For people who enjoy watching birds, there is no better season than right now. The early mornings are filled with the songs of male birds calling for females and every day, more species of migratory birds arrive from their southern winter homes to nest here during the summer.
One of the best local places to view birds is at Colony Farm Regional Park where over 200 species have been identified to date including the beautiful lazuli buntings. Throughout the month of May, several species of birds, including warblers, swallows and flycatchers have been arriving at the park to find mates and initiate a new nesting season.
One of the features that attract birds to Colony Farm is the old-field habitat - the tall grass fields which mimic the natural meadows once found at the edge of the advancing Fraser River delta. As a consequence, the park attracts some species which are now rarely found elsewhere in the Lower Mainland.
Often, it takes a magical combination of several features to create ideal nesting conditions. Breeding birds need to be close to reliable sources of food, which they will feed to their young. They also need safe nesting areas, often hidden deep within a thicket or sometimes even close to the ground in a tangle of grass. Finally, most male birds like to have some sort of perch close to suitable nesting habitat from which they can attract females.
Every year, millions of birds that spend most of their time in tropical areas, fly north each the fields and forests come alive every summer with a bounty of insects. Long before the advent of chemical pesticides, farmers relied on migratory birds to help them keep populations of harmful insects under control.
Now the tables have turned.
Farmers who rely on pesticides to boost crop production are often unwittingly harming juvenile birds, which are fed a steady diet of pesticide-poisoned insects by their doting parents.
While some of the mysteries of bird migration have been unraveled in recent years, there is still much to learn. Through techniques such as bird banding and the use of very light weight transmitters, biologists have learned that most small songbirds migrate at night. They apparently have the ability to take a bearing on the setting sun and fly along migratory routes established over time with the evolution of each species.
Each night they may fly 300 kilometers or more. As dawn approaches, they must stop to rest, feed and gain sufficient energy for the next night's journey. Only birds that find sufficient food throughout the day will have the energy to continue their flight at sunset. Thus, these migratory birds are highly dependent on finding critical layover stops along their way.
If a forest has been logged in the past year, a wetland drained or a field developed into suburbs, some birds could perish when they discover the habitat they relied on as a fuelling stop has vanished. In general, migratory birds predominate among the bird species that are undergoing dramatic population declines. Speculation is that a dependence on critical habitat throughout their migration corridors puts these birds at higher risk from habitat loss than birds which stay in the same place all year.
I fondly remember when barn swallows and tree swallows were a common sight on my street. Sadly, I have seen neither species for several years in my neighbourhood.
Individual birds tend to return to the same nesting areas. After all, if they nested successfully one year, it only makes sense for them to return to a familiar area where they know the location of the best food sources. Thus, the rufous-sided hummingbirds you might see in your yard this spring are probably the same ones or the offspring of the ones present last year.
In my backyard, male black-headed grosbeaks arrived from southern Mexico right on schedule on May 14. The first female arrived in our yard on May 17. While these adult birds enjoy feasting on black oil sunflower seeds, when it comes time to feed their young, they will switch to catching insects. The annual return of these migratory birds gives me faith and hope in the ongoing cycles of nature and encourages me to continue working to preserve wildlife habitat.
For people who wish to learn more about migratory birds and enjoy viewing them, free birding walks will be offered this weekend at Colony Farm Park. Among the many birds expected to be seen will be black-headed grosbeaks, common yellowthroat warblers, cedar waxwings and the spectacular lazuli bunting which migrates from Mexico and typically arrives at Colony Farm Park in the third week of May. These walks which will last for about 2 hours will start at 9 am and 3 pm on Saturday, June 1.
The walks will depart from the parking lot at the end of Colony Farm Road in Coquitlam and will be led by experienced members of the Burke Mountain Naturalists and Colony Farm Park Association. The walks will be on level ground and suitable for all ages.
