Feeding ecology of the Galapagos Hawk after goat eradication

in Neotropical Program: Student Education and Research: Ecuador: Ecology and demography of the Galapagos Hawk:

Status: Active, started in 2009

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Goals:

Determine effects of goat eradication on the feeding ecology of the Galapagos Hawk.

Background:

The subsequent impact of goat eradication on the Galapagos Hawk should be detected by differences in its feeding ecology, pre and post-goat eradication. We predict that the Galapagos Hawk will adapt to its new environment (with reduced herbivory and increased vegetation cover) by shifting its diet composition, from a predominantly ground prey (before goat removal) to a more arboreal prey base (after goat removal). This shift in diet composition should be more drastic in the transition zone (> 200 masl, with more rainfall) rather than in the arid zone (<200 masl). We also predict that the population of introduced rats (Rattus rattus) will increase in abundance due to vegetation recovery, and remain common in the hawk’s diet. The post-goat (2009-2011) eradication diet data will be compared to pre-goat (1999-2000) eradication data collected by the Arkansas State University which indicates that 70% of the total prey biomass delivered at nests consisted of black rats, lava lizards, centipedes and other ground prey, whereas less than 30% consisted of various species of birds.

Recent Results:

2010

  • Hawks were breeding in June- December 2010 and 344 prey deliveries were recorded at 11 nests.
  • Hawks were not breeding in February- May 2010 and no prey deliveries could be recorded.

2009

  • Hawks were not breeding in June-July 2009 and no prey deliveries could be recorded.

Project Links:

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Location Note:

Santiago Island, Galapagos Islands, and Ecuador

Species involved

People involved in this project:

Rick Watson Ph.D. Vice President and Director of International Programs
Hernan Vargas Ph.D. Program director – Neotropical Science and Student Education
Mari Cruz Jaramillo Msc student
Patricia Parker UMSL, University advisor

Cooperating Partners:

  • Arkansas State University
  • Charles Darwin Foundation
  • Galapagos National Park Service
  • Offield Family Foundation
  • Swiss Friends of the Galapagos
  • The Galapagos Conservancy
  • University of Missouri Saint Louis