Spring is here — at least according to the birds.
What a great time of year — no matter how badly we have managed to mess things up environmentally (and make no mistake — we have messed up badly), nature temporarily forgives us and puts on a marvelous show of renewal.
The weather may not turn warm and sunny exactly when we want, but turn it does, and with it comes tree buds bursting, flowers blooming and birds and butterflies in abundance. All of these things are closely interrelated, of course. The tree buds attract insects as they open, and the insects in turn attract the birds which feed on them. Other birds, such as hummingbirds and orioles, depend on the nectar from flowers for a large portion of their food source. If the birds arrive too early (or the plants and insects peak too late), trouble ensues.
Anecdotal data from across the U.S.A. and also from southern B.C. suggest that many birds are arriving from one to three weeks earlier than normal this year. But some other birds appear to be just about on time.
The first rufous hummingbirds were reported in Oliver on April 12, which is almost exactly when they normally arrive. In contrast, the first western kingbird was spotted in the South Okanagan on April 6, which is substantially earlier than usual.
Much of the U.S.A. has “enjoyed” a significantly warmer than normal winter and this may have contributed to birds moving north at a faster rate. It is not easy to relate bird migration solely to weather along their migration route, however, since other factors, such as length of day, also enter into their migration triggers. And certainly, while they spend their winters in Central and South America, they would have no knowledge of what the weather is doing in the north.
Of course, when we speak of average or “normal” arrival dates we really are speaking of a range of dates, because every year varies somewhat from other years. Numerous other species of birds have now arrived in the valley, including most swallows, ospreys and some warblers. Thousands of sandhill cranes have been passing overhead, which is typical of this month.
In addition to birds heralding spring, it is always a pleasure to see a variety of butterflies appear on the scene. Unlike birds, butterflies do not undertake true migration, with the exception of the monarch butterfly. So most butterflies that we see in the spring are newly hatched although many species do emigrate — that is they undertake one-way migrations.
Unfortunately the news about monarch butterflies is not at all good. Butterfly researchers at Texas A&M University estimate that monarch numbers will be down about 30 per cent this year. More importantly though than any single year is the fact that monarch populations have been in a long downward trend ever since official surveys began in 1994.
As with most declining populations (whether birds or some other species), the prime cause appears to be loss of suitable habitat. Nearly all monarchs overwinter in the state of Michoacan in Mexico or in coastal California. Equally important is suitable habitat along the migration routes through the central U.S. and along the west coast. Milkweed plants are absolutely essential to breeding for monarchs. You can help by planting milkweed (native to the Okanagan) in your yard.
In celebration of its 50th anniversary, The South Okanagan Naturalists’ Club and The Nature Conservancy of Canada (also celebrating its 50th anniversary) are joining with the Penticton Museum in presenting the exhibit Wild at Heart, on until Aug. 31.
Amongst its many activities, the South Okanagan Naturalists’ Club has a weekly bird outing on Thursdays. Learn more about this and other club activities at: www.southokanagannature.com.
Robert Handfield is the past-president of the South Okanagan Naturalists’ Club.