Why such a narrow focus and such a specific audience?
In my work with Bird Studies Canada, a not-for-profit organization dedicated to bird conservation, I have been asked by many—from land trusts to forestry companies—for BMPs for forest birds. Those asking were often surprised when I couldn’t give them a laundry list of BMPs. Surely, with all we know about birds, we must know what habitats they need and how to create or avoid them. Unfortunately, it isn’t that simple.
To start, birds’ habitat preferences can vary widely throughout their range. For example, in southwestern Ontario, the Acadian flycatcher (one of the birds included in the guide) is found in mature hardwood forest, nesting along wooded ravines and in forest swamps. However, in the southernmost part of its range, in Texas, it inhabits conifer-dominated cypress swamps. In addition to occupying different habitats, the bird’s reaction to harvesting differs between regions as well. In Ontario, the Acadian flycatcher is intolerant of any harvesting and needs large tracts of undisturbed forest; in South Carolina, it breeds successfully in heavily managed loblolly pine plantations.
This example is over-simplified, but it demonstrates the need for region-specific BMPs. We don’t necessarily know why birds’ preferences vary by region or what commonalities exist between these different habitats that make them all suitable for Acadian flycatchers. There are pine plantations in southwestern Ontario, but unlike the pine plantations in South Carolina, none of them host Acadian flycatchers. Because we don’t understand why, it is especially important to, whenever possible, use information from local scientific research so we can best predict how birds will respond to changes in habitat and silviculture. In the absence of this information, we need to make our decisions using the best information available and monitor the results closely to ensure desired outcomes.
In the case of the Acadian flycatcher, there are fewer than 40 pairs in Canada, all of which are located in southwestern Ontario. With so few individuals, just a few poor management choices could literally extirpate the Canadian population, making it that much more critical that we proceed with caution. Of course, the solution would also be relatively simple if Acadian flycatcher were the only species we needed to worry about, but that isn’t the case.
Today, woodlot owners and managers face an ever-increasing number of competing priorities, particularly in areas like southern Ontario, where we have high numbers of species at risk – including many species with different, and sometimes conflicting, habitat needs and preferences. What do you do when one species needs a closed canopy forest, while another prefers a more open canopy with large gaps? Or when one species thrives following a moderate cut, and the other can’t tolerate any harvesting?
This is the case in southwestern Ontario, where the Cerulean warbler, another small songbird, and the Acadian flycatcher overlap. The Cerulean warbler nests in mature deciduous forests with canopy gaps. Under the right conditions, some silviculture practices, like a moderate group selection that retains large trees, can result in increased numbers of Ceruleans. Thus, opening up a closed canopy forest could potentially benefit Cerulean warblers. But, as described above, opening a closed canopy forest occupied by Acadian flycatchers will negatively impact them.
Tailoring management recommendations to a specific locality can help identify these conflicts and can provide help to prioritize species and their habitat needs. In this case, mature closed canopy forest, along with the Acadian flycatcher, are higher conservation priorities in southwestern Ontario. This habitat is very rare, and the Acadian flycatcher occurs nowhere else in Canada. The Cerulean warbler, while also rare, has a second and larger population stronghold in the Frontenac region. While we want to maintain both species and their habitats in southwestern Ontario, we also want to be sure that we don’t create Cerulean warbler habitat at the expense of Acadian flycatcher habitat.
Lastly, a good BMP should be easy to understand and to follow. However, biologists may look at and characterize forests differently than forest practitioners, perhaps using different terms or qualifications than a forester would use. Since this guide was written by a biologist, we have made efforts to address this issue by consulting various forest practitioners. We would greatly appreciate further input from owners and managers of small woodlots, as well as tree markers and other forest practitioners.