Ndang'ang'a, P.K., Njoroge, J.B.M., Ngamau, K., Kariuki, W., Atkinson, P.W. & Vickery, J. 2013. Effects of crop diversity on bird species richness and abundance in a highland East African agricultural landscape. Ostrich 84: 39. doi:10.2989/00306525.2013.775189