Contrasting habitats

Saturna Island may be close, but has plenty of differences

Mount Warburton Pike, the highest point on Saturna Island in the southern Gulf Islands, rises on the horizon across the Strait of Georgia.

I spent a recent weekend on the island watching the daily life of the coastal forest unfold, a peaceful interlude that vividly illustrated the incredible importance of habitat.

Saturna lies only 22 km south of Tsawwassen as the eagle flies, yet the scenery and vegetation of the sunny, south-facing slopes are markedly different. Garry oaks cling to craggy bluffs of honey-coloured rock, and the dry coastal woodland has predominantly Douglas-fir and tropical-looking, shiny-leaved arbutus trees.

Only on the damper, northern slopes of the hillsides do you find the cedar-hemlock forests typical of the mainland. Many of the wildflowers are natives, such as the tangling strands of purple honeysuckle on the forest floor, yellow clumps of monkey flower, and the nodding onion and fawn lilies of the grassy bluffs.

The wildlife is different too.

Young ravens called raucously from the tree tops but the ubiquitous suburban crows were absent.

Turkey vultures, large birds only occasionally seen over Tsawwassen, circled in groups of four or five in the blue sky above the Saturna vineyard.

Carrion must be plentiful on this rocky island where black-tailed deer and feral goats clamber up and down the steep, waterfront cliffs. Many of the songbirds are different too: chestnut-backed chickadees replace black-capped chickadees, purple finches are commoner than house finches, and cheerful house wren families are everywhere, their energetic trilling songs reverberating from every brush and rock pile.

While not unique to the Gulf Islands, these birds are all at home in the dry forest conditions, as are the large pale swallowtail butterflies that float through the woodland, and the alligator lizards sometimes seen basking on a rocky outcrop.

Other species once common on the mainland are hanging on in this less-developed island: flycatchers, thrushes, warblers and pileated woodpeckers, for example, have declined in Delta as forests were replaced by residential developments.

On Saturna, Pacific slope flycatchers and Swainson’s thrushes called ubiquitously, and jewel-coloured orange-crowned and Townsend’s warblers were feeding young ones.

Old growth Douglas-fir stands and an abundance of dead snags ensure the survival of woodpeckers, brown creepers and red-breasted nuthatches.

Point Roberts was an island before the Fraser delta accumulated, joining it to the mainland about 2,500 years ago. The river’s influence extends to Galiano Island, with the milky plume of sediment-rich waters reaching that island in spring freshet.

However, the Strait of Georgia has remained an impassable gulf for many species and created a haven for others. The temperate microclimate has nurtured the coastal Douglas-fir forest, a habitat type that has been lost on most of mainland British Columbia.

The wealth of that habitat was very visible this Saturna summer weekend.

Anne Murray is the author of the ecological history, Tracing Our Past ~ A Heritage Guide to Boundary Bay, and A Nature Guide to Boundary Bay. Both books have photographs by David Blevins, and are available at local booksellers or online at www.natureguidesbc.com.