2 Works

The allometry of daily energy expenditure in hummingbirds: an energy budget approach

Anusha Shankar, Donald R Powers, Liliana M Dávalos & Catherine H Graham
1. Within-clade allometric relationships represent standard laws of scaling between energy and size, and their outliers provide new avenues for physiological and ecological research. According to the metabolic level boundaries hypothesis, metabolic rates as a function of mass are expected to scale closer to 0.67 when driven by surface-related processes (e.g., heat or water flux), while volume-related processes (e.g., activity) generate slopes closer to one. 2. In birds, daily energy expenditure (DEE) scales with body...

Hummingbird torpor in context: duration, more than temperature, is the key to nighttime energy savings

Anusha Shankar, Rebecca J. Schroeder, Susan M. Wethington, Catherine H. Graham & Donald R. Powers
Torpor is an important energy saving strategy in some small birds, but it has rarely been studied in natural field conditions. We compared torpor use across 43 wild-caught individuals of eight hummingbird species across sites with different natural temperature regimes. Most laboratory studies focus on the relationship between metabolic rate and temperature, but our aim was to evaluate what environmental factors most influence hummingbird nighttime energy management under natural conditions. We found that the probability...

Registration Year

  • 2020

Resource Types

  • Dataset


  • George Fox University
  • Swiss Federal Institute for Forest, Snow and Landscape Research
  • Stony Brook University
  • University of Alaska Fairbanks