Expedition 2000 to Isla
Because of the lack of water and the difficulty in accessing the island's rugged terrain, a helicopter is an essential transportation vehicle for this exploration. A boat capable of transporting a helicopter is thus needed. We have located a utility boat, with helicopter capability, that can accommodate a dozen researchers. Equipment and supplies necessary for this trip include camping and emergency equipment (especially fresh water), communications equipment such as Global Positioning System, cameras and film, compasses, VHF radio, etc.
Two independent survey teams (seabirds and land birds) will be deployed at Isla Guadalupe to provide the fullest possible coverage of the bird life. For safety, each team will have a minimum of two persons. Depending on weather and other factors, surveyors will cover the maximum area during their time on the island. We anticipate that the allotted time, barring extreme bad weather, will be sufficient to determine the status of all species of interest to the two teams. While it is not our goal to collect bird specimens, any non-breeding vagrants or mist-net casualties will be collected. Also, any carcasses or identifiable bones found will be recovered, as will feathers. Specimens will be deposited in collections of both the Museum and CICESE. The teams and methods they will employ are as follows:
The primary objective of the seabird team will be to determine if the Guadalupe Storm-Petrel (Oceanodroma macrodactyla) has escaped extinction. This species has never been found away from its breeding colonies, the forests of pine and cypress at the highest elevations of this island. Using the project's helicopter, equipment, water, supplies, and team members will be flown to the high altitude forests to establish a base camp, which will remain functional for three to five days and nights. During the daytime, the forest will be carefully searched for nest sites reported to be among the roots of the trees or in rock crevices. Any potential nest sites will be visually examined, and checked for the distinctive, pungent odor conspicuous at all storm-petrel nest sites. If occupied sites are found, birds will be captured, measured, photographed and released to confirm species identification. Global Positioning System (GPS) data will be recorded and the site and vicinity photographed as additional documentation.
At night, a series of mist nets will be deployed and monitored at appropriate locations within the forests to capture any birds that might be flying through the area. Any captured birds will be measured, photographed and released to confirm species identification. Locations of nets will be recorded with GPS equipment. All pertinent aspects of capture effort will be recorded, including size and denier of nets, weather conditions, terrain aspect and habitat composition.
Away from the forest areas, seabird team members will examine areas on the main island that appear suitable for occupation by any seabird species. Careful ground searches will reveal presence of any nocturnal or underground nesting species. On offshore rocks, all reachable areas will be carefully searched, and search details recorded, to establish precisely which species use the habitat, and in what numbers they occur.
Land Bird Team
A separate team dedicated to assessing the status of land birds on Isla Guadalupe will focus first on endemic species and subspecies, to establish and document current population status and distribution. This team will also begin its work in the forests of cypress and pine. Visual and aural searching will be the main survey method employed, and as appropriate, mist nets may be used to capture land birds during the daytime as necessary to determine species or subspecies. Any birds captured will be subsequently released. As with the seabird capture effort, all parameters of survey effort will be recorded and documented.
Since land birds are expected to be found in the most densely vegetated areas of Isla Guadalupe, land bird surveyors will select additional areas for examination that show promise, especially for endemic or insular forms. As appropriate, point or strip census techniques will be used. However, since uniform and equal distribution of any bird species at Guadalupe is unlikely, systematic sampling to statistically establish population estimates will not be used. These techniques are more likely to result in misleading or incorrect estimates than intuitive interpretation of direct observations.