The Breeding Seasons of Southern Hemisphere Birds in the Northern Hemisphere

Summary. Most Southern Hemisphere birds breed in the Southern Hemisphere spring and summer. Imported specimens of most of these species change their rhythm so as to breed in the northern spring and summer in the Northern Hemisphere. Some Southern Hemisphere birds breed in the Southern Hemisphere winter (or very early spring). Imported specimens change their rhythm so as to breed in the northern winter in the Northern Hemisphere.Dromiceius movæ‐hollandiz(Emu) andCereopsis n,‐hollandiz(Cape Barren Goose) examples. Some Southern Hemisphere birds with a restricted breeding season in their native land breed all the year round (or at any time of year) when imported into the Northern Hemisphere.Chempis atratu(Black Swan) is an example. Some Southern Hemisphere birds tend to breed in the same calendar months when imported into the Northern Hemisphere as the members of species in their native land. Examples arePlatycercus cenustus(Northern Rosella Parrot),Melopsittucus undirlatus(Budgerygah), andPoëphila gouldiæ(Gouldian Finch). Imported specimens of these species exhibit an internal rhythm in breeding seasons, not, easily influenced by the environment.