The comparative breeding biology of magpies Pica pica in an urban and a rural habitat (Aves: Corvidae)

The breeding biology of magpies in an adjacent urban and rural area in the same year was compared. Breeding commenced earlier in the urban habitat. This was attributed to the earlier availability of invertebrate food in the urban habitat as a result of higher urban ambient temperature. Hatching success and the amount of nest predation were lower in the urban area than in the rural area. Low levels of nest predation in urban areas were due to reduced human predation and probably to the relatively low numbers of many natural predators. Differences in the nest tree species utilized also influenced the probability of human predation. Despite these differences in the causes of egg and chick mortality, the number of young reared to 14 days of age per nest was similar in both habitats.