes for the endangered puaiohi Myadestes palmeri

“…For evaluation purposes, we calculated 2 additional measures from the latter 3 variables: number of harvests/supplements and total number of birds harvested/supplemented. We assumed 90% survival immediately after translocation, as previous releases of captive-bred puaiohi found a 91% 30 d post-release survival (Tweed et al 2006) for primarily juvenile birds. Subsequent releases saw decreasing survival (Switzer et al 2013), though it is possible this was due to the release of older birds or the declining fitness of the captive population.…”

“…Subsequent releases saw decreasing survival (Switzer et al 2013), though it is possible this was due to the release of older birds or the declining fitness of the captive population. We chose to translocate only juvenile birds, as these exhibited the highest survival and integration into the existing population in previous releases of captive-bred puaiohi (Tweed et al 2006, Switzer et al 2013, VanderWerf et al 2014.…”

Guiding the prioritization of the most endangered and evolutionary distinct birds for new zoo conservation programs

“…Nevertheless, captive breeding programs (which for convenience we narrowly define as ex situ conservation in this study) have played a pivotal role in saving numerous threatened bird species from extinction in the wild, providing insurance populations which underpinned later reintroduction or population reinforcement programs (e.g. Tweed et al, ; Walters et al, ; Witteman, Beck, Pimm, & Derrickson, ). Calls have thus been made to increase the number of threatened species held ex situ to improve the conservation value of collections (Conde et al, ).…”