Brightsmith and Villalobos • CLAY LICK FEEDING STRATEGIES OF PARROTS 
601 
However, there is evidence that group composi¬ 
tion, relative abundance, and timing of lick use 
van' among sites (Mee et al. 2005) suggesting 
birds may be responding to a variety of undoc¬ 
umented site-specific circumstances. Comparative 
studies would be highly informative. 
Only three of 13 parrot species used the clay lick 
in cohesive monospecific groups: White-eyed 
Parakeet, Dusky-headed Parakeet, and White- 
bellied Parrot. These species, when not using the 
clay lick, normally occur in the largest monospe¬ 
cific groups of the 13 species (Gilardi and Munn 
1998, Table 3). Other psittacines in the region, 
Cobalt-winged Parakeets (Brotogeris cyanoptera). 
Rose-fronted Parakeets ( Pyrrhura roseifrons). 
Black-capped Parakeets (P. rupicola ), and Dusky- 
billed Parrotlets (Forpus modestus) also occur in 
large groups away from clay licks and initiate lick 
use in monospecific groups (Gilardi and Munn 
1998; DJB, unpubl. data). These findings suggest 
there is a causal link between species' intraspecific 
sociality and monospecific lick use. 
Arrived and Descent to the Lick .—Animals 
approaching geophagy sites are normally wary 
Ozawa 1993). The two approach behaviors we 
documented, slow circular flights and moving 
deliberately through adjacent trees likely serve to 
(1) check the lick area for predators, (2) watch for 
landslides, and (3) recruit individuals to the lead 
group. Birds would break-off their approach or 
shift to alternative areas of the lick when predators 
or landslides were detected. Parrots would also 
break off their approach if the first group was not 
joined by others. 
Spatial Distribution .—Bird use was confined to 
lour small areas of the cliff even though the soil 
was useable across the majority of the lick (DJB, 
unpubl. data). This suggests the pressure to 
congregate (as protection from predators) is 
stronger than the pressure to disperse across the 
lick (likely due to competition). The large macaws 
used the highest and most open areas of the clay 
lick most frequently while the smallest species 
used the areas closest to cover. This is similar to 
findings from previous studies (Burger and Goch- 
feld 2003, Mee et al. 2005). Why lick site selection 
varies with body size is unknown, but likely relates 
to methods of approaching the lick and avoiding 
Predators displayed by the different species. 
ACKNOWLEDGMENTS 
The staff of Rainforest Expeditions and Tambopata 
Research Center provided logistical support for this research. 
Thanks to Kurt Holle and all volunteers that collected the 
data for this study especially the project field leaders: Robert 
Wilkerson. Mark Dragicwiez, Oscar Gonzalez. Adriana 
Bravo, Aida Figari, Daphne Matsufuji. Kurina Quinteros, 
and Gabriela Vigo. Thanks also to Lizzie Ortiz Cam. We also 
thank the offices of the Institute Nacional de Recursos 
Naturales (INRENA) and the Tambopata National Reserve 
for permission to conduct this research. This work was 
funded by Earthwatch Institute, Rainforest Expeditions, 
Raleigh-Durham Cage Bird Society, Willard and Lucille 
Smith, Amigos de las Aves IJSA. and other private donors. 
The manuscript was improved by comments from Alan T. K. 
Lee, Gabriela Vigo, and two anonymous reviewers. Facilities 
during manuscript preparation were provided by the Schubot 
Exotic Bird Health Center at Texas A&M University. 
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