September brings shorter days, longer nights and Okanagan hillsides sprinkled with the golden tufts of Rabbitbrush. But change has been in the air for some time now. By September, seasonal migrations are well underway. By mid-August you would have noticed that your hummingbird feeder didn’t need to be filled as often, and by the time you read this, there may be no hummingbirds at all. In early July, feeders were a frenzy of hummingbird activity. By early August only females and juveniles remained. Most male hummingbirds had already departed for points south, although it seemed this year that summer had just begun.
British Columbia comprises varied and extensive breeding territory for many birds, and the Okanagan Valley provides an important corridor for their latitudinal (north/south) migrations. Birds begin to migrate south as early as late July, moving from breeding to winter habitat. By the first week of September, migrating hawks, ducks, sparrows and blackbirds join the flow. Ospreys, nighthawks and meadowlarks have departed by mid- to late September. Bluebirds, with the exception of those few that over-winter in the valley, are en route as well. Summer’s Cedar Waxwings will soon be replaced by fall and winter’s Bohemian Waxwings — both berry loving birds.
The onset of annual hummingbird migrations heralds not only departures of locally nesting birds, but the “fly-bys” of northern breeders as well as the arrival of over-wintering populations. By the end of August, shorebirds from northern British Columbia wing their way south through the Valley. In just the past week sanderlings, horned grebes and common loons have been seen on the Penticton Okanagan Lake waterfront, a sure sign that fall is here — no matter what the temperature. Some birds that breed in northern and central Interior regions of the province migrate to the Okanagan to over- winter. Swans may be found throughout the winter on Vaseux and Skaha lakes. Altitudinal migrants such as chickadees, nuthatches and juncos, which have adapted their breeding range to higher elevations, return to lower elevations. Most winter residents have returned to the Okanagan by the end of November.
Humans have long speculated about bird migrations. Knowledge of breeding ranges, wintering grounds and migration routes have increased significantly in the past few decades, but some aspects of seasonal flights remain less well understood.
Avian methods of navigation are complex, utilizing the sun and magnetic fields as well as visual maps. While there is a strong genetic component to migration, environmental influences are also significant. Storms and inclement weather, as well as anthropogenic impacts such as habitat loss, may impact flight paths and destinations. Birds’ ability to weather the migration process demonstrates a tenacity and complexity that human efforts, even with GPS systems, cannot emulate. The 4,500-kilometre migration of Calliope hummingbirds (the smallest North American bird) from breeding sites in the Okanagan to south-central Mexico reflects the workings of a natural world we do not fully acknowledge or comprehend.
Why do bird migrations attract our attention? The ‘Survival’ factor is one reason. The ability of small, vulnerable creatures to complete such long, arduous journeys engages both hearts and minds. Migration also extends our gaze beyond the local, reminding us of the interdependency of natural environments. As well, it alerts us seasonally to the unique character of our own natural environment. Migration reflects the direct dependence of many species on this particular South Okanagan habitat. The ‘here today, gone tomorrow’ character of migrating birds and their reliance on our local habitat supports not only observations, but protection of this local environment.
Over the next few months, keep a look-out for migrating birds. From your backyard to Vaseux Lake migrants are everywhere. Listen for the gurgle of Sandhill cranes, and look up, high, higher, until you can see specks of flight, heading south. Now you see them, now you don’t!
For a really close up view of migrating birds visit the Migratory Bird Observatory a few hundred metres north of the Vaseux Lake wildlife viewing area — watch for the cars parked by the road; visitors are welcome every day from dawn until about noon.
The South Okanagan Naturalists’ Club resumes its monthly meetings on Sept. 22 at the Penticton United Church at 7:30 p.m. All are welcome. For program details check out our website: www.southokanagannature.com.
Melody Hessing is a member of the South Okanagan Naturalists’ Club.