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Conserve Ontario’s Carolinian Forests: Preserve Songbird Species at Risk

Management Guidelines for Forest Songbird Species at Risk

The Land Manager’s Guide also provides specific management guidelines for individual species, including species at risk. These guidelines will lessen the risk of disturbing or destroying the habitat of these species at risk:

For Acadian Flycatchers, emphasis should be placed on conserving large (at least 25 hectares with preference to forest tracts larger than 100 hectares), mature tracts of forest with little internal disturbance, and maintaining canopy cover in riparian and swamp forest habitat. The highly fragmented landscape and scarcity of large mature forests in southern Ontario limit populations. Restoring and preserving large mature forests not only provides good nesting habitat, but also may alleviate edge effects (e.g., predation and parasitism), increase population size, and facilitate range expansion. This species is tolerant of light selection harvest, but even moderate logging within territories is expected to eliminate populations for years, if not decades, before the habitat is again suitable for this species.

The Cerulean Warbler has become a symbol of healthy, mature deciduous forests. It is rather intolerant of intensive habitat disturbances, but breeds successfully in sites managed for maple syrup. Cerulean Warblers benefit from the protection of mature forests or wilderness areas and management efforts that focus on the production of high quality timber, because they rely on tall, large diameter trees that form full forest canopies. These practices allow for longer rotations, uneven-aged structure, vertical diversity, and tall canopies, while high-grading, diameter-limit cuts and even-aged systems that remove most or all the largest trees are unsuitable practices for maintaining or restoring Cerulean Warbler habitat. Carefully applied group selection cuts may be a good tool, because Cerulean Warblers not only associate with small canopy gaps and internal openings, but they also favour trees such as oak and hickory that are tolerant of moderate shade yet require some light to regenerate and grow.

Hooded Warblers move into woodland gaps one to five years after creation, and remain as long as suitable shrubby nesting habitat exists. Hence, both single-tree and group selection in large (preferably forest tracts larger than 100 hectares), mature forests will benefit this species by promoting dense understory and shrub growth. Managed mature conifer plantations with canopy gaps containing low, deciduous understory species will also be occupied. Despite their dependence on disturbance, Hooded Warblers only require small gaps, and nest more successfully in natural tree fall gaps than those created through intensive forestry. Therefore, emphasis should be placed on conserving large, mature tracts of forest in an effort to remediate the historical loss and fragmentation of woodlands in southern Ontario. Given Hooded Warblers are area-sensitive, efforts to enlarge or reconnect existing forests will further increase populations of this species and assist in their range expansion.

Louisiana Waterthrushes are area-sensitive and require large (preferably forests tracts larger than 100 hectares) contiguous tracts of mature or old-growth forests with shady riverbank or stream habitats. The species is tolerant of light selection harvest, but given its rarity, care should be taken to retain a large number of trees (particularly large trees), and refrain from logging or other activities that increase siltation and water temperature of streams wherever this species is found.

Of the five songbirds discussed in this document, Prothonotary Warblers are most sensitive to forest management activities and thrive in mature forests with no tree cutting. As a specialized, secondary cavity-nesting species that builds its nest largely out of shade tolerant mosses, Prothonotary Warblers are sensitive to all forms of forest management. Retention of large, mature swamp forests in an intact condition, particularly at sites that have a record of historical occupancy is recommended. Increasing the extent and connectivity of swamp forest habitat in southern Ontario is expected to benefit this and numerous other wildlife species.

The complete Land Manager’s Guide and other information on woodland management in southern Ontario can be obtained from the Ontario Ministry of Natural Resources or from the Landowner Resource Centre, 3889 Rideau Valley Drive, Manotick Ontario K4M 1A5. Email: info@lrconline.com.

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