Since birds are warm-blooded, they sit on the eggs to keep them warm. Reptiles and invertebrates are cold-blooded, and so need to keep their eggs in warm places. Sometimes even birds need the help of the Sun.
Many factors may be vital to the incubation. In some reptiles for example, no fixed temperature is necessary. However, the actual temperature determines the sex ratio of the offspring. In birds, by contrast, the sex of offspring is genetically determined, but a constant and particular temperature may be necessary for successful incubation.
- De Marchi G; Chiozzi G. & Fasola M. 2008. Solar incubation cuts down parental care in a burrow nesting tropical shorebird, the crab plover Dromas ardeola. Journal of Avian Biology 39 (5):484–486
- Ekarius, Carol (2007). Storey's illustrated guide to poultry breeds. 210 MAS MoCA Way, North Adams MA 01247: Storey Publishing. ISBN 978-1-58017-667-5.CS1 maint: location (link)