The camera traps were placed with the primary intention of maximizing tiger captures and

were set along routes where there was tiger sign scatss, scrapes, scent deposits, tracks) and at the

intersection of well-used trails. The spacing between camera traps ranged from 1-2 km. All

points were marked on maps using a GPS unit. The date, time, and location of all animal

captures were noted (Figure 3-2).

 Data were collected from the two parks from December until May in 2003-2004 and 2004-

2005. Sampling was done at 120 camera-trap locations in Nagarahole and 118 camera-trap

locations in Bandipur. Since it was logistically impractical to conduct sampling at all these

camera trap locations simultaneously, the trap points were divided into blocks of 40 trap points

each. After sampling for 10-15 nights in one block, the camera traps were moved to the next

block and sampling would continue 10-15 nights. In total, the study area consisted of 6 blocks.

Logistics, weather and budget constraints limited the number of consecutive nights the cameras

were deployed at a trap site (Table 3-1).

Application of the Royle and Nichols (2003) Model

Definition of sites

 Occupancy surveys that are described in MacKenzie et al. (2002) and Royle & Nichols

(2003) use sample units as "sites". Implicitly, it is assumed that each site is independent and no

animal will move between sites during the survey period. Unless the movement of animals is

very small compared to the selected cell size, setting up a grid system and using these models for

adjacent cells will violate the assumption of independence between sites. Thus, using these

models for a species that ranges widely, like the sloth bear (Garshelis et al., 1999), will generate

results that require an alternative interpretation. To minimize the size of sites based on different

possibilities of home range size and to maintain the assumption of independence of abundance

between sites, I selected sites from the study areas in Bandipur and Nagarahole National Parks