|Forest Investment Account (FIA) - Land Base Investment Program|
|FIA Project 8009005|
|Goshawk Nest Monitoring in the Kispiox Forest District 2009|
|Project lead: Cranberry/Kispiox FIA Steering Committee|
|Subject: Forest Investment Account (FIA) - Land Base Investment Program|
|Series: Forest Investment Account (FIA) - Land Base Investment Program|
|This was the 14th year of goshawk Nest Monitoring in the Cranberry and Kispiox Watersheds. This data set provides us with a unique record of the annual breeding success of a species that has been identified as a focal indicator of how well we are managing our forest ecosystem through the application of "Coarse Filter" management practices (goshawks are dependent on the abundance and availability of forest birds and mammals as prey). Since 1999, in addition to the overall status of the population, monitoring has also been designed to determine the impact of harvesting within nest areas, on the continued use and breeding success of goshawks using these areas.|
Goshawk nest areas were surveyed for the presence of breeding birds at the nestling and fledgling stages, both by looking for sign (active nests, feathers, whitewash, etc,) and by the use of standardized call playback techniques. In those nest areas where sign, and/or birds were seen, follow up surveys were conducted to determine if the birds were breeding.
A total of 22 nest areas were monitored, 11 control sites (no harvesting within the Nest Area) and 11 treatment sites (harvesting had taken place within the nest area). Goshawks were found in only 2 nest areas (1 control sites, 1 treatment), and only the 1 control site fledged young. Collectively this was the lowest rate of nest area reoccupancy and fledging success we have ever observed.
The number of occupied nest areas has continued to decline, and this same trend was also observed several hundred kilometres away in the Nadina Forest District. This indicates that whatever is impacting breeding is occurring at a large regional scale. At this regional scale, the Kispiox and Nadina Districts have very different habitats and harvest histories, suggesting that harvesting, or the associated changes in prey abundance and availability, are unlikely to be the only focal driver behind the regional trend in nest area reoccupancy. Previous analysis has identified both a potential link with changing weather patterns, and or with the abundance of snowshoe hares and grouse which may be focal prey of goshawks in winter. Snowshoe hare populations are cyclic, and numbers are low now but will increase 5-7 fold in the next few years. Continued monitoring of goshawk nest area occupancy and breeding success, through the increase phase in hare numbers will allow us the opportunity to understand the link (if any) between the abundance of snowshoe hares and breeding success of goshawks in our landscape.
In the context of climate change, continuation of the goshawk nest monitoring should also include visits to the nests in summer to determine the impacts of blackflies on the health of the nestlings, as there is concern that altered timing of blackfly hatch dates and/or overall blackfly abundance as a result of a changing climate may significantly affect goshawk nestling survival. This, when combined with information on weather, diet, and breeding success will provide not only insights into how present day landscape management practices are impacting the status of these birds, but also how their status and potentially that of the ecosystems on which they rely, are also being impacted by a changing climate.
|Contact: Frank Doyle, (250) 846-5100, email@example.com|
Updated August 16, 2010
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