Mesh size and bird capture rates in shasha forest reserve, ile-ife, Nigeria

Few studies have been conducted to verify how mist net mesh size affects the capture rates of birds in Nigeria. This research was undertaken from 06.30 to 18.30 hours between February 2010 and January 2011 at Shasha Forest Reserve (4o20' to 4o40' E, 7o00' to 7o 10' N) near Ile-Ife in southwestern Nigeria, to verify how mesh size affects the capture rates of birds and the efficiency or otherwise of the mist nets involved. Bird species occurrence was recorded using eight nylon mist nets each of 36mm and 61mm mesh sizes in linear transects. The linear transects cuts across different vegetational types with varying degrees of human disturbance. A total of 970 birds were captured and made up of 584 (60.2%) with 36mm mesh and 386 (39.8%) with 61mm mesh. Of the 106 species mist-netted 93(87.7%) were caught by 36mm while 61mm caught 73(68.9%). The 36mm mesh net was more effective for birds with less than 200mm body length while 61mm mesh was more effective for birds with more than 250mm body length. However, both meshes were suitable for birds between 151 and 200mm long. Thirty six millimeter mesh net captured most of the birds below 20g while 61mm mesh captured was more efficient for the larger species. Both mesh sizes were effective for birds with body weights between 41.00 and 80.00g. Deployment of both nets will provide an improvement of abundance estimates for some larger species. By using only 36mm mesh nets, there may be an improvement in the capture rate of small birds and similarly 61mm mesh would substantially improve the capture rate of bigger and heavier birds.