Abstract-Two coffee plantations (one shade and the other sun) studied had similar abundance and species diversity. However, the time/species curve may indicate that the peak of diversity was not reached in either site so nothing can be determined about the actual diversity at either site. The study did indicate that the types of species present were different. This study should be conducted over a longer period of time before a more definitive statement can be made about species richness in the two sited (as based upon the saturation of the time/species curve).

Introduction - Traditionally, coffee is grown under a canopy of shade trees. These shade coffee plantations have a relatively high biodiversity due to the structural and floristic complexity of the shade trees. Coffee plantations are increasingly being transformed into industrial plantations with little or no shade (Perfecto et. al. 1995). This may result in a loss of biodiversity among animals (including birds) that would normally be found on shade coffee plantations. "The Pacific slope of the central cordillera in Central America has been particularity devastated. Where deforestation is high and coffee is still produced on traditional shade plantations, these plantations are likely to be a critical refuge for the forest biota". (Perfecto et. al. 1996). Costa Rica is losing a lot of forestland as it is being converted into farmland. However, "tropical forest clearings are rarely complete and often not permanent, thus creating forest patches. Forest patches can provide additional habitat for many species. Patches offer diverse forest for use, ecological niches for species, ecological services such as fertility restoration, watershed protection, harboring pollinators or predators of agricultural pests…. Even very small patches of isolated trees will attract birds. (Schlehas and Greenberg, 1993). "Fragmentation is a particular problem for neotropical migrants because of their nesting habits. Most neotropical migrants build open, cup-shaped nests that are relatively easy for predators to spot. They also tend to lay only a few eggs each year and may nest on the ground making them susceptible to predation. (Bonney et al.1995). Shade coffee plantations could serve as corridors between patches of forest which facilitate the movement of animals. They may also provide protection from predators and supply feeding and nesting sites. During migration, birds use a large array of habitats including tropical rainforest. "Neotropical migrants funnel through small areas where they rest and feed before beginning nonstop flights over land or water. Many species make 20 –, 40 -, and even 80 – hour non-stop flights over water, so coastal habitats are particularly important stopover zones. Unfortunately, these areas are disappearing. Shade coffee plantations may help substitute this loss of tropical forest and provide a safe haven and rest area for these migrant birds.

This paper is not intended to be a detailed research paper. It is based on a two-day comparative survey of the bio-diversity of birds in a shade coffee plantation vs. birds in a sun coffee plantation. The hypothesis is that the shade coffee plantation will demonstrate a greater diversity in bird species and also contain a greater number of birds than the sun coffee plantation. It has been suggested "that all taxa of birds be a measure of biodiversity of tropical forests" (Castri, et.al. 1992). In our study we measured the biodiversity by recording the total number of birds and different species at the two sites.

Site - Two sites were selected based on proximity to each other (within 0.5km) while differing in both the diversity and abundance of companion plants. Both sites were less than 2 ha in area. The shade coffee farm was on a ridge bordered on the south and west side by the Las Cruces Biological . The companion plants were dominantly banana to the east and corn to the west and several large trees dispersed throughout the field. These other trees included an orange tree, Cecropia, and…The coffee plants themselves were probably about 10 years old. The sun coffee farm was in a valley bordered to the North by small woods, to the East by a banana farm and on the other two sides sun coffee plants. These coffee plants were 25 years old. The only companion plants were occasional rows of ornamental corn.

Method - Two mist nets, 20 meters in length by 2.5 meters high, were used for each site. At the shade coffee site, net 1 ran east to west bordering the edge of the coffee rows and net 2 ran north to south in 3 meters into the field and was set 4 meter west of net 1. At the sun coffee site, net 1 was set in the middle of the field with net 2 10 meters away set in between dense rows of coffee. At least two observers operated each array. Birds caught in nets were removed, species identified and sexed (table #1). We operated the net arrays for 15 and 16 hours each (table #2). They show the same total number of birds captured while number of species was similar (14 and 17). When normalized to net hours, species diversity also becomes nearly the same (table #2, figure #1).

Results - Table #1 Species Captured

Conclusion - A similar abundance and species diversity was found at each site. The two sites did differ in species composition though. The sun plantation had a greater number and diversity of seed eating species, while the shade coffee plantation contained a greater number of hummingbird species. The latter observation is probably related to several adjacent flowering plants and orange tree near the array. It also appears from the time species curves (figure #2) that neither trapping effort resulted in species saturation. Thus the study is inconclusive as to the true abundance and diversity of the two sites. This makes it difficult to evaluate the difference between the two sites within the given time frame. It does seem that the difference between these two farms is not dramatic and that the reason sun or shade coffee is not making a difference. It probably depends on the size of this small farm. A small farm operation would have more corridors of trees bordering it than a large-scale plantation.