Avian brood patch temperature: Relationships with female body mass, incubation period, developmental maturity and phylogeny

Brood patch temperatures (BPT) of 76 species of birds were collated from the literature and compared with female body mass (FBM) and incubation period (Ip) of the species concerned.Correlations between BPT and FBM and Ip were associated with phylogenetic relatedness at a high taxonomic level (Order). BPT was highest in species producing altricial hatchlings, intermediate for precocial species and lowest for semi-precocial species.BPT was higher than embryo and egg temperatures reported in the literature implying that the process of heat transfer during contact incubation is unable to raise embryo temperature to core body temperature.