Feral ferrets (Mustela furo) as hosts and sentinels of tuberculosis in New Zealand

Figures & data

Figure 1. Estimated age-specific prevalence of tuberculosis (TB) in a sample of 407 ferrets (Mustela furo) from Molesworth Station in the Marlborough region of New Zealand. Age classes are monthly below 1 year, then pooled for 16–18 months old and >23 months. Age-specific prevalence of TB was estimated by ageing all infected ferrets and a random selection of uninfected ferrets, using the latter to estimate the age distribution for all uninfected ferrets (from Nugent and Whitford 2008).

Table 1. Estimates of feral ferret (Mustela furo) densities (per km²) for different habitats in New Zealand.

Study site		Estimate	Time of year	Habitat	Technique^a	Reference
North Island sites
	Hohotaka, Manawatu-Wanganui	3.1	Summer	Pasture	Removal	Caley and Hone (2005)
	Rangitikei, Manawatu-Wanganui	2.0	Summer	Pasture	Removal	Caley and Hone (2005)
	Waipawa, Hawkes Bay	1.2	Summer	Pasture	Removal	Caley and Hone (2005)
	Castlepoint, Wellington	1.1	Summer	Pasture/Scrub	Removal	Caley and Hone (2005)
	Cape Palliser, Wellington	0.6	Summer	Pasture/Scrub	Removal	Caley and Hone (2005)
South Island sites
	North Canterbury	5.3–7.3	All year	Pasture	Trap catch index	Caley et al. (1998)
	North Canterbury	0–6.39	All year	Pasture	Mark-recapture	Morley (1999, 2002)
	North Canterbury	1.5–3.1	Summer/autumn	Pasture	Petersen estimate	Caley and Morriss (2001)
	Mackenzie Basin/Central Otago	2–5	All year	Semi-arid tussock	Minimum left alive	Moller et al. (1996)
	Palmerston, East Otago	5.3–6.3	Autumn	Pasture	Removal trapping/mark-recapture	Cross et al. (1998)
	Macraes, Central Otago	4.4	Summer/autumn	Tussock grassland	Removal trapping	Middlemiss (1995)
	Central Otago	1.6–10.1	Summer/autumn	Semi-arid tussock	Mark-recapture	Norbury et al. (2004)

^a Standard methods for estimating mammalian abundance, as described in Seber (1973); and Krebs (1998)

Table 2. Home range sizes (hectares) of male and female ferrets (Mustela furo) in the South Island of New Zealand.

		Mean (min, max) home range and sample size
Study site	Season	Males	Females	Reference
Mackenzie Basin	Varied	288 (190, 372) (n=5)	111 (44, 225) (n=7)	Pierce (1987)
East Otago	Autumn/early winter	86 (39, 131) (n=7)	45 (18, 89) (n=10)	Ragg (1997)
Otago/Mackenzie Basin	All year	102 (19, 316) (n=34)	76 (16, 240) (n=28)	Norbury et al. (1998b)
Otago Peninsula	Spring/autumn	163 (95, 220) (n=6)	135 (73, 206) (n=10)	Moller and Alterio (1999)
North Canterbury	Winter/spring	194 (60, 320) (n=5)	99 (50, 150) (n=10)	Spurr et al. (1997)
North Canterbury	Summer/autumn	139 (2, 220) (n=4)	151 (62, 314) (n=4)	Young (1998)
North Canterbury	Summer/autumn	80 (n=1)	128 (28, 265) (n=11)	Young (1998)
North Canterbury	Summer/autumn	760 (n=1)	230 (n=5)	Caley and Morriss (2001)
Central Otago	Autumn/winter/spring	94 (68, 120) (n=3)		Baker (1989)
Central Otago	Autumn/winter/spring		59 (40, 79) (n=8) (fully described ranges)	Ragg (2002)
Otago Peninsula	Winter	107 (n=1)		Dymond (1991)
Inland Marlborough	All year	178 (63, 294) (n=5)	52 (13, 91) (n=7)	Yockney et al. 2013 (adapted from Byrom et al. 2008)

Table 3. Percentage of ferret (Mustela furo) carcasses visited by each of five wildlife species and two livestock species in summer and winter, with average time to first discovery for carcasses visited, and the percentage of carcasses touched or sniffed, licked or fed upon. There were 13 ferret carcasses in summer and 20 in winter (from Byrom 2004).

Species	Season	Carcasses visited (%)	Average time to discovery (hours)	Carcasses touched or sniffed (%)	Carcasses licked (%)	Carcasses scavenged (%)
Possum	Summer	38	21	38	0	0
	Winter	55	49	45	10	0
Ferret	Summer	38	11	38	0	31
	Winter	10	128	10	5	0
Cat	Summer	31	57	31	0	24
	Winter	30	12	30	15	0
Australasian	Summer	31	105	31	0	31
harrier	Winter	15	20	15	0	15
Hedgehog	Summer	31	27	31	0	5
	Winter	25	72	25	5	5
Cattle	Summer	ND	ND	ND	ND	ND
	Winter	25	54	25	0	0
Sheep	Summer	8	100	8	0	0
	Winter	5	97	5	0	0

ND=Not assessed at that time

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