Preliminary approach to the structure of a colony of Natalus tumidirostris (Natalidae) during the rainy season at the Macaregua cave, Santander, Colombia

Abstract

Introduction: We describe the population size and reproductive aspects of a colony of Natalus tumid- irostris during the rainy season of 2013, in the Macaregua cave (6o39’36.2 ‘’ N and 73o0.6’32.3 ‘’ W), Curití, Santander, Colombia. Objective: Estimate the sex ratio, age categories, the reproductive status and population size of a colony of N. tumidirostris in this cave. Materials and methods: The capture of individuals was performed with a handmade harp trap, a modi ed mist net and manual capture. Results: We capture a total of 274 individuals of which were 14 recaptures. The sex ratio during the samplings was 7: 1 (June), 1: 1 (August) and 3: 1 (September). The structure of the colony was a form of inverted pyramid, and reports the presence of a nursery in April. As for the reproductive status of females, some were inactive (42%) and another 58% were preparing for reproductive events (proestrus). No reproductive activity was observed in males. The colony size varies in a range of 1941-3279 individuals. Conclusion: For the months of study no sexual segregation occurs, although there were variations in the sex ratio. The presence of a nursery and the description of the reproductive status of females indicate that the breeding season for this species occurs in the rst months of the year, between January and February. The inverted pyramid may indicate a decline in population size.