Using post-release monitoring data to optimize avian reintroduction programs: a 2-year case study from the Brazilian Atlantic Rainforest

Abstract

Post-release monitoring data of reintroduced captive-bred birds can be utilized to help optimize future avian reintroduction programs. We present a case study of broad interest to reintroduction and conservation biologists interested in investigating movements and habitat use by reintroduced captive-bred birds. We used radio telemetry to monitor reintroduced captive-bred red-billed curassow Crax blumenbachii at a private reserve, Rio de Janeiro state, Brazil. During August 2006 and October 2008, 25 radio-tagged individuals (15 females and 10 males, all o30 months old) were monitored over a 25-month period. Evaluation of home-range size and habitat use revealed that captive-bred curassows should be released only into forest areas with adequate riverine habitat that are larger than the minimum home-range movements of the proposed population. Curassows also utilized pastureland, cultivated areas and secondary forests, suggesting that the proximity of release sites to such habitats may not be entirely detrimental for future reintroductions. Site fidelity for reintroduced birds was low, and there was a tendency for resident curassows to move away when new cohorts were released into the area. Determining how habitat characteristics, displacement by newly released cohorts, adjustments to their new surroundings or cohort social interactions influence post-release movements of resident birds at release sites over prolonged time frames would improve our knowledge on the impacts of releasing further captive-bred individuals into habitats with extant populations. Critically, the movement patterns of reintroduced curassows identified in this study demonstrate that avian post-release monitoring must be considered over an appropriate time frame and we highlight how different conclusions may be generated depending on the duration of post-release monitoring. It may take more than 2 years for reintroduced captive-bred sub-adults to become established following release and that post-release monitoring of similar duration may not be adequate for large avian species such as Cracids.

Post‐reintroduction distribution and habitat preferences of a spatially limited island bird species

“…This study and others (e.g. van Heezik, Maloney & Seddon, 2009;Bernardo et al, 2011) also show that success rates of reintroductions can be improved by using post-release monitoring data to discern habitat constraints. Here, we use long-term post-release data to investigate habitat use and preferences of a threatened bird species that was reintroduced to a predator-free island in the 1980s.…”

Coarse- and fine-scale patterns of distribution and habitat selection places an Amazonian floodplain curassow in double jeopardy

“…On the basis of the smallest home range size of the four estimators we used, our three C. globulosa showed a larger mean home range size (283 ha) than other species of curassows studied to date with telemetry: C. daubentoni 149–197 ha ( Bertsch & Barreto, 2008 ), C. alector 185 ha ( Bernal & Mejía, 1995 ), C. blumenbachi 125 ha ( Bernardo et al, 2011 ), and M. salvini 72–155 ha ( Santamaría & Franco, 1994 ; Parra et al, 2001 ). The relatively low success of our trapping effort and subsequent small sample size, in terms of numbers of individuals, emphasises the practical difficulties in studying rare species in complex habitats.…”

“…Five different estimators were used to calculate home range size for comparison with other cracid studies: minimum convex polygon (95% MCP), fixed kernel (95% FK), Brownian bridge movement model (95% BBMM), and adaptive local convex hull (95% aLoCoH). We used a Kruskall–Wallis test to test for differences between home range sizes generated by the different estimators, using low sensitivity to extreme values and low amplitude as criteria for selecting the most representative estimators ( Bernardo et al, 2011 ). We estimated home range sizes throughout the full year of monitoring and used a Wilcoxon signed-rank test to test for differences between dry and wet seasons.…”

Perfil Dos Fragmentos De Mata Atlântica Com Registros Do Mutum-Do-Sudeste

“…No entanto, esse cenário não foi observado em todos os locais em que há registro atual da espécie, como na área Capitão. Alguns autores citam o uso de plantações pelo mutum-do-sudeste, situadas próximas a casas na zona rural onde a pressão de caça é baixa (ALVAREZ;DEVELEY, 2010;BERNARDO et al, 2011). Contudo, a frequência de forrageio em áreas próximas a casas é baixa, mesmo por espécies de cracídeos mais resilientes a um certo nível de modificação no habitat, como é o caso de Penelope superciliaris (MIKICH, 2002).…”

“…Avaliaram-se diferentes variáveis considerando a área interna do polígono de mata (escala de mancha) e as áreas de influência de 2 km, 1 km e 500 m de raio (escala de paisagem). A área máxima de influência (2 km) foi considerada com base na distância média entre as áreas de vida dos casais de Crax blumenbachii nativos e reintroduzidos, que variou de 2 a 3 km (SICK, 1997;BERNARDO et al, 2011). Para não haver sobreposição da área de vida decidiu-se analisar a resposta da espécie numa escala <3 km no entorno de cada área estudada.…”