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.