Female Chaffinch. Garden bird species which nest close to houses are protected to some degree from nest predation by Crows, Magpies and Jackdaws. Those species which nest in field hedges, which are often closely trimmed nowadays, are more vulnerable. Species like Bullfinches, Yellowhammers, Corn and Reed Buntings have disappeared locally over the last generation. Agricultural practices remain largely unchanged, but the huge rise in corvid numbers, along with those of Sparrowhawks and the artificially high local population of Red Kites all serve to reduce the numbers of these once familiar native species.