Humidity levels in the nests of incubating canaries ( Serinus canarius)

Abstract

1. 1. Vapor pressure in the nest cups ( P N ) of common canaries Serinus canarius averaged 12 torr, but varied considerably both between and within nests during 4–6 consecutive days of incubation. 2. 2. Much of this variation (73–95%) could be accounted for by concurrent variations in ambient humidity ( P 1) around the nest. 3. 3. The estimated amount of water (12.6% of the egg's initial mass) lost by canary eggs during 13 days of incubation under conditions of P N that existed in this experiment is not significantly different from the amount (18.8%) that would be lost if P N = P 1. 4. 4. These data indicate that canaries do not keep the P N constant by ventilating the nest cup while incubating.