Save our squirrels – but just the red ones

October 2005

by Mel Tonkin

The red squirrel is one of our favourite mammals, not least because this is one of the few regions in Britain where it is still found in reasonable numbers. Out of 127 woodlands around the country selected for priority red squirrel conservation, 36 are in Grampian. There are strong populations in Deeside, Donside and Speyside, with smaller scattered populations in woodlands near Ellon and Fyvie.

The woods of Deeside and Donside are critical areas due to invading grey squirrels. Unfortunately, they were introduced into Aberdeen in the Fifties and are spreading out of the city along the Dee and the Don. Grey squirrels can now be found in Peterculter, Banchory, Tarland and Bennachie.

Red and grey squirrels rarely co-exist in the same area indefinitely. This is not due to direct aggression by greys, yet in most cases red squirrels become extinct within a few years, or sometimes decades, of the grey squirrel’s arrival. The reasons are complex.

Grey squirrels move about on the ground much more than red squirrels, and in autumn can gain an extra 23 percent of body weight as fat stores, compared to just 12 percent for red squirrels. This allows greys to spend far less time foraging in cold winter weather, when reds are forced out to find food.

Yet how much do most people know about the red squirrel? There are around 121,000 in Scotland (75 percent of the UK total) Its coat is chestnut to almost black on the back, white on the underside. The winter coat is thicker than in summer, and either darker or densely flecked with grey. The summer coat is brighter, and the limbs are chestnut all year round. The characteristic ear-tufts and the tail moult once a year, in early autumn; they begin dark and fade throughout the year to become pale, even straw-coloured, by early summer.

The red squirrel is active in daylight, especially in the early mornings. Its favoured habitat is woodlands. It is most abundant in Scots pine or mixed conifers, or in broadleaf woodland, especially where hazel is plentiful. It eats tree seed of pine and other conifers, hazel, beech, wych elm and yew. When seeds are not available, it eats leaf and flower buds, young shoots, flowers, fungi, sappy tree bark, insect pupae and grubs. The large upper incisors enable it to gnaw rapidly through tough pine-cone scales and nut shells, and manoeuvrable lower incisors allow fine manipulation, so that it can extract even the tiniest conifer or elm seed from its papery seed-coat.

Because of its dramatic decline, people regard the red squirrel as a fragile creature, apt to expire from shock if interfered with, but this is far from the truth. In my live-trapping study in Cumbria, several squirrels were caught more than 100 times over a two-year period with no ill effect.

Red squirrels showed a remarkable capacity to maintain their numbers when heavily exploited for the fur trades of Scandinavia and the former Soviet Union. The red squirrel, Sciurus vulgaris, is the most widely distributed of all tree-squirrels worldwide, occurring from the western seaboard of Europe across to the Pacific coast of Asia, and from the northernmost Arctic taiga forests to the Mediterranean. This is a remarkably successful species.

Superbly adapted for arboreal life, they have relatively long limbs, large reversible hind feet and grasping fore feet with needle-sharp claws for climbing; the broad tail, which they use for balance, acts as an aerofoil when they are leaping from tree to tree. Excellent distance judgement and spatial navigation ability enables the squirrel to anticipate the best route through a complex three-dimensional environment. Smaller and lighter than the grey squirrel, it can exploit food sources on even the most fragile branches of the tree.

But the fact remains that red squirrels are losing ground, year by year, to greys. The Borders seem set to lose theirs from all but a handful of forests, despite huge efforts over many years to control greys. Dumfries and Galloway still have good red populations, but greys are starting to make inroads from north and south. In the Central Belt grey squirrels are ubiquitous, as far up the Forth valley as Aberfoyle. On the Tay, greys have almost reached Aberfeldy and in Deeside they have spread up the valley from Aberdeen as far as Aboyne, and up the Don to Bennachie.

It is difficult to predict the outcome of this grey range expansion. In oakwoods the grey squirrel has the advantage: its ability to deal with the anti-digestive agents in acorns gives it a food source that cannot be exploited by reds. The grey squirrel is also resistant to a squirrel pox virus which devastates red squirrel populations. Up till now Scotland has been free of squirrel pox, which may be why the replacement of the native species by the invader has been much slower than in England. However, three grey squirrels carrying antibodies to the virus were recently discovered just north of the English border, so we cannot assume that this will always be the case.

In more northerly areas the productivity of food trees may be lower than further south, restricting the spread of greys. But it seems possible that red squirrels will eventually be lost from mainland Scotland.

The cutting down of mature conifer woodland – for building developments or new roads – reduces their habitat and may cut off small groups from the main centres of population, making them vulnerable. However, it remains the case that commercial forestry provides most of the red squirrel’s remaining habitat.

Attempts to control greys have largely failed. The current strategy is to protect certain choice red squirrel forests by trapping incoming greys in a wide zone around the perimeter. In this way we aim to preserve red squirrels in at least some forests. We can favour red squirrels by cutting out the greys’ favourite food trees – oak, beech, chestnut – and improving the conifer mix and seed-productivity. This runs counter to woodland management for improving biodiversity, so it has to be restricted to a few sites.

We desperately need a better knowledge of the distribution of both species, and reported sightings of red squirrels help us to build this picture. We also need to study the relationship between the two species in areas like Dunkeld and Deeside, where the red squirrel seems to be holding its own in the presence of greys. A proper understanding of the ecology of the red squirrel in a range of woodland habitats would allow us to predict its fate with greater certainty.

If you own or manage woodland, get advice from your local squirrel group or from the Forestry Commission on how best to manage it to encourage red squirrels. If you have municipal woodland on your local patch where there are red squirrels, campaign to have the site managed for red squirrel conservation.

Please send in any sightings of red squirrels in the Grampian area to Gavin Legge at the Grampian Squirrel Group on 01466 794542, or report them online on www.grampiansquirrelgroup.co.uk. For sightings outside Grampian, send them in to the Scottish Squirrel Survey co-ordinator, Mel Tonkin (email: mtonkin@swt.org.uk; tel: 0131 312 4733)

Mel Tonkin is funded by Scottish Natural Heritage to be the Scottish red squirrel survey coordinator. She is fascinated by this small mammal, which still has a stronghold in Grampian, and encourages readers to contribute to the survey.

This is an article from the October 2005 edition of Leopard Magazine. To read much more like this every month, subscribe to Leopard Magazine.