Determination of animal power consumption by indirect calorimetry relies upon accurate estimation of the thermal equivalent of oxygen consumed or carbon dioxide produced. This estimate is typically based upon measurement or assumption of the respiratory quotient (RQ), the ratio of CO2 produced to O2 consumed. This ratio is used to indicate the mixture of lipids, carbohydrates and proteins in th...

We used the doubly labeled water (DLW) method to measure field metabolic rate (FMR) and water turnover during winter and summer in a very small (6.5 g) insectivorous desert passerine bird, the verdin (Auriparus flaviceps). Concurrently, we monitored weather conditions and used time-activity budget data of free-living birds and laboratory data on resting metabolic rate to construct time-activity...

A phylogenetic analysis of Xyphon was completed using 45 adult morphological characters and 1,076 base pairs of the mtDNA gene NADH dehydrogenase 1. Multiple specimens, representative of the range of morphological variation found in each previously described species, were scored for the morphological data matrix to test the monophyly of each species. These tests supported the following synonymi...