2. METHODS
2.1 The study area
The study area, Chinnar Wildlife Sanctuary, is located between 10°15’-
10°21’N latitude and 77°16’- 77°5’ E longitudes in the Idukki district
of Kerala state (Figure 1) and has a total extent of 90.44
km2. The significant variation in altitude and
rainfall leads to a wide array of habitat types like deciduous forests,
dry thorny scrub, riparian forests, shola forests and grasslands that
are interspersed with plains, hillocks, rocks and cliffs, which provide
microhabitats for varied forms of life (Management Plan of Chinnar
Wildlife Sanctuary., 2012).
2.2 Observation methods
The information on the composition and seasonal variation in the GGS
diet was collected through foraging observations. Focal Animal Sampling
was used following (Altmann, 1974). Each encountered individual was
followed, and observation on the time spent on feeding, plant species
eaten, plant part eaten, pick up rates of plant parts such as fruit,
leaves and flowers were also recorded. The activities occur in bouts
that are periods of, for example, feeding activity within a food source
or movement between two sources. During the period spent in the food
source, some of the time was allotted to searching for a food item,
selecting by smelling, remaining inactive or other grooming activities.
The length of the bout was judged as the period between entry into and
exit from the source. The incidence of feeding on different food items
across different seasons was categorised. This was done for the three
different seasons summer (December to May), southwest monsoon (June to
September) and northeast monsoon (October to November).
Observations were made for 10 months between April 2013 to May 2014, and
within a month, at least one week was spent in the field. Five transects
were selected after reconnaissance, and observations were made for each
transect both in the forenoon and afternoon for an equal duration.
Squirrels were observed using 8x40 Olympus standard binoculars (Olympus
Global, Tokyo, Japan). Different feeding postures and feeding techniques
used by the GGS were interpreted by direct observation during the
sampling.
2.3 Data analysis
To understand the food composition of GGS, collected data were analysed
by three complementary approaches. The percentage contribution of
different food items to the squirrel diet was analysed based on the
duration of feeding on a particular item and the number of times of
feeding incidence on a particular item. The non-parametric test, “Mann
Whitney U” was performed to determine whether there was any significant
difference in the feeding bout and duration between the forenoon and
afternoon hours. ᵡ2 test for
association was used to find out the seasonal variation on the preferred
tree species and the plant parts fed by the GGS across different
seasons. A constrained analysis, species as response variable
against the environmental variables (Residualized predictors were
permuted), canonical correspondence analysis (CCA) was performed to
check the food choice and season using Canoco 5 (Braak & Smilauer,
2012; Jiangshan et al., 2014).