Monitoring Bird Diversity at El Edén Ecological Reserve, Quintana Roo

Tom Will

Gettysburg College
Dept. of Biology
Box 392
Gettysburg PA 17325 USA
tel: (717) 337-6167
fax: (717) 337-6157

In October of 1995, I began preliminary investigations at El Edén to establish and verify a definitive bird species list for the reserve and to lay the groundwork for a long-term bird diversity, population monitoring, and longevity study. In July 1996, I returned to the reserve for a few days to continue work on this project. My results to date are based on those two visits, a total of about 10 days in the field.

Assisted by the Souhegan (New Hampshire) High School BioSwat Team, Jared Wilson and I conducted a rapid survey of the avifauna of Reserva Ecolgica El Edén on 21-26 October 1995. Despite adverse weather and meter-deep inundation of savanna and tintal habitats resulting from hurricanes Opal and Roxanne, we managed to record a total of 128 definitively identified bird species, 44 of which were new additions to the evolving El Edén list begun by Hernandez et al. (1995).

We mist-netted birds on three mornings in two locations: along a trail in medium-height semideciduous tropical forest west of the station and in an area of disturbed scrub and low secondary forest east of the station. We captured a total of 119 individuals of 39 species, and 102 of these were ringed with uniquely numbered metal leg bands. More than half of these (55%) were long-distance nearctic migrants originating in North America. We caught four times as many birds per net-hour Data, summarized results, and a brief discussion are available in Will and Wilson (1995).

My work in July 1996 was conducted in association with the establishment of permanent biodiversity sampling plots under the HabitatNet program coordinated by Dan Bisaccio. The HabitatNet team members and I definitively identified 87 bird species, 9 of which were new to the El Edén list. No nearctic migrants were present. We mist-netted birds in the same two locations used in October 1995 and captured 44 individuals of 21 species, 30 of which were newly banded. We recaptured four individuals which had been banded the previous year. Once again, we captured more than twice as many individuals per net-hour in the disturbed scrub habitat than we did in the forest.

I plan to continue making visits to El Edén to observe and capture birds in the same locations. The mist-netting component can easily be coupled with other workshops as a demonstration of biodiversity sampling technique. In addition, I would be happy to cooperate with other ornithologists or students in the development of a more intensive bird monitoring project. Specific objectives might include:

* long term migrant and resident bird monitoring (as part of a program for biodiversity monitoring and conservation in the region);

* quantitative determination of specific habitat configurations used by migratory birds;

* a study of changes in physiological condition of residents, transients, and resident migrants at El Edén;

* resolution of the local variation, introgression, and systematics of Arremonops rufivirgatus and A. chloronotus;

* long-term population dynamics of selected species in different habitats based on capture/recapture methods.

Literature Cited
Hernandez, M.A., E. Ruelas, E. Iigo E., B. M. de Montes, y M.A. Lazcano-Barrero. 1995. Lista preliminar de aves registradas en La Reserva Ecolgica El Edén. Reserva A.C.
Will, T. and J. Wilson. 1995. A rapid assessment of the birds of Reserva Ecolgica El Edén, Quintana Roo. Informe to La Reserva El Edén. El Colegio de La Frontera Sur, San Cristbal de Las Casas, Chiapas, México.