Ecological Balance (Hansard, 4 March 1993)

§ Mr. Maclean

There is some difficulty in assessing what, if any, effects a given species has on the ecological balance throughout the United Kingdom. There are continual fluctuations in populations, with each variation being dependent upon many factors and the ecological balance can be seriously disturbed locally without the overall United Kingdom balance being disturbed.

The grey squirrel is a non-native species and now has spread through most parts of the United Kingdom. The only areas free from grey squirrels at present are north Scotland, Cumbria, Northumbria, Isle of Wight and north Wales. In all other areas which have been taken over by greys and where reds have become extinct, the reds have never managed to re-colonise. In coniferous habitats the populations of reds and greys are more evenly balanced. Grey squirrels also cause serious damage to growing timber and sometimes cereals, fruit, bulbs and crops.

Foxes can have severe localised impacts on ground nesting bird colonies if not controlled. For example, the RSPB is having to destroy foxes on the Abernethy game reserve because of the damage foxes are causing to the rare capercaillie. English Nature is also having to take similar action on one of its nature reserves. Apart from farm animals and birds, the main wildlife killed by foxes are: small rodents, earthworms, insects and rabbits.

Mink have spread throughout all parts of the United Kingdom and have even managed to swim the stretches of water and have colonised parts of the Western Isles. Detailed studies show that, overall, they have little impact so far on prey populations on mainland Britain although they have severe localised impacts on ground nesting bird colonies. Studies show that mink main food sources are fish, frogs and waterside birds especially moorhen, loot and mallard. Competition between mink and otter occurs when food sources and suitable breeding habitats become scarce.

Canada geese numbers are increasing rapidly from 19,000 in the 1970s to over 60,000 now. This non-native species causes damage to crops as well as amenity land in parks, public open spaces and golf courses. Goose droppings may pose health and safety risks and standing water in lakes become polluted. The geese can be aggressive while they are breeding and there are indications that the species competes with other wild birds for food and nest sites. My Department has set up a working group to assess the possible impacts on the environment, target appropriate research and plan a strategy for managing the species.

In the past 20 years sparrow hawk populations have increased rapidly from a low in the 1960s. There are now 25,000 breeding pairs, plus around 30,000 non-breeders. There is insufficient evidence to show what the effect is on other bird species, but their main food sources are small birds.