Wildlife detector dogs and camera traps: a comparison of techniques for detecting feral cats

Figures & data

Table 1. Detections of cats (Felis catus) by camera traps and wildlife detector dogs deployed for one search event (see text for definition) in each of nine search cells on Waitere Station (low predator density) and Toronui Station (high predator density), Hawke's Bay, New Zealand.

Search cell	Site	Cameras	Dogs	Dogs’ search time (minutes)
1	Waitere	0	1	14
2	Waitere	1 (1)	0	98
7	Waitere	0	0	140
8	Waitere	0	1	17
9	Waitere	0	1	17
3	Toronui	0	0	112
4	Toronui	1 (2)	1	25
5	Toronui	1 (1)	1	9
6	Toronui	1 (3)	0	109
Total		4	5	541

Note: (1 = cat detected; 0 = no cat detected). Figures in brackets indicate the number of days until cameras detected a cat in each search cell.

Figure 1. Estimated probability of detection for cats (Felis catus) per search event was similar using camera traps (0.45) or wildlife detector dogs (0.54). Extensive overlap between the posterior distributions indicates no significant difference in probability of detection between the two methods.

Table 2. Power analysis showing the number of search cells required to detect a difference (pDiff) in detection probability of feral cats (Felis catus) using camera traps (pCamera) and wildlife detector dogs (pDog).

pCamera	pDog	pDiff	Number of search cells
0.1	0.3	0.2	61
0.1	0.4	0.3	31
0.1	0.5	0.4	20
0.1	0.6	0.5	13
0.1	0.7	0.6	10
0.1	0.8	0.7	7
0.1	0.9	0.8	6

Table 3. Operating cost of monitoring for cats (Felis catus) on Waitere and Toronui Stations, Hawke's Bay, New Zealand, using camera traps and wildlife detector dogs.

		Camera trapping		Predator detection dogs
	Unit price (NZD)	Number	Cost (NZD)	Number	Cost (NZD)
Batteries	1	960	960	–	–
Camera deployment and retrieval (per day)	350	8	2800	–	–
Collation of camera results (per day)	350	2	700	–	–
Vehicles (per km)	0.8	800	640	400	320
Dog team (per day)	450	–	–	10	4500
Total			5100		4820

Note: Cost estimates for dogs are extrapolated from surveys covering approximately half of each site.