by ornithologists. In this chapter, we summarize stud-
ies on Monteverde's birds, describing areas that have
been well covered and identifying areas for future
investigation. We generalize to the bird community
as a whole based on (1) published data on a few spe-
cies, (2) information that was collected elsewhere on
species that occur at Monteverde, and (3) our own and
colleagues' observations.
MethodsWe define Monteverde as an area bounded roughly by
the village of Santa Elena to the north, Poco Sol on
the east, the southern limit of the Brillante trail of the
Monteverde Cloud Forest Preserve (MCFP) to the
south, and the village of San Luis to the west (Figs. 1.4,
1.6). Our definition of Monteverde encompasses an
area of about 20,000 ha and includes six Holdridge life
zones (Table 3.1). We refer to animals' common names;
scientific names are listed in Appendixes 9 and 10.
6.1. Distribution, Species Richness,
and Diversity
Monteverde's avifauna is derived from three princi-
pal regions: (1) the "Guanacaste" fauna on the Pacific
slope, which represents the southernmost extent of
the Mesoamerican dry forest fauna; (2) the highland
fauna, a distinct group of species that occurs in the
Costa Rican and Chiriqui, Panama, highlands; and (3)
the wet forest fauna of the Caribbean slope. The wet
forest fauna is derived primarily from South Ameri-
can groups; the highland and Guanacaste fauna are
a mixture of North and South American groups. Al-
though most areas of Costa Rica have either a dry
or wet forest fauna plus North American migrants,
Monteverde has all three because it straddles the Con-
tinental Divide. More extensive reviews of the zooge-
ography of Costa Rican and Central American avifau-
nas are available elsewhere (Howell 1969, Stiles 1983).
6.1.1. Life Zone Distribution
Monteverde's geography and climate, with a steep dry
season gradient of increasing moisture from Pacific
to Caribbean slope, create remarkably distinct vegeta-
tion in the different life zones (Table 3.1). Avian spe-
cies richness also varies across the life zones (Table
6.2). Zone 4 (lower montane rain forest) has the low-
est species richness (121 regularly occurring species),
perhaps because of its small geographical extent and
isolation from the more diverse high elevation faunas
of the Central and Talamanca Cordilleras to the south.
Zone 4 also has the highest proportion of unique
species (9%).
Zones 5 and 6 (premontane rain and tropical wet
forests) on the Caribbean slope (315 and 278 species,
respectively) are the most species-rich life zones.
These middle-elevation zones approach the highest
bird species diversity of any site in Costa Rica, ri-
valing well-studied La Selva Biological Station with
256 breeding species and 155 migrants and rare visi-
tors (Levey and Stiles 1994). Life Zones 5 and 6
are low enough in elevation to include the upper
limit of the ranges of many lowland species and
support many high-elevation species as seasonal
migrants. Zone 6 includes a 2-ha lake and adjacent
wetland that attract water birds not seen elsewhere
in Monteverde.
Another method to characterize diversity (besides
tallying species) is the species accumulation curve.
The rate of accumulation of species is plotted as a
function of the number of mist-net captures (Karr et al.
1990a). Although canopy species are underrepre-
sented and forests of different statures are not com-
parable, the data are useful indicators of diversity.
Species accumulation curves based on captures in
second-growth and old-growth forest indicate that the
Caribbean slope site (Zone 6) is much more diverse
than the Pacific slope site (Zone 2; Fig. 6.3). The spe-
cies accumulation curves for Zone 6 are so steep that
even after several hundred captures, there is no indi-Table 6.2. Patterns of bird diversity in the six principal life zones of Monteverde.
Pacific Slope Continental Divide Caribbean SlopeZone (^1) Zone 2 Zone 3 Zone 4 Zone 5 Zone 6
Life zone
Species richness
Cumulative species
Unique species
Lower
Premontane Premontane montane
moist wet wet
Lower
montane Premontane Tropical
rain rain wet
165
165
202
219
6
187
265
0
121
274
11
315
394
17
278
425
Numbers of unique species for Zones 1 and 6 were not calculated due to a lack of information on birds from the adjacent zones downslope.
Species listed as accidental or uncertain in Fogden (1993) are not included (see Appendix 9). See Table 3.1 for elevational ranges of zones.
182 Birds