Birds in marine and saline environments: living in dry habitats

Sabat P.

Abstract

For birds, saline environments such as maritime and salt marsh habitats are essentially dry habitats. When birds drink saline water or consume salt-loaded preys, the osmolarity of their body fluids increases. In order to maintain the osmotic equilibrium, they have to eliminate the excess of electrolytes ingested with preys or water. Marine birds use salt glands, which produce excretion solutions more concentrated than seawater to eliminate excess salt. The physiology and phenotypic plasticity of nasal glands appears to be correlated with the ecological features of species. Birds can also minimize osmotic stress by choosing hypo-osmotic preys, preys with reduced water content, and/or by decreasing salt intake. Although the kidney of birds is clearly less efficiently in its capacity to concentrate the urine than that of mammals, there are interspecific differences in renal structure and physiology that may be correlated with the birds ecological habits, and hence to represent adaptive mechanism to prevent water loss. The kidney may be especially important in taxa that lack active salt gland, such as passerines. Passerines, which are supposed to have limited ability to use saline habitats, include several marine and salt-marsh species. In this review I show that the interaction of the kidney and rectum in osmoregulatory physiology, coupled with selective feeding behavior play a major role in the maintenance of water and salt balance of passerines living in salty environments.

Más información

Título según WOS: Birds in marine and saline environments: living in dry habitats
Título según SCIELO: Birds in marine and saline environments: living in dry habitats
Título de la Revista: Revista chilena de historia natural
Volumen: 73
Asunto: 3
Editorial: Sociedad de Biología de Chile
Fecha de publicación: 2000-01-01
Página de inicio: 401
Página final: 410
Idioma: English
DOI/URL:

10.4067/S0716-078X2000000300004

Identificador: 10.4067/S0716-078X2000000300004
Notas: ISI, SCIELO