Water Deer Territory & Home Range - Size

For many mammals, home range increases with the mean body mass, reflecting the greater energy expenditure of larger individuals. Similarly, ranges tend to increase with increasing metabolism, decreasing with increasing concentration of food resources. This relationship can be flexible within a given species, however, and at Branféré Zoological Park, for example, Gérard Dubost and his team found that, to the exclusion of immature bucks: "The more an animal weighed, the larger the area it occupied regardless of age, sex or season". At Whipsnade, by contrast, Stefan Stadler observed the home range size of males didn't appear to be determined by body weight, while that of adult females probably was. When population density increased at Whipsnade, territorial bucks reduced their overall range size, but kept the size of their territory (i.e., the defended bit) constant.

In the literature, reported home range size varies considerably, from about one to 700 hectares (2.6 to 1,730 acres), with ranges in winter usually significantly larger than in summer. The studies with which I'm familiar also identified larger ranges for females than males, varying with age. Stadler, for example, found that adult and subadult does had similarly sized ranges at Whipsnade, while Dubost and colleagues at Branféré, and Xin He and co-workers in China, both recorded subadults having larger (sometimes much larger) ranges than adult females. Most studies also show that does range more widely while pregnant and lactating, presumably allowing them access to a greater quantity and/or variety of food.

Based on data from 58 free-ranging deer at Whipsnade collected between November 1986 and January 1989, Stadler found that non-territory-holding bucks ranged over an average of 18 ha, while those with territories used a much smaller area of around two hectares, with about one hectare actively defended. Territorial males also significantly reduced their annual home range by up to 40% from one year to the next, while the ranges of non-territorial bucks remained broadly consistent. The average core area used by both groups did not change significantly, perhaps reflecting the quality of the territory; the core areas of territorial males were roughly half the size of those of non-territorial bucks (0.5 ha versus 1.1 ha). Also at Whipsnade, in early December in the late 1960s, Raymond Chaplin spent three hours watching the rut in Valley Meadow. In his unpublished research notes, he describes 30 adult males in the field but only four territories, each around 90 yards across, occupied by a single master buck with females resting at the centre. Assuming these were roughly square, each rutting territory would have been around 0.68 ha – broadly in line with Stadler's figures. Elsewhere in the park, I have observed an unaccompanied buck patrolling and scent-marking an area of around 1.4 ha in the eastern section of Passage through Asia, while a buck accompanied by a doe was patrolling an area of roughly 3.4 ha in the southern section of the white rhino paddock (both estimated from Google Maps).

For the Whipsnade population as a whole, home range size varied considerably from year to year, but on average adult males used the smallest annual home range at around 12 ha – significantly smaller than the 37.5 ha used by yearling males, 34 ha by yearling females, and 30 ha by adult females. Core areas from which other deer were actively excluded followed the same pattern, with adult males defending just over one hectare compared to the three or four hectares that yearling males, yearling females, and adult females tended to occupy for most of the year. Seasonal home ranges were largest between May and July, reaching 10-15 ha for females, while bucks typically ranged over less than five hectares in any given season. Fawns moved over a couple of hectares during their first three months, expanding to around 10 ha by their first winter. Young males under two years old were often observed feeding or resting within the territories of dominant bucks before being driven off, and Stadler recorded two male fawns occupying an area of around one hectare that was not held by an adult male; suggesting this may be a preferred area size when competition is absent.

Relatively few data exist from the wild. At Woodwalton Fen, limited observations on five identifiable deer during the mid-winter rut by Arnold Cooke and Lynne Farrell suggested ranges of between 5 and 15 ha. Population density estimates at Woodwalton during three rutting periods, published by Cooke and Farrell in 1981, were 0.42 per ha (1976), 0.26 per ha (1977), and 0.30 per ha (1978) – considerably lower than the densities Stadler recorded at Whipsnade of 5.8 per ha (1987) and 7.6 per ha (1988). That home range sizes appear broadly similar across two sites with such different densities and habitats is a striking finding, and may suggest that range size in water deer is relatively consistent regardless of local conditions. Anecdotally, in December 2024 I spent a few hours watching a buck with a single doe at a nature reserve in Bedfordshire, during which the male made two prolonged circuits of a field, scent-marking the periphery with urine, faeces, and preorbital secretions. I estimated the area at around 2.4 ha from Google Maps. In an adjacent field, three apparently unaccompanied bucks were parallel-walking, chasing, whickering, and scent-marking within a much smaller area of only about one hectare. Further afield, in their native China, Lixing Sun and Bing Xiao recorded bucks setting up clustered but non-overlapping territories of around 0.5 ha during the 1988/89 rut at Poyang Lake, while females ranged over a non-exclusive area of 20-40 ha, around five hectares of which was used intensively. Across the year, the Poyang females ranged over up to 120 ha; no equivalent annual range was estimated for males.

Remaining in China, between June 2010 and December 2011, Xin He and colleagues at East China Normal University radio-tracked 12 animals released into Nanhui East Shoal Wildlife Sanctuary as part of a reintroduction programme. These data are included here for reference, but they usefully illustrate how different methods of estimating home range size can produce very different results -- in this case, mean convex polygon (MCP) and fixed kernel estimation (95% FKE) -- and the figures should be treated with some caution.

In their 2016 paper in Animal Production Science, He and colleagues report MCP home ranges of between 245 and 1,559 ha, the smallest belonging to an adult male and the largest to a subadult female, with a mean of 671 ha across all tracked animals. The FKE method suggested a mean of 262 ha. By MCP, bucks had smaller home ranges than does, averaging 494 ha and 788 ha respectively, while FKE showed no significant difference, at 258 ha and 265 ha. Both methods agreed that subadult does ranged over more than twice the area of adult females and overlapped more with one another. Ranges varied with season, peaking in winter (275 ha by MCP, 403 ha by FKE) and contracting in summer (120 ha and 131 ha respectively). Home range overlap varied from exclusive -- as between bucks during the rut -- to 851 ha between a subadult and adult doe, with an average of 422 ha. Outside the rut, bucks overlapped less than does, averaging 135 ha, though two individuals overlapped by as much as 385 ha. Does appeared to overlap with one another more than they did with bucks, and the largest overlaps occurred in winter. In a short companion paper in the Pakistan Journal of Zoology in 2015, the same team noted that ranges were wider in the first six months after release before contracting significantly. This presumably reflects an initial period of exploration while the animals established familiarity with their new surroundings.

At two sites in northern South Korea, Baek Jun Kim and Sang-Don Lee of Ewha Womans University tracked four deer -- two of each sex -- between July and December 2009. The small sample size and equipment problems mean the data are highly variable and should be treated with caution, but they remain the only Korean figures of which I am aware and are included for completeness. In their 2011 paper in the Journal of Ecology and Field Biology, the researchers report a mean MCP home range of 280 ha, slightly larger at night (240 ha) than during the day (190 ha), and significantly larger in summer than spring (470 ha versus 50 ha). Males ranged over slightly larger areas than females, averaging 330 ha compared to 230 ha.

More recently, a 2021 paper in the Korean Journal of Veterinary Service by Bae Dong Jung and colleagues at Kangwon National University reported that a single female GPS-tracked for ten days during summer used between 0.11 and 28 ha per day, with a daily average of 5.3 ha – though the confidence interval of 7.4 ha underlines how variable daily area use can be. Finally, in a 2025 case report in Animals, Sohwon Bae described the GPS tracking of a young buck released following surgery to correct a dislocated hip sustained in a road traffic accident in Gangwon-do. The deer quickly established an overall home range of just over 800 ha, around 700 (87.5%) of which was used extensively.