Reserva Ecológica Costanera Sur

Sitio realizado por aficionados a la observación de aves desde 10 de enero 2006

Nuptial Plumge

Brown-hooded Gull
Chroicocephalus maculipennis
Gaviota capucho café/Brown-hooded Gull© J. Simón Tagtachian
The breeding season comes and we note that birds are more active. They seem to wake up.There are chases, displays, increase in vocalizations, etc. and there are also changes in their appearance, many of which pass unnoticed to the untrained eye. But the nuptial or alternate plumage leaps to the eye. This gull’s nuptial or alternate plumage is a brown hood which covers its head, which is practically white in its basic (also called winter) plumage.
These changes are due to the preparation of the reproductive system for a new breeding cycle. Environmental factors such as day length, light intensity, temperature, etc regulate the activity of the pituitary gland which segregates the hormones which stimulate these changes. Late in the reproductive season these hormones are inhibited by others which curb all this efervescence till the next cycle.
CR