GOLDS: Spring is in the air and so are birds
Even though we had only about a week of real winter weather, I am ready for spring. And so, I notice, are the plants as I can see their green tips emerging from the ground through the decomposing leaves that have protected them from winter frosts. Already, flower heads are forming on the Oregon grape while snowdrops have been blooming for some time.
The Earth is reawakening and we are about to be enveloped by one of the loveliest seasons of the year.
While only a few birds are nesting this early in the season, they will soon be followed by many more. Among the early nesters are the Anna’s hummingbirds as well as some species of raptors such as bald eagles. Most resident birds are just on the verge of shifting into their spring behaviour of finding mates and searching for appropriate nesting sites. It can be interesting to watch them at feeders now as pairs form from winter flocks.
Snowfall at higher elevations has kept varied thrushes in our neighbourhoods but they will soon return to these forests to begin the nesting season. I can already hear the “fee-bee” mating song of the black-capped chickadees, although I have not yet noticed any activity at the chickadee nest boxes in our yard.
February is spring-cleaning month for the Burke Mountain Naturalists as members devote some of their time every weekend to cleaning and monitoring about 300 bird nest boxes they have installed in several regional parks. Only birds that use natural cavities for nesting will use a nest box. Such nest boxes are especially attractive to the so-called secondary cavity-nesting species; i.e., the birds with small beaks not well-adapted for carpentry work on decaying trees.
In contrast, members of the woodpecker family, with beaks designed for wood carving, are do-it-yourselfers and usually disdain a prepared nest box. Most of the nest boxes installed by volunteers in parks are intended for use by swallows (both tree and violet-green) or chickadees (both chestnut-backed and black-capped). Occasionally, red-breasted nuthatches or Bewick’s wrens will use a box designed for chickadees. A few larger boxes have also been installed in some parks for the use of wood ducks and other duck species that nest in boxes.
Nest boxes must be built with the specific needs of various species of birds in mind. Rough unfinished wood, preferably rot-resistant cedar, that mimics the bark on a tree is vastly superior to a painted box. The nest hole must be of a specific size just large enough to allow adult birds to enter but too small for predators such as jays or raccoons. A perch is not only unnecessary but can make it easier for a predator to raid the nest.
As is the case with all real estate, location is key. Swallows are swift flyers and need a clear flight path to the nest hole.
In contrast, chickadees need a selection of small branches not far from the nest hole where they can perch for a few minutes to double-check that no one is watching before they disappear into their box.
It is important nest boxes be located where predators such as cats and raccoons cannot gain easy access. In a backyard, placing a nest box on the side of a house or tool shed is often much safer than putting it in a tree, which, unlike the wall of a building, can be climbed. Swallows, prodigious consumers of mosquitoes, sensibly prefer to nest close to their food source so placing their nest boxes near water is often essential for success. If you or your neighbour has a swimming pool, you might be able to attract swallows to nest in your yard.
Chickadees, in contrast, are forest-dwellers so you will need some trees nearby to appeal to them. It’s a good idea to hang a box where it will get some morning sun and place some wood shavings inside on the bottom. Swallows will add duck feathers to line their nest. In contrast, chickadees like to do a little remodelling and, typically, will remove a few wood shavings and then bring in moss to make a final layer for their eggs.
Because a chickadee nest box is often the best choice for a backyard nest box, the Burke Mountain Naturalists have placed instructions for construction on their website (www.bmn.bc.ca).
It’s a good idea to install a nest box prior to the nesting season, which could start as early as March, because birds like to scout out suitable nesting sites a few weeks before actually selecting one. If you are lucky enough to attract chickadees to nest in your yard, you will be guaranteed many hours of fascinating observations.
Elaine Golds is a Port Moody environmentalist who is vice-president of Burke Mountain Naturalists, chair of the Colony Farm Park Association and past president of the PoMo Ecological Society.