Brightsmilh and Villalobos • CLAY LICK FEEDING STRATEGIES OF PARROTS 
597 
TABLE 2. Weights for the five principal components which explain the most variance in group composition of 
psittacines at an avian geophagy site in southeastern Peru. All principal components have eigenvalues >1. Each principal 
component is identified with a text label which describes the bird aggregation it represents. The most abundant species in 
each aggregation are shown in bold. 
PCI 
PC II 
PC III 
PC IV 
PC V 
Species 
Large parrol 
Large macaw 
Parakeet 1 
Parakeet 2 
Parakeet 3 
Red-and-green Macaw 
0.09 
0.56 
-0.03 
0.09 
0.12 
Biue-and-yellow Macaw 
0.18 
0.47 
0.04 
-0.01 
0.00 
Scarlet Macaw 
0.17 
0.54 
0.11 
0.03 
0.03 
Chesinui-fronted Macaw 
0.55 
-0.09 
-0.08 
0.16 
0.12 
Red-bellied Macaw 
0.45 
-0.15 
-0.08 
0.22 
0.21 
Mealy Amazon 
0.51 
-0.20 
-0.04 
0.10 
-0.05 
Yellow-crowned Amazon 
0.15 
-0.13 
0.17 
-0.14 
-0.69 
Blue-headed Parrot 
0.21 
0.13 
0.53 
-0.14 
-0.34 
Orange-cheeked Parrot 
-0.03 
-0.12 
0.66 
-0.15 
0.31 
White-eyed Parakeet 
0.23 
-0.22 
0.08 
-0.27 
0.21 
Dusky-headed Parakeet 
-0.15 
-0.10 
0.42 
0.43 
031 
White-bellied Parrot 
-0.16 
-0.07 
-0.04 
0.49 
-0.22 
Blue-headed Macaw 
-0.01 
0.02 
0.16 
0.59 
-0.22 
Percent variance explained 
18 
14 
10 
9 
8 
principal components represent three mixed 
species aggregations which use the lick as distinct 
entities. The large parrot aggregation was com¬ 
posed of three abundant species: Chestnut-fronted 
Macaws ( Ara severus ), Mealy Amazons (Ama- 
zomfarinosa ), and Red-bellied Macaws ( Orlhop- 
siuaca mnilata). These were regularly joined by 
up to seven additional species: White-eyed 
Parakeet ( Aratinga leucophthalma). Yellow- 
crowned Amazon (Amazona ochrocephala ), 
Blue-headed Parrot ( P ion us menstruus), Blue- 
and-yellow Macaw ( Ara a rare/unit), Scarlet Ma¬ 
caw (A. macao). Red-and-green Macaw (A. 
chloropterus), and Orange-cheeked Parrot ( Pyr- 
ilia barrabandi). This aggregation, represented by 
PC I. accounts for 18% of the variance in lick use. 
Tile large macaw aggregations contained three 
common species: Red-and-green Macaws, Scarlet 
Macaws, and Blue-and-yellow Macaws (PC II, 
of the variance) which were rarely joined by 
Blue-headed Parrots, Mealy Amazons. White- 
eyed Parakeets, and Chestnut-fronted Macaws. 
The principal components analysis identified 
three parakeet and small parrot aggregations, 
°ne with Dusky-headed parakeets ( Aratinga 
*»eddellii ), Orange-cheeked Parrots, and Blue- 
headed Parrots (PC III, 9% of the variance), one 
with White-bellied Parrots ( Pionites leucogaster). 
Blue-headed Macaws (Primolius couloni), and 
Dusky-headed Parakeets (PC IV, 9% of the 
variance), and one with Dusky-headed Parakeets. 
Orange-cheeked Parrots, and White-eyed Parakeets 
(PC V. 8% of the variance). These three groups 
were functionally similar: both formed around 
flocks of Dusky-headed Parakeets or occasionally 
White-eyed Parakeets and used the same part of the 
lick. Thus, these groups were considered collec¬ 
tively as the ‘parakeet aggregation’. 
Ten species were recorded using the lick in 
monospecific groups, but most were monospecific 
remnants of the mixed species aggregations. Only 
three species regularly used the lick in coherent 
monospecific groups: White-eyed Parakeets, 
Dusky-headed Parakeets, and White-bellied Par¬ 
rots (Table 2). Single psittacines were recorded on 
the lick 58 times and these birds were often 
leading larger groups of birds to the lick (36%) or 
remained when larger groups abandoned the lick 
(31%) leaving only 19 instances of single birds 
using the lick. 
We focused on the three mixed-species aggre¬ 
gations as they accounted for >90% of the clay 
lick use. The three mixed-species aggregations 
were independent, as they arrived, staged, and 
descended to the lick separately, and used 
different areas of the lick. They also rarely reacted 
to each other’s alarm calls. The behavior of the 
birds at clay licks can be divided into three 
distinct phases: arrival in the area, descent to the 
lick, and lick use. 
Arrival in the Area .—All birds arrived in 
monospecific flocks. Multiple species, when seen 
together, did not perch or stage together indicating 
they were just casual associations. Observers 
