Inter- and intraspecific variation in the use of marine food resources by three Cinclodes (Furnariidae, Aves) species: carbon isotopes and osmoregulatory physiology

Sabat P.; del Rio, CM

Abstract

The avian genus Cinclodes (Furnariidae) includes species that inhabit both inland and marine shores. We compared the carbon isotopic composition and osmoregulatory capacities of field caught individuals of three Cinclodes species in Chile. Cinclodes nigrofumosus is a resident of coastal shores, whereas C. oustaleti and C. patagonicus inhabit both coastal and inland environments. The tissues of C. nigrofumosus exhibited distinctively marine ?13C values, whereas those of C. oustaleti and C. patagonicus were intermediate between marine and terrestrial values. The differences in carbon isotopic composition among these three species were paralleled by differences in osmoregulatory characteristics. The species that carbon isotopes revealed to be strictly marine, C. nigrofumosus, had relatively larger kidneys with a higher fraction of total renal tissue occupied by medullary cones than its congeners C. oustaleti and C. patagonicus. Cinclodes nigrofumosus individuals also produced more concentrated urine. In addition to interspecific differences in osmoregulation, we found intraspecific differences. Cinclodes nigrofumosus collected at an arid site with limited or no available fresh water exhibited larger kidneys and higher relative medullary thickness than individuals collected at a mesic site. Cinclodes nigrofumosus, like all passerines, lacks functional salt glands. This species appears to be unique among passerines in its ability to live in extreme arid coastal environments and to cope with a marine diet that imposes high osmotic loads.

Más información

Título según WOS: Inter- and intraspecific variation in the use of marine food resources by three Cinclodes (Furnariidae, Aves) species: carbon isotopes and osmoregulatory physiology
Título según SCOPUS: Inter- and intraspecific variation in the use of marine food resources by three Cinclodes (Furnariidae, Aves) species: Carbon isotopes and osmoregulatory physiology
Título de la Revista: ZOOLOGY
Volumen: 105
Asunto: 3
Editorial: ELSEVIER GMBH, URBAN & FISCHER VERLAG
Fecha de publicación: 2002-01-01
Página de inicio: 247
Página final: 256
Idioma: English
DOI/URL:

10.1078/0944-2006-00078

Identificador: 10.1078/0944-2006-00078
Notas: ISI, SCOPUS