Seabird displacement at the Bligh Bank offshore wind farm N. Vanermen, T. Onkelinx, W. Courtens, M. Van de walle, H. Verstraete & E.W.M. Stienen IMCC, Glasgow 16 August 2014

Seabirds and offshore wind farms 2 Barrier to migration & local flight movements Habitat change Increased mortality due to collision fatalities

Seabirds and offshore wind farms 3 Habitat change Attraction? Avoidance?

Monitoring seabird displacement 4 Ship-based seabird surveys according to the internationally applied ESAS methodology (Tasker, 1984)

Monitoring displacement effects: BACI set-up 5 control impact Before After

Monitoring displacement effects: monitoring route 6

Monitoring displacement effects: data modeling 7 Statistical challenges inherent to ‘seabirds at sea’ data Auto-correlation in time and space > aggregation of transect data to day totals per control/impact area Overdispersion > use of a negative binomial distribution High proportion of zero counts > accounting for zero-inflation ZINB modelling

Monitoring displacement effects: data modeling 8 Seasonal variation modelled by a cyclic sine curve: Little gull ( 12 month period  2 degrees of freedom )

Monitoring displacement effects: data modeling 9 Seasonal variation modelled by a cyclic sine curve: Razorbill ( 12 month period  2 degrees of freedom )

Monitoring displacement effects: data modeling 10 Seasonal variation modelled by the sum of 2 cyclic sine curves: Black-legged kittiwake ( month period  4 degrees of freedom )

Monitoring displacement effects: results Bligh Bank 11

Monitoring displacement effects: results Bligh Bank 12

Monitoring displacement effects: results Bligh Bank 13 SIGNIFICANT AVOIDANCE EFFECTS -85% -71%-64%

Monitoring displacement effects: results Bligh Bank 14 SIGNIFICANT ATTRACTION EFFECTS x 9,5x 5,3

Observed attraction effects: ecological incentives?? 15 Roosting possibilities (!)Food availability (?)

16 to like… …or not to like? Observed attraction effects:

17 Observed attraction effects: THANK YOU FOR YOUR ATTENTION! Any questions?