You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Energetics and Water Balance in Free-Living Tropical Hummingbirds
Wesley W. Weathers and F. Gary Stiles
Vol. 91, No. 2 (May, 1989), pp. 324-331
Published by: American Ornithological Society
Stable URL: http://www.jstor.org/stable/1368310
Page Count: 8
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
In Costa Rica's humid, Caribbean lowlands, we used the doubly-labeled water (DLW) technique to measure field metabolic rate (FMR) and water influx of free-living Crowned Woodnymphs (Thalurania colombica) (mean mass = 4.90 g) and Bronze-tailed Plumeleteers (Chalybura urochrysia) (mean mass = 7.23 g). FMR averaged 37.9 kJ/day in woodnymphs (n = 9) and was 57.9 kJ/day in a single plumeleteer. The former value is 26% higher than expected from the birds' mass, based on other DLW studies. Water influx averaged 2,392 ml/(kg·day) in woodnymphs (n = 12) and 2,001 ml/(kg·day) in plumeleteers (n = 2). These are the highest water flux rates measured for any bird and are equivalent to turning over, respectively, 366% and 304% of the birds' total body water content each day.
The Condor © 1989 Cooper Ornithological Society