Notes on the breeding biology of common resident birds in an urbanized area of Hidalgo, Mexico.

We present data on the breeding biology and nest site characteristics of the six most frequent nesters in a small ecological reserve immersed in the city of Pachuca, Hidalgo, Mexico: Columbina inca (Inca Dove), Pyrocephalus rubinus (Vermilion Flycatcher), Campylorhynchus brunneicapillus (Cactus Wren), Toxostoma curvirostre (Curve-billed Thrasher), Pipilo fuscus (Canyon Towhee), and Carpodacus mexicanus (House Finch). We followed 65 active nests, mainly of C. mexicanus and C. brunneicapillus; density of nests reached up to 15 nests ha-1 in some areas of the park. The main causes of reproductive failure in the failed nests (74%) were heavy storms and human disturbance. Nests were found on seven plant substrates, mainly on Cylindropuntia imbricata and Cupressus spp. Data on nest site characteristics, including the plants used for nesting, their average height and dbh, average height of the nest, clutch size, extent of the breeding season, and particular causes of nest failure is presented for each species. At the end we suggest some general management recommendations that will aid in the conservation of breeding birds in parks of central Mexico.