Camera traps provide valuable data to assess the occurrence of the Great Curassow Crax rubra in northeastern Costa Rica

Abstract

The Great Curassow (Crax rubra) is an endangered species in Costa Rica due to habitat loss and hunting pressure. Little is known about the spatial ecology of cracids and there is a need to assess their distribution to establish efficient conservation strategies. In this study, we integrated camera trapping data with occupancy models to examine landscape factors that affect the distribution of the Great Curassow in the San Juan-La Selva Biological Corridor in Northeastern Costa Rica. We established remote camera traps at 38 sites within the corridor between July 2009 and July 2011. The Great Curassow was detected on 56 occasions at 19 of the 38 sites. Eight of the 19 occupancy models contained plausible support to predict Great Curassow occurrence, but distance to villages and forest cover were the most important factors positively related to their occurrence. These results suggest the distribution of the Great Curassow is largely susceptible to forest loss and human disturbance in the corridor. Both camera traps and occupancy analyses are useful tools to study medium to large terrestrial birds in the Neotropics.

Determining the factors that influence the occurrence of Bare-faced Curassows (Crax fasciolata) in Humid Chaco, northern Argentina

“…If we dissect our results according to rivers, occupation was greater than 0.50 at about 2.5 km from Colonia Dalmacia (100 inhabitants) and about 10 km from Mojón de Fierro (3000 inhabitants). This may be due to increased hunting pressure, selective logging, and other disturbances that affect availability of resources and structure of forests (Bennett and Robinson 2000, Putz et al 2000, Azevedo-Ramos et al 2006, Pardo et al 2017. Our results agree with a recent review by Benitez-Lopez et al (2017), who analyzed 176 studies conducted in the tropics and found that game bird populations are depleted, on average, within 7 km of populated areas.…”

“…Village distance explained much of the occupancy because it was a good proxy for the two main threats that the Bare-faced Curassow faces along the gallery forest of the rivers. In other studies, distance to populated areas has been used as a variable of occupancy, assuming that distance can be an indirect measure of anthropic effects on wild animal populations (Arroyo-Rodríguez et al 2008, Marinho et al 2018, Pardo et al 2017. However, in our work, we were able to measure these effects and confirm the direct relationship between hunting and selective logging with village distance.…”

“…We also found that the decrease in forest cover negatively affected occupancy by Bare-faced Curassows along the rivers. Most species of cracids are threatened by human activities, including hunting (Barrio 2011, Kattan et al 2015, as well as by forest loss and fragmentation (Melo-Vásquez et al 2008, Thornton et al 2012, Pardo et al 2017). However, Kattan et al (2015) suggest that hunting is the main threat to cracids.…”

“…Following the criterion of Pardo et al (2017) in which a species ceases to be rare when occupation is greater than 50%, the Barefaced Curassow ceases to be rare (Ψ> 0.50) only after 7 km from small villages. If we dissect our results according to rivers, occupation was greater than 0.50 at about 2.5 km from Colonia Dalmacia (100 inhabitants) and about 10 km from Mojón de Fierro (3000 inhabitants).…”

Secondary forest is utilized by Great Curassows (Crax rubra) and Great Tinamous (Tinamus major) in the absence of hunting

“…The male-biased capture ratio of Great Curassows in our study supports the success of programs to eliminate hunting at Osa Verde. Given their striking bill coloration and easy detection during mating displays, males are more easily detected and killed by hunters (Pardo et al 2017). Consequently, where hunting is present, sex ratios are typically skewed toward females (Martínez-Morales et al 2009, Pardo et al 2017.…”