Photo Credits: Zoe Lucas
Originally published December 2001 by the Sable Island Preservation Trust
Winter is here. On Sable Island the lush green of dune vegetation has been replaced by sandy golden tones as the leaves of beach grass die. In winter the island’s treeless landscape and adjacent seascape are windswept and bleak, but contrary to some accounts, the environment on Sable Island is not harsh. The island’s climate is temperate oceanic and is generally milder than that of mainland Nova Scotia. Winter temperatures, normally between +5 and -5 degrees Celsius, rarely drop below -13 degrees C, and snowfall is usually far less than that on the mainland. The surrounding ocean accounts for the island’s milder temperatures. During the summer surface waters of the ocean are heated by the sun, and during winter the ocean warms the cooler air passing over it, thus Sable Island is surrounded by a huge “hot water” heating system. Although the Gulf Stream passes several hundred kilometers south of the island, it has little affect on the island’s climate.
Spring, summer and autumn are certainly the more “comfortable” and colourful months on Sable Island, but winter is particularly interesting because the season brings changes in the habitat and behaviour of the Sable Island horses. The population fluctuates in number from year to year, but on average there are about 250 to 300 horses on the island. They are protected by law from interference by people, and thus live wild and undisturbed. They live in family bands of two to ten individuals, males and females, adults and young. At any given time, roughly a third of the males in the population are not members of family bands, and they wander alone or in loosely structured all-male groups. During August through October, the Sable Island horses prepare for winter. Grazing on the plentiful vegetation, including the highly nutritious beach pea, of late summer and early autumn, they put on weight, and they don their winter coats. As early as August, the horses’ coats start to thicken, and by December their coats are `woolly’. The younger the horse, the thicker the coat. The long hair of winter, particularly around the head and neck gives the horses a big-headed awkward look, and has given rise to some unflattering accounts of the Sable Island horses. (Anyone interested in the history of the horses should read “The Horses of Sable Island” by Barbara J. Christie, Pottersfield Press 1995.)
Most horse mortality occurs during mid-winter through early spring, and ranges from very low (less than 5%) in some years, to infrequent highs of roughly 25% or more. In winter the horses’ grazing behaviour and range use changes. Band stallions tend to be less concerned about the proximity of other bands (and their stallions), and it is not unusual to see several family bands grazing together and mingling in shelter areas. From the point of view of two- and four-legged mammals on the island, the most severe element in any season is probably the wind. Prevailing winter winds are northwesterly and average 40 km/hr, and often gusting to 100 km/hr. In such conditions the horses huddle in the lee provided by the dunes, or turn their tails to the wind and graze, and people working out on the dunes or beaches bundle up in windbreakers or rain gear, and don ski-goggles to protect eyes from blowing sand. When heavy snowfall covers the island, horses often forage by eating the grass beneath while using their noses to push away the snow. But the wind can be a great help because it blows accumulated snow into drifts and sweeps clear wide areas of vegetation. The weather on Sable Island is very changeable, and during any winter day, there can be windblown sleet and snow one moment, and sunshine and light breezes the next. During winter the horses spend somewhat more time grazing, but they also wander on the beach, gallop and wrestle with each other in the heathlands, and spend long hours snoozing in the sun.
Zoe Lucas has been contributing to the study and preservation of Sable Island’s unique ecosystem for 30 years.