Bird population studies in Puerto Rico using mist nets: general patterns and comparisons with point counts

Abstract

Mist nets have been used to monitor site, composition, and survival rates of bird populations in the Guanica Forest of Puerto Rico every winter since 1972. Each line of nets consists of 16. 12-m nets erected end-to-end in a straight line and operated from dawn to dark for three consecutive days. Here we examine features of the netting protocol that could affect quality of results for population studies, including species sampled, length and frequency of netting sessions. and number of captures and recaptures. Point counts and mist-net samples gave very different results for relative abundance of species. Number of birds captured for the first time wiithin a sample declined rapidly over three days of netting, with few birds captured the third day, regardless of a species abundance. Net avoidance was strong within 3-day samples, but not between different netting sessions (which were at least three months apart). We suggest these samples are indicative of avian populations resident within the area of net lines, and that three days is a sufficient length of time to capture the majority of bird using that area, at least in the low-statured vegetation of Guanica Forest. However, in more diverse or structurally complex habitats, mist nets may not sample as large a proportion of the species and individuals present.

Citation

Faaborg, John; Arendt, Wayne J.; Dugger, Katie M. 2004. Bird population studies in Puerto Rico using mist nets: general patterns and comparisons with point counts. Studies in Avian Biology 29:144–150.