ELEVATIONAL MIGRATIONS AND HABITAT LINKAGES: USING THE
RESPLENDENT QUETZAL AS AN INDICATOR FOR EVALUATING
THE DESIGN OF THE MONTEVERDE RESERVE COMPLEX
George V. N. Powell, Robin D, Bjork, Sergio Barrios, & Vicente Espinozahe migration of songbirds between their breed-
ing areas in the temperate zone and wintering
grounds in the neotropics illustrates the sea-
sonal dependencies of birds on ecosystems far re-
moved from each other. Many bird species also migrate
even though they never leave the tropics (Wheel-
wright 1983, Stiles 1985,1988, Levey 1988, Stiles and
Clark 1989, Loiselle and Blake 1991,1992, Levey and
Stiles 1992). These migrations complicate the task of
protecting biodiversity because they create complex
ecological linkages and interdependencies among
tropical habitats. Unless all habitats in the linkages
are maintained, species that depend on them are likely
to be extirpated from their entire range, even though
representative samples of all the habitats may be pro-
tected in scattered locations (Noss 1990).
Intratropical migrations in the Tilaran mountain
range must be a primary consideration in the design
of the Monteverde Reserve Complex (hereafter, the
preserve), the MCFP, and the International Children's
Rainforest. We monitored the seasonal movements of
the Resplendent Quetzal (Powell and Bjork, in press),
which was a principal symbol used to justify the pre-
serve's establishment. Our objective was to use the
quetzal as an indicator to evaluate the preserve's ca-
pacity to protect regional biodiversity. Quetzals had
been identified as elevational migrants (Wheelwright
1983, Loiselle et al. 1989), but the details of their mi-
grations were unknown.
We used radiotelemetry to track individuals of the
Monteverde quetzal population to elucidate their an-
nual life cycle. The birds were captured during the
breeding season at their nests or in feeding trees, and
tiny radio-transmitters weighing less than 6 g (3% of
a bird's body mass) were placed on them with har-
nesses in the form of a backpack. With the radio-
tagged birds, we were able to record individuals'
movements and habitat use precisely. Over a three-
year study period (1989-1991), we radio-tagged 21 in-
dividuals; four birds were recaptured once and two
were captured all three years, for a total of 29 trans-
mitters placed on birds. We documented a two-parted
seasonal migratory pattern that linked the quetzals to
habitats on both sides of the Continental Divide, from
1000 m on the Pacific slope to as low as 500 m on the
Atlantic slope (Powell and Bjork, in press).
In the Monteverde area, quetzals breed between
1500 and 1800 m primarily on the Pacific slopes and
within the preserve (Fig. 12.5). Their breeding season
lasts from mid-February until the end of July. With
the completion of breeding, the radio-tagged quetzals
move down the Pacific slope to elevations between
1000 and 1400 m. At this elevation, the birds occur
outside the protected area (Fig. 12.5), in small rem-
nants of forest on farms in Monteverde and nine
other rural communities. The landscape in this area
is dominated by cattle pastures, agriculture, and
other human development. The quetzals remain 3-
4 months (August-October) in the small forest frag-
ments. In October or November, they move back up
the slopes, across the Continental Divide and down
the Atlantic slope (Fig. 12.5) into forests between 500
and 1100 m. They remain in these Atlantic slope lo-
cations for 2-3 months (November into January) be-
fore returning to their breeding areas.
The greatest surprise of this study was the discov-
ery that most individuals migrated to both sides of the
mountains during the annual cycle. More than 80%
of the radio-tagged birds undertook the first phase of
the migration (down the Pacific slope) and more than
90% of the birds undertook the second phase (down
the Atlantic slope). Documenting this complex pat-
tern of movements in each of three years allowed us
to conclude that it was a consistent pattern.
To provide an index of habitat diversity in the areas
used by quetzals, we classified the middle elevation
communities in terms of the Holdridge life zone sys-
tem (Holdridge 1967, Bolafios and Watson 1993). We
identified which life zones were used by quetzals and
used a geographic information system (GIS) to ana-
lyze the extent of each life zone in the preserve.
There are five life zones (including one transi-
tional belt) in the Tilaran Mountains above the 500
m elevation that marks the lower limit of quetzal
migrations. The quetzal population breeds primarily
in the lower montane rain forest life zone, which is
well represented within the preserve with more than
6100 ha of habitat protected (Fig. 12.6). The pre-
montane rain forest life zone on the Atlantic slopes,
used by quetzals during the second part of their an-
nual migration, is also well represented in the pre-
serve (Fig. 12.6). Recent expansion of the preserve
(the International Children's Rain Forest) and cre-
ation of Arenal National Park in the northern part
of the Tilaran Mountains protect much of the pre-
montane rain forest habitat in that area. However, the439 Conservation BiologyT