Winter conditions influence biological responses of migrating hummingbirds

Catherine H. Graham, Sarah R. Supp, Donald R. Powers, Pieter Beck, Marisa C.W. Lim, Anusha Shankar, Tina Cormier, Scott Goetz, Susan M. Wethington

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Conserving biological diversity given ongoing environmental changes requires the knowledge of how organisms respond biologically to these changes; however, we rarely have this information. This data defciency can be addressed with coordinated monitoring programs that provide feld data across temporal and spatial scales and with process-based models, which provide a method for predicting how species, in particular migrating species that face different conditions across their range, will respond to climate change. We evaluate whether environmental conditions in the wintering grounds of broad-tailed hummingbirds inffuence physiological and behavioral atributes of their migration. To quantify winter ground conditions, we used operative temperature as a proxy for physiological constraint, and precipitation and the normalized difference vegetation index (NDVI) as surrogates of resource availability. We measured four biological response variables: molt stage, timing of arrival at stopover sites, body mass, and fat. Consistent with our predictions, we found that birds migrating north were in earlier stages of molt and arrived at stopover sites later when NDVI was low. These results indicate that wintering conditions impact the timing and condition of birds as they migrate north. In addition, our results suggest that biologically informed environmental surrogates provide a valuable tool for predicting how climate variability across years inffuences the animal populations.

Original languageEnglish (US)
Article numbere01470
Issue number10
StatePublished - Oct 1 2016
Externally publishedYes


  • Broad-tailed hummingbird (Selasphorus platycercus)
  • Climate change
  • Coordinated monitoring programs
  • Extreme weather events
  • Operative temperature
  • Physiological model
  • Remote sensing

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology


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