Forest Investment Account (FIA) - Land Base Investment Program
FIA Project 6729003

    Goshawk Monitoring
 
Project lead: Hamilton, Dave (BC Timber Sales)
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Land Base Investment Program
Description:
The coastal subspecies of Northern Goshawk, sometimes referred to as the "Queen Charlotte Goshawk" (Accipiter gentilis laingi), is an uncommon forest raptor that is currently on the British Columbia Red-list as a candidate species for Endangered or Threatened status. It is also an Identified Wildlife Management Species under the BC Forest and Range Practices Act. Federally, A. G. Laingi is designated as Threatened by the Committee on the Status of Endangered Wildlife in Canada. Population trends of this subspecies are unknown in British Columbia, but the subspecies was listed due to its estimated small population size (<1000 mature individuals) and threats to populations from forest harvesting.

In TSA 37, 16 nest trees in 9 confirmed breeding territories (Artlish River, Bear Lake, Elbow Creek, Goose Creek, Lower Stella Lake, Paterson Lake, Pye Lake, Roberts Creek and Surprise Lake) were located between 1994-2002 by BC Ministry of Environment surveys. In 2008, Manning, Cooper and Associates Ltd. Was contracted to monitor these nine goshawk territories to determine their current activity status.

Between 11-23 June and 10-25 July 2008, surveys to determine the breeding activity (nest territory occupancy and nest productivity) were conducted. All known territories were visited at least twice during the survey period: once during the nestling period (11-23 June) and again during the fledgling period (10-25 July). Crews attempted to survey the Artlish River territory in June; however, a landslide blocked all ground/road access for that month. Consequently, the Artlish River territory was only monitored once in July 2008. All surveys followed Resource Inventory Standards Committee standards for raptor surveys, and consisted mainly of call playback and nest search surveys.

A total of 79 call playback stations were completed during the survey period in 2008. Estimated hours surveyed in each known nest territory ranged from 3.0-13.0 hrs, depending on the size of the area surveyed and whether or not there were any previous indications of occupancy. Total crew hours spent conducting goshawk surveys was approximately 72.5 hrs.

Two out of nine monitored territories (Bear Lake and Surprise Lake) in TSA 37 had goshawk detections during 2008 surveys. Goshawk detections resulted in active nests being found in both of these territories. Bear Lake territory produced two young, while Surprise Lake territory produced one young in 2008. The nine monitored goshawk nest territories in TSA 37 had an occupancy rate of 22.2% in 2008. Including the 2008 surveys, there are now 17 known nest trees in nine confirmed goshawk nest territories in TSA 37. Only one new nest was found during surveys in 2008, Surprise Lake Nest #3.

Two other raptor species, Osprey and Red-tailed Hawk were detected during goshawk surveys in TSA 37 in 2008. Two Ospreys (thought to be young of the year) were observed soaring high above the canopy in Lower Stella Lake territory. A single Osprey was observed flying above Surprise Lake Nest #3 in July; an Osprey nest was subsequently found 125 m south of goshawk Nest #3. Although it was not confirmed, this Osprey nest was thought to be active in 2008, suggesting that the goshawk and Osprey had simultaneously active nests in the same general nest stand. A Red-tailed Hawk had an active cliff nest in Strathcona Provincial Park, >1 km from Elbow Creek goshawk Nest #1.

Known goshawk nest territories were monitored in three other study areas on northern Vancouver Island in 2008: two provincial parks (Gold Muchalat and Strathcona); Western Forest Products (WFP) Timber Farm License (TFL) 19; and WFP TFL 37. The two provincial parks had 2 of 3 (66.7%) goshawk nest territories occupied, TFL 19 (near Gold River) had 1 of 6 (16.7%) known goshawk nest territories occupied, and WFP TFL 37 (near Woss) had 6 of 12 (50.0%) known goshawk nest territories occupied in 2008. The mean occupancy for the four study areas was 38.9% in 2008. The occupancy rate for TSA 37 (22.2%) was the second lowest among the four study areas and was lower than the mean occupancy for the four study areas.

Nest productivity in other monitored study areas on northern Vancouver Island in 2008 was 2.8 fledglings/active territory in TFL 37 (Woss), and 2.0 fledglings/active territory in both TFL 19 (Gold River) and in Gold Muchalat and Strathcona Provincial Parks. Mean productivity among the four study areas was 2.1 fledglings/active territory; productivity for TSA 37 (1.5 fledglings/active territory) was lower than the 2008 average, however, nest productivity data should be interpreted cautiously for TSA 37 due to the small samples size for the study area.
Contact: Hamilton, Dave, (250) 286-9346, dave.hamilton@gov.bc.ca

Updated August 16, 2010 

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