Abstract
The Animal and Plant Health Agency (APHA) was commissioned by the Institute of Estuarine and Coastal Studies, on behalf of E.ON Humber Gateway Limited, to monitor the 2015 autumn passage and flight activity associated with migrating Pink-footed geese through the Humber Gateway Wind Farm and to compare this data with pre-construction data from a comparable 2012 study.
A bird detecting radar unit was sited near Southfield Farm along Spurn Road, Kilnsea (grid reference: TA416155) and the range was set to include the whole of the Humber Gateway Wind Farm development footprint.
Continuous radar surveys to cover the autumn migration period were carried out between 14 September and 20 November 2015 (68 days). The surveys were combined with visual observations undertaken by radar ornithologists for 7 hours each day, during daylight hours, providing a total of 476 observational hours.
Data was collected for Pink-footed geese exclusively. A total of 312 goose tracks were detected by radar, of which 117 were matched with visual observations (groundtruthed). Information on flight altitude was collected for 105 flocks.
The 117 goose tracks that were groundtruthed accounted for 5159 Pink-footed geese. The mean flock size was 45.1 birds (range 2-200).
Movements of Pink-footed geese occurred in two main peaks: 25-27 September (63 tracks) and 31 October – 21 November (230 tracks).
Pink-footed goose daily activity was fairly evenly distributed with peak movements between 10:00 and 20:00 GMT.
The majority of geese were recorded flying offshore (282 tracks), with only 30 tracks recorded inland.
There were fewer goose tracks within the wind farm footprint than in the pre-construction 2012 study (2.6% in 2015, compared to 11.2% in 2012). This could indicate avoidance of the wind farm.
Eight goose tracks occurred within the wind farm footprint. Of these, only one flock was recorded as having a flight altitude within the rotor-swept zone (24-136 m) and two flocks were visually observed to gain altitude on approaching the wind farm and to fly above the turbines. Altitude data was not obtainable for the remaining five of the goose tracks detected as occurring within the wind farm footprint.
Of the goose flocks with associated altitude data, 48.6% flew within the rotor-swept zone, but only one of these was within the wind farm footprint.
Compared with data from 2012, goose flocks flew significantly closer to the coast and further from the wind farm footprint, which could indicate avoidance behaviour. This is consistent with the results of other, similar radar studies of Pink-footed geese at other wind farms (Plonczkier & Simms, 2012a).