First measurements of metabolic rates in the Stone Curlew, a nocturnal inland wader

Among birds, waders are characterized by high metabolic rates that may be a consequence of the constraints arising from their expensive way of life in unsheltered and windy habitats. Comparative analyses are hampered by the currently poor phylogenetic coverage of the Charadrii suborder: most studies have focused on wader species living on seashores, while only few data are available for inland species. We studied energetic requirements in a nocturnal inland species, the Stone-Curlew Burhinus oedicnemus, belonging to the Burhinidae family, so far never investigated in relation to energetics. Resting metabolic rate (RMR) and metabolic response to temperature of five captive birds were measured in a laboratory using a respirometer chamber. RMR value (1.97 W) was lower than predicted values for Basal Metabolic Rates based on allometric relationships for shorebirds, but close to the general values predicted for all birds. This result is consistent with the hypothesis that RMR may be a consequence of environmental constraints and the low values found in Stone-Curlew may be due to its nocturnal way of life and/or inland habitat in milder climatic conditions than other shorebirds.