BY THE BAY: A vulnerable time of year for birds
Last month was a busy time of year for birds, with many local species building nests and laying eggs, with others heading through on migration.
Barn swallows that nest under the eaves of farm buildings have flown from as far as South America to raise their broods in the Fraser delta. The bright yellow, common yellowthroat, a small songbird, may have wintered in Central America, yet is back at Blackie Spit.
The rufous hummingbird, one of our smallest birds, made the journey from Mexico, powered on nectar from flowering plants. The male bird’s plumage is orange-red, in contrast to the deeper crimson of the Anna’s hummingbird, our only wintering hummer.
Bird nests come in all shapes and sizes, from the massive construction of bald eagles, weighing up to a tonne and reaching up to three metres in diameter, to the bushtit’s intricate hanging pocket made of interwoven lichens and mosses, lined with feathers.
Not all nests are in trees or shrubs; some birds nest on the ground.
The northern harrier, a graceful hawk that patrols the shores of Boundary Bay, makes a pile of vegetation among sedges, hardhack and rough grassland. Savannah sparrows build their nest under tufts of grass or near an old log.
Shorebirds like the killdeer and black oystercatcher hardly make a nest, just scooping a depression in the sand and gravel to lay their eggs.
The eggs and young of all such ground-nesting species are vulnerable, so it is extra important to keep dogs out of wildlife areas and under control.
Sometimes young birds leave the nest before they are fully fledged. When this happens, the parent birds will often stay close in order to feed and defend them. It is best not to “rescue” such baby birds, as if they are strong enough to survive they will do better under the parent bird’s care.
At the same time as local birds are singing, laying eggs and raising chicks, other birds are still moving through the delta, heading further north to breed. Huge flocks of snow geese have been feeding in farmers’ fields.
Mid-April was also the peak of the sandpiper migration, as thousands of these little shorebirds stopped to feed on the mud flats of Boundary Bay and Roberts Bank. Their migration journeys have taken them from South America via Panama Bay and San Francisco, with thousands of kilometers to go to the Yukon Delta for their short breeding season.
Stopping to fuel up on microscopic animal and vegetable matter in the mud and shallow water of the Fraser delta is a critical part of their survival.
Shorebird numbers are declining around the world as so much of their vital shoreline habitat is lost to urban and industrial development.
Sandy beaches along the waterfront at White Rock are often too busy with people and dogs for wary birds like sandpipers to feed. Roberts Bank, Delta, is a Wildlife Management Area, yet there is a high risk that a proposed Terminal 2 expansion at Deltaport will cause ecological changes that will be detrimental to shorebirds and other species.
Let’s make sure we save places for birds and other wildlife that rely on natural habitats, so that spring remains alive with the sounds of nature.
Anne Murray, the author of two nature books, writes monthly in the Peace Arch News – www.natureguidesbc.com