The Gaseous Microclimate of the Avian Nest During Incubation

Abstract

Interest in the gaseous microclimate of the avian nest during incubition has greatly intensified in recent years because of the potentially important effects of micro climatic factors upon embryonic respiration and hydration. Few data are available describing levels of carbon dioxide and oxygen surrounding the eggs. What information is available, however suggests that in most species levels of CO2 and O2 may not differ importantly from that of the general atmosphere. The most likely exceptions to this generalization are tunnel nesting birds. Data quantifying water vapor in the nest are more abundant. Nest humidity varies substantially between species, but there are no apparent correlations between nest humidity and breeding habitit or ambient humidity. Based upon limited empirical data and simulations using a deterministic model it appears that adult regulation of egg dehydration by short-term modificttions of nest humidity may be neither necessary nor effective.