Forest Operations Apply Science to Protect Forest Birds
Wednesday, April 23, 2009 – Mattawa, ON - Canadian forests are home to more than 300 species of birds, with an estimated three billion individuals at the start of the spring breeding season. Some of these species stay all year, but most migrate varying distances to spend the winter where more abundant food and warmer temperatures increase their chance for survival. Birds occupy all types of forested and non-forested lands across Canada, with many species requiring specific habitats. As a result, changes in bird abundance are used as one measure of human impact on the environment.
Many species that are in decline live in open non-forested habitats such as grasslands and shorelines where forest operations do not occur. The decline in populations of species such as the Common Nighthawk, Chimney Swift and Tree Swallow may be linked to changes in the availability of insects, which in turn may be related to changes in climate patterns.
What about forest-dwelling birds? A recent study indicates that over the past 20 years, populations of almost 50% of forest-dwelling bird species have increased in Ontario, while the numbers of some 21% declined. Similar trends have been noted nationally. While this is good news, it implies that some species common in Canadian forests continue to decline. This could lead some people to jump to the conclusion that forestry is to blame; however, the causes for population declines are complex and based on multiple factors. These include habitat destruction, expansion and changes in urban and agricultural development, reduced quality of migration habitat, changes in food sources, genetic introgression and possibly climate change. One forest-dwelling species that has declined by about 50% in the last 20 years is the Northern Goshawk. It lives in older boreal conifer forests and its abundance mirrors the rise and fall of populations of its principle prey, the snowshoe hare. However it is not clear whether its abundance is related to habitat supply or the hare cycle.
What efforts are being made to ensure there is sufficient habitat for forest-dwelling birds in Canada? With the importance of Canadian forests to bird populations, habitat requirements are widely considered in forestry activities on public lands across the country. Forest managers purposefully create a mix of different types and ages of forest landscapes to maintain habitat for a wide range of bird species. In many provinces, forest managers use computer models to predict the amount of habitat required for a number of species to ensure an adequate supply over the long term. Within managed forests, a variety of structural features are also maintained to benefit birds. This includes trees with holes and hollows for cavity-nesters, mast-producing trees for nut eaters such as blue jays and nuthatches, and coniferous trees within hardwood forests for nesting sites for species that depend on a mix of tree species like black-throated green warblers. Specific management practices are carried out to ensure that species of special ecological or social concern are protected. For example, unlogged buffer zones are maintained around nests of falcons, eagles, ospreys, herons, hawks, and owls. These examples along with other conservation initiatives are part of the efforts of forest managers to maintain habitats for the numerous species that live within Canadian forests.
The Canadian Institute of Forestry – Institut forestier du Canada (CIF/IFC) is one of Canada’s oldest and most respected forest conservation organizations. The members of the CIF/IFC are concerned about birds and work diligently through government, industry and non-government organizations to assist in the conservation of the birds, which inhabit Canada.
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John F. Pineau 4/22/2009 |
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