Written by Hernan Vargas, 1999
Head Ornithlogist
Charles Darwin Research Station
BACKGROUND
The Galapagos Islands have an extraordinary avifauna. Most famous, of course, are the finches, which inspired Darwin to develop his theory of evolution by natural selection. No less than 85% of the land birds are endemic to the archipelago, and several of these are endemic to a single island within the archipelago. In addition, the seabirds include endemic species such as the Galapagos penguin, flightless cormorant and the elegant swallow-tailed gull. Given their limited range, it is not surprising that the populations of some of the Galapagos species have always been small. For example mangrove finches and lava gulls have populations of less than 1000 individuals. The endemic birds of Galapagos, therefore, need careful conservation, as small populations are especially vulnerable to such threats as the loss of habitat, the increasingly frequent fluctuations in local climate, and the introduction to Galapagos of predators, competitors and new diseases.
The Charles Darwin Research Station (CDRS) and the Galapagos National Park Service (GNPS) work together for the conservation of the archipelago, with the Station providing scientific and technical guidance to the park managers. Ornithology has been a component of the CDRS program since its inception in 1964. Unfortunately, there was a lull in ornithological work during the early 1990's, when the Station had no resident ornithologist. Since 1995, however, the program has seen a major revival, with the implementation of the following activities:
Searches for more populations of mangrove finch on Isabela and Fernandina.
Studies of the mangrove finch breeding biology and genetics.
Organization and analysis of banding data (mainly albatross and dark-rumped petrels).
Revision of museum avian specimens and establishment of a database.
Establishment of an avifauna data bank.
Advising the Galapagos National Park Service on management practices to protect threatened species.
Establishment of a system for avian data collection.
Environmental education to promote conservation of threatened bird species.
Collaboration with visiting scientists regarding ornithological research.
Conservation success stories in Galapagos include the dark-rumped petrel, an endemic ground-nesting sea bird, now breeding successfully and increasing in numbers, thanks to control of the introduced black rats that preyed on eggs and chicks. The penguins and cormorant populations also seem to be stabilized, the numbers at 933 and 1088, respectively, according to the latest surveys by the CDRS and GNPS. This is in spite of increased fishing and other human activity around their habitat in the western part of the archipelago.
On the other hand, the surveys of land birds have revealed some serious problems, especially on the five inhabited islands of the archipelago. Surveys of mangrove finch populations, always the rarest of Darwin's finches, found fewer than 40 pairs. In 1996, on San Cristobal Island, we found no evidence of the vermilion flycatcher (endemic subspecies restricted to that island), very few sightings of the Galapagos rail and Galapagos dove. The reasons for these declines are not known, but there is no shortage of possible causes: introduced cats and rats have proliferated on some islands; invasive introduced plants are transforming some habitats; an introduced wasp may be competing with the mangrove finch for food; and there have been examples of introduced diseases, e.g. pox, New Castle and Marek's, that may be affecting the endemic avifauna.
Meanwhile, the species already introduced pose a serious threat to the endemic birds of Galapagos, and there is an urgent need for research, monitoring and conservation action to protect them. That is what this program is all about. The CDRS and the GNPS have identified priorities and are appealing to bird enthusiasts worldwide to support our efforts.
THE PROGRAM OF PRIORITY ACTIVITIES 1999
The three-year program is composed of seven important projects, each with priority activities. One represents the core support needed to keep the ornithological program in existence. Two address urgent conservation needs: studies of avian diseases and the conservation of the mangrove finch, two other projects are the studies of threatened birds such as the Galapagos rail and the land birds of San Cristobal Island. A sixth project monitors vulnerable species: the penguin, cormorant and flamingo, and the seventh project consolidates the successful recovery of a species: the dark-rumped petrel. Every project in the list concerns mainly species found only in the Galapagos Islands.
The priorities for funding of these activities have been based on the fact that major threats for the Galapagos avifauna are currently introduced diseases and parasites such as the Philornis, which is affecting several species of the endemic finches, the conservation of the Galapagos rail seriously affected by habitat change and fragmentation and the conservation of the mangrove finch that will help us understand the effects of potential introduced predators (black rats) on the rarest of Darwin's Finches.
Written By: Hernan Vargas, Head Ornithologist, CDRS