|Forest Investment Account (FIA) - Land Base Investment Program|
|FIA Project 6859002|
|Breeding Success of the goshawk (A. g. laingi) on Haida Gwaii, 2009|
|Subject: Forest Investment Account (FIA) - Land Base Investment Program|
|Series: Forest Investment Account (FIA) - Land Base Investment Program|
|This was fifteenth year of goshawk inventory and research, and the tenth year of systematic goshawk nest monitoring on Haida Gwaii. Nest monitoring included several visits to each known breeding area. If no birds were initially located, goshawk playback surveys were conducted throughout the breeding area and in adjacent areas of suitable habitat (within ~ <2km of the known breeding area), to establish if the birds were present and possibly using an alternate nest. |
All 15 of the previously known breeding areas were monitored. Birds were detected in 2 (13%) of 15 Breeding Areas during the breeding season, but young (2) only fledged from the one site (Bonanza).
However, analysis of the results from intensive spring and summer monitoring of seven breeding areas indicates that until recently (<2007) birds were present in many breeding areas (as determined by the presence of any fresh sign or birds within the breeding area). We don't know if these are/were necessarily different birds within each area, but it does indicate that birds are/were still persisting in many breeding areas, even though annually very few of the areas appear to regularly fledge young. This very low rate of breeding success (breeding areas fledging young), is still of great concern as to its negative implications to the long-term viability of the goshawks on Haida Gwaii, and has previously been linked to the impacts of introduced deer, past extensive clear-cut harvest practices, and potentially also in part to a changing climate.
Comparative analysis, of the area of medium-high suitability foraging habitat at the predicted territory scale, supports earlier reports that indicates that the most (~80%) territories on Haida Gwaii have 50-60% of medium-high suitable habitat (mature-old growth). However, above this potential threshold, breeding success (fledging young) does not appear to increase with the area of medium-high suitable habitat, and may in part be tied to the area of edge habitat (interface between mature-old growth and recently harvested and natural openings); a habitat which on Haida Gwaii may provide increased foraging opportunities.
To ensure the forest stewardship goals for goshawks continue to be met in the context of all these potential changes, it is recommended that the long-term monitoring of goshawk Breeding Areas continues. No other forest dependent species on Haida Gwaii has been so closely monitored throughout this period of change, and continued monitoring therefore provides the only opportunity to determine which areas on the island will continue to support goshawks. This monitoring should therefore continue to be linked by adaptive management feedback loop to all forest stewardship managers, and to the goshawk Recovery Team, such that we can continue to identify, and manage for nesting and foraging conditions that support goshawks.
|Contact: Frank Doyle, (250) 846-5100, firstname.lastname@example.org|
Updated August 16, 2010
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