Spring is here, and we see and hear geese flying north.
The geese, and other big birds like pelicans, fly during the day as they have little fear of predators and can withstand the stronger daytime air currents.
But we do not see the other 80 per cent of other migrating birds. These small ones fly at night, sometimes all the way from South America to the Arctic. We humans are interfering with their ability to complete their long journeys. The problem is increasing amounts of bright light thrown up into the night sky, for example from industrial sites, parking lots, car lots, sports facilities, advertising signage, security lighting, and streetlights.
Through April and early May, tiny night flyers rise high into the sky after sunset. They use the moon, the stars and geographical landmarks to navigate. Peak nights record as many as 15 million birds on the Pacific Flyway migratory route directly above us, based on data from the Cornell University Bird Dashboard monitoring station in Seattle.
Bright lights may cause the birds to circle, call to each other, descend to a lower level, or fly off course toward the lights. These diversions use up the tiny birds’ energy and reduce their chances of successfully completing their migrations.
This ecological problem has some easy solutions for individuals. Outside home lighting used to be a single porch light, left on only when someone was expected. Many of our houses and condos now illuminate facades, rooflines, garage doors, driveways, fence pillars, and even trees and landscaping – sometimes all night long.
How about you – are your home or condo outdoor lights shielded from above to reduce light escaping into the night sky? Are your safety and security lights directed downward where they are needed? Could you use motion-activated lights instead? If you have lighting that is solely decorative, could you turn it off during the spring and fall bird migrations?
Reducing home lighting will also help local birds, pollinators, and wildlife which need a dark period every 24 hours for foraging, rest, and reproductive behaviour. It may relieve any neighbours into whose windows your lights intrude. And you will lower your energy consumption and extend the life of light fixtures eventually destined for recycling or landfills.
Perhaps you remember our velvety night sky of 50 years ago? Wouldn't it be a pleasure to stand outside in the moonlight and look up to see that same sky, once again hung with thousands of stars?
Peak spring bird migration for our area is from now until mid-May. Turn off your lights – birds overhead!
Janet McIntosh writes on behalf of the White Rock and Surrey Naturalists Society.
