The Wilson Journal of Ornithology 123 ( 3 ): 595 - 602 , 2011 
PARROT BEHAVIOR AT A PERUVIAN CLAY LICK 
DONALD J. BRIGHTSMITH 1 ’ AND ETHEL M. VILLALOBOS 2 
.ABSTRACT—We documented the behavior of 13 parrot species at a geophagy site along the Tambopata River in 
southeastern Peru. These species use the lick in one or more multi-species aggregations composed predominantly of (1) large 
parrots and small macaws of lick use), (2) large macaws (5%), or (3) parakeets and small parrots (5%). Monospecific 
flocks accounted for only 8% of lick use and lone individuals < I % of lick use. The multi-species aggregations sorted by body 
size and were generally composed of species with similar coloration suggesting that group composition was driven by a mix ot 
a nr petition and predation. Three species regularly used the lick in monospecific groups and these had the largest group sizes 
away from the lick, suggestion a causal relationship between intraspecific sociality and lick use in monospecific groups, 
uroups were wary when approaching the lick, probably due to the risk from landslides and predators. We suggest that clay lick 
use strategies are molded by predation risk and competition acting on a suite of species with varying body size, coloration, ana 
gregariousness. Received 12 July 2 009. Accepted I March 2011. 
Geophagy, the intentional consumption of soil, 
has been documented for a wide range of mostly 
herbivorous mammals, reptiles, and birds (Sokol 
1971 , Klaus and Schmid 1998, Diamond et ft)- 
1999. Brightsmith 2004). Hundreds of birds (up to 
17 species) gather daily at river-edge ‘clay licks’ 
lo consume soil throughout the western Amazon 
Basin (Emmons and Stark 1979, Burger and 
Gochfcld 2003, Brightsmith 2004). The birds, 
mostly psittacines, apparently consume soil for its 
high concentration of sodium (Brightsmith and 
Aramburu 2004, Brightsmith et al. 2008), but may 
also receive protection from dietary toxins 
(Gilardi et al. 1999). Aggregations of birds which 
use clay licks vary greatly in species composition 
and patterns of lick use, and much of this variation 
remains unexplained (Burger and Gochfcld 2003, 
Brightsmith 2004, Brightsmith and Aramburti 
-004. Lee et al. 2009). 
Observations suggest the birds' behavior at clay 
licks has been molded by predation and competi¬ 
tion. hut few detailed studies have been conducted 
'Burger and Gochfeld 2003. Brightsmith 2004, 
Brightsmith and Aramburu 2004). Social forces 
such as infonnation exchange, search for mates, 
and parental care favor group formation (Ward and 
Zahavi 1973, Wright el al. 2003). However, there 
am many costs to group membership including 
competition for resources (Grand and Dill 1999, 
Krause and Ruxton 2002) and disease transmission 
Schubot Exotic Bird Health Center. Department of 
Veterinary Pathobiology, Texas A&M University. College 
Station, TX 77843. USA. 
Department of Plant and Environmental Protection 
Sciences, University of Hawaii at Manoa. Honolulu. HI 
%822. USA, 
Corresponding author; 
e-mail: dbrightsmith@cvm.tamu.edu 
(Hoare et al. 2000). Clay licks and other geophagy 
sites provide good opportunities to study mixed 
species aggregations. We studied the behavior of 
panels using a large clay lick along the upper 
Tambopata River in southeastern Peru in an effort 
to document lick use strategies for comparison with 
research at other sites in the region (Burger and 
Gochfeld 2003). 
METHODS 
Study Area .—Tambopata Research Center (13 
08' S. 69" 36' W) is in the Department of Madre 
de Dios in southeastern Peru in the Tambopata 
National Reserve (275.000 ha) near Bahuaja- 
Sonene National Park < 1,091,000 ha). The area is 
tropical moist forest near the boundary with 
subtropical wet forest. The elevation is 250 m 
asl with 3,200 mm of rain per year and a wet 
season from October to March (Tosi 1960, 
Brightsmith 2004). The area contains a mix of 
mature floodplain Forest, successional floodplain 
forest, Mauritia ftexuosa palm swamps, and 
upland forest (Foster el al. 1994). 
The clay lick studied was a 500-m long, 25-30 m 
high, cliff on the right bank (west side) of the upper 
Tambopata River. The lick was apparently formed 
by the river’s erosion of recently uplifted Tertiary 
age alluvial sediments (Rasanen and Salo 1990. 
Foster et al. 1994, Rasanen and Linna 1995). It 
consists of two large exposed areas -150 m in 
length on the south end and 200 m in length on the 
north end. The two are separated by a landslide ot 
— 150 m in width. The south end contains a clay 
layer — 15-17 m high, topped by a band of sand and 
cobble about 5 m thick. The north end has clay 
about 8 m high topped by 8 m of sand and cobble. 
The soils of the clay layer are rich in high cation 
exchange capacity clays with high sodium levels 
595 
