Factors affecting forest bird diversity and recent avifaunal changes in the degrading Kagoro-Nindam forest reserves, Kaduna, Nigeria

The Kagoro-Nindam forest reserves in Nigeria harbour several forest bird species, although the area is well away from the main forest zone of the country. A bird survey in the Chanji forest reserve in this area found more species than earlier surveys. This is largely due to an influx of non-forest species, probably the result of habitat destruction. Correlations between vegetation variables and species diversity showed that loss of canopy cover, due mainly to logging, appeared to be the major cause of the changes.