Revista Chilena de Historia Natural 77 (2): 219-225, 2004
RESEARCH ARTICLE
Water economy of three Cinclodes (Furnariidae) species inhabiting marine and
freshwater ecosystems
Birds living in desert environments have been the preferred models for the study of
physiological adaptations to water scarcity. Passerine birds living in marine coastal habitats face similar problems, yet physiological
adaptations to water conservation in such species have been poorly documented. We measured total evaporative water loss (TEWL)
and rates of oxygen consumption (VO<sub>2</sub>) in three species of passerine birds dwelling in marine and fresh water
habitats. Mass specific total evaporative water loss was significantly lower in the marine species, Cinclodes
nigrofumosus, than in species inhabiting areas near freshwater sources. We found a positive relationship between TEWL and
VO2. The ratio of TEWL to VO<sub>2</sub> (relative evaporative water loss, RTEWL) showed significant variation among
Cinclodes species, and was highest for the fresh-water living species, C. oustaleti and C.
fuscus. The variation in TEWL found in Cinclodes is likely a consequence of differential exploitation of marine prey
with high osmotic loads, which, in turn, may impose the need for water conservation.
Key words:
evaporative water loss,
Cinclodes, osmoregulation, passerines, salt
