The distribution and abundance of the smooth-billed ani Crotophaga ani (L.) in the Galapagos Islands, Ecuador
| Autor: | Daniel K. Rosenberg, Marcia H. Wilson, Felipe Cruz |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
education.field_of_study
biology Ecology Seed dispersal media_common.quotation_subject Population Crotophaga ani Introduced species biology.organism_classification Population density Competition (biology) Geography Habitat Abundance (ecology) education Ecology Evolution Behavior and Systematics Nature and Landscape Conservation media_common |
| Zdroj: | Biological Conservation. 51:113-123 |
| ISSN: | 0006-3207 |
| DOI: | 10.1016/0006-3207(90)90106-y |
| Popis: | The smooth-billed ani Crotophaga ani (L.) was apparently brought to Santa Cruz Island, Galapagos from mainland Ecuador by farmers hoping to alleviate tick problems on their cattle. Anis first appeared in the early 1960s but were not reported again until the late 1970s. After heavy rainfall during the 1982–1983 El Nino event, the ani population increased rapidly to an estimated 800 birds on Santa Cruz and the birds invaded other islands. Anis were known to be breeding only on Santa Cruz and probably Isabela during our census in 1986; however, other islands have been invaded recently and several of these are likely to provide suitable habitat. We estimated 4800 anis in the farm zone of Santa Cruz, where the population density was greatest. On Isabela we estimated there were approximately 100 birds, primarily in the farm zone. Principal food items in the diet were grasshoppers (Orthoptera), caterpillars (Lepidoptera) and spiders (Araneae). Their diet overlaps with native bird species. Potential threats to the Galapagos ecosystem include competition with the native bird fauna, seed dispersal of introduced plants and introduction of avian diseases. We recommend that the ani be eliminated from the Galapagos Islands. |
| Databáze: | OpenAIRE |
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