The Wilson Journal of Ornithology 123(3):502-507, 2011 
NESTING SUCCESS OF NEOTROPICAL THRUSHES IN COFFEE 
AND PASTURE 
CATHERINE A. LINDELL, 12 J RYAN S. O’CONNOR. 1 "' AND EMILY B. COHEN 14 * 
ABSTRACT.—We monitored nesting attempts of White-throated (Turdus assimilis) and Clay-colored thrushes (T. grayi) 
over 4 years in southern Costa Rica to compare nest success in recently abandoned coffee (Coffea spp.) plantations, pasture, 
and along roads. Daily mortality rates of Clay-colored Thrush nests were lower in pasture (0.054 ± 0.014) than abandoned 
coffee plantations (0.096 ± 0.012). Daily mortality rates of White-throated Thrush nests were not influenced bv land-cover 
type but were lower at highly concealed nests (0.058 ± 0.005) compared to less concealed nests (0.090 ± 0.017). and at 
nests that were on the ground (0.0580 ± 0.005) versus in vegetation (0.076 ± 0.007 ). Daily mortality rates for nests of both 
species were very low at an active coffee plantation where nests were monitored in I year (0.006 ± 0.004 and 0.015 r 
0.015, for White-throated and Clay-colored thrushes, respectively). Nests at the active plantation were heavily concealed 
which, along with results for White-throated Thrushes in abandoned coffee, indicates concealment has a strong influence on 
tropical thrush nest success. Nest success appears to be heavily dependent on factors that may influence both concealment 
and or habitat lor predators. Nest success also appears to be strongly site-specific, making it difficult to provide general 
statements about the conservation value of different land-cover types. Received 22 September 2010. Accepted 9 Febniarx 
An estimated 50% of what was once tropical 
forest has been cleared (Wright 2005). The 
agricultural land-cover types that replace tropical 
forest will influence future population sizes and 
fates of numerous species (Vandermeer and 
Perfecto 2007). Some land-cover types are 
considered of greater conservation value than 
others, usually on the basis of relative abundance 
and or presence/absence data (e.g., Sodhi et al. 
2005). For example, more bird species have been 
detected in rustic coffee (Coffea spp.) plantations 
(those with shade trees) than pastures (Petit and 
Petit 2003, Estrada and Coates-Estrada 2005). 
suggesting that coffee plantations are of higher 
conservation value. 
Successful nesting is arguably a much more 
important indicator of conservation value than 
presence of a species in a land-cover type, but 
information on reproductive success of tropical 
birds in different land covers is sparse (e.g., Gleffe 
et al. 2006, Sekercioglu et al. 2007). Coffee and 
pasture cover vast areas of the Neotropics (Fearn- 
side 1993, Rice and Ward 1996), but no studies 
have quantitatively compared nest success in 
coffee and pasture. 
' Department of Zoology, Michigan State University, 
East Lansing. MI 48824, USA. 
2 Center for Global Change and Earth Observations, 
Michigan State University, East Lansing. MI 48824, USA. 
Department of Biological Sciences, Eastern Kentucky 
University, Richmond. KY 40475, USA 
„ 4 2 epar :r nt of . Biological Sciences, University of 
outhern Mississippi, Hattiesburg, MS 39406. USA. 
Corresponding author; e-mail: lindellc@msu.edu 
Clay-colored Thrushes (Turdus grayi) tend to 
use open habitats such as gardens and pastures 
with some trees, although they also use forest 
during the non-nesting season. Bulky, cup nests 
are built on and above the ground in locations 
hidden by foliage or in banks (Stiles and Skutch 
1989, Lindell and Smith 2003). White-throated 
Thrushes (T. assimilis) forage and nest in both 
forest and non-forest habitats, on and above the 
ground (Cohen and Lindell 2004. Sekercioglu et 
al. 2007). Despite their apparent ability to use 
non-forest land-cover types, regional forest cover 
loss in Costa Rica in the last century may have 
contributed to a reduced country-wide distribution 
of the White-throated Thrush (Stiles and Skutch 
1989, Cohen and Lindell 2005). Their nests are 
similar in structure to those of the Clay-colored 
Thrush. 
Previous work suggested higher daily mortality 
rates for nests ot Clay-colored and White-throated 
thrushes in coffee compared to pasture (Lindell 
and Smith 2003), although sample sizes were 
small. Thus, based on nest success, coffee 
plantations may be of lower value than pastures 
for these species. 
Our First objective was to test the prediction 
that nest success of Clay-colored and White- 
throated thrushes would be greater in pasture than 
coffee. We discovered during field work that both 
species also nested in road banks and included 
road banks as a third land-cover type. A few 
White-throated Thrush nests were found in forest 
fragments and this was a fourth land-cover type 
for this species. Our second objective was to 
502 
