Britain

In Britain, stoats are larger than in Switzerland, and eat rabbits much more often than water voles (see Figure 5.1B). Rabbits were introduced to Britain in

Norman times, but have been common for only the last 200 years or so; stoats are native, and were among the very first postglacial colonizers (Yalden 1999). For almost all the time that stoats have lived there, Britain was largely forested. Until the beginning of deforestation by humans in the Neolithic age, the normal diets of stoats must have been very different from what we see now. Most often, they would have hunted bank voles, wood mice, and red squirrels in the forest, instead of the much more abundant rabbits and field voles of the modern open country. The historical deforestation and increases in agriculture, which have favored the small mammals of fields and hedges at the expense of the mammals and birds of the native woodlands, must also have allowed a considerable historical increase in the average density of stoats.

Many rabbit populations do not show the great ups and downs in numbers that water voles do, so the extent of the British stoats' dependence on them was unknown until 1953-1955. In those years, myxomatosis arrived and spread throughout the islands, and about 99% of all rabbits died (Sumption & Flowerdew 1985). The consequences were sensational—for the vegetation, for small rodents, and for their predators. The upheaval that shook the entire woodland community was very clear in the data of Southern (1970), who documented spectacular swings in the densities of forest rodents and the breeding success of tawny owls in Wytham Wood over the few years following the collapse of the rabbit population. No one was studying stoat populations in Britain at the time, but from another source of information we can see very clearly the impact of the arrival of myxomatosis on stoats.

The "vermin books" of well-organized game estates often contain long sets of figures showing the numbers of predators killed every year. Stoats were always among the greatest enemies of the traditional gamekeeper, for whom every kill was a source of satisfaction. Some keepers used to hang the carcasses along a strategically located fence, accumulating a somewhat macabre "gibbet"—a display intended to demonstrate to their employers the results of their hard work (see Figure 12.2). But in the years immediately after myxomatosis, stoats practically disappeared from the countryside, and from the gamekeepers' gibbets.

Vermin bag records from estates all over the country showed the same remarkable exodus. On one English estate of 9,300 ha with a particularly long record (Figure 10.2), the tallies dropped from 409 to 1,013 a year before the epizootic to 40 to 257 afterward (King 1980c). In the records of another estate in Hampshire of 1,600 ha (Anon. 1960), only 13 to 58 stoats were killed each year from 1954 to 1960, compared with 136 to 302 each year from 1947 to 1953.

Over the whole of Britain, stoats remained scarce until the 1960s, when rabbit populations began to recover, followed by stoat populations. For a decade or so, the bag records for rabbits and the numbers of stoats killed each year by gamekeepers increased together. From the middle 1970s, the national toll of stoats decreased again (Figure 10.2, inset), even though the numbers of rabbits

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Year

Figure 10.2 The vermin bag records of an English game estate illustrate well the close relationship between the numbers of stoats and rabbits killed on agricultural land under long-term, consistent management, and especially the effect of myxomatosis in 1953. Inset: In Britain generally, the recovery of rabbits accelerated after 1990, but gamekeepers' trapping effort has decreased. The average relationship between stoats and rabbits killed on estates throughout Britain for 1960 to 2004 does not show the close relationship typical of local data. Stoats have solid line; rabbits have dotted line. (Data from the Game Conservancy, courtesy of S. Tapper.)

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Year

Figure 10.2 The vermin bag records of an English game estate illustrate well the close relationship between the numbers of stoats and rabbits killed on agricultural land under long-term, consistent management, and especially the effect of myxomatosis in 1953. Inset: In Britain generally, the recovery of rabbits accelerated after 1990, but gamekeepers' trapping effort has decreased. The average relationship between stoats and rabbits killed on estates throughout Britain for 1960 to 2004 does not show the close relationship typical of local data. Stoats have solid line; rabbits have dotted line. (Data from the Game Conservancy, courtesy of S. Tapper.)

continued to increase—and after 1990, to soar (Tapper 1999). This time, the decrease in stoat kills has been less to do with stoat population densities than with changes in gamekeeping strategy and reduced trapping effort (McDonald & Harris 1999).

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