Seabird–wind farm interactions during the breeding season vary within and between years: A case study of lesser black-backed gull Larus fuscus in the UK

Abstract

The marine environment is increasingly pressured from human activities, such as offshore renewable energy developments. Offshore wind farms may pose direct risks to seabirds at protected breeding sites. However, changes in food availability may influence foraging behaviour and habitat use during the breeding season or between years. Consequently, seabird-wind farm interactions, and risks posed to populations, may vary over longer time scales, but this has seldom been quantified. We used GPS-telemetry to study the movements of 25 lesser black-backed gulls from the Alde-Ore Special Protection Area (SPA), UK between 2010 and 2012, while birds were associated with their breeding colony. Variation in movements away from the colony, offshore, and in operational, consented and proposed Offshore Wind Farm Areas ("OWFAs") was investigated: (1) between years and (2) across the breeding season, addressing: (3) sex-specific, (4) individual and (5) diurnal/nocturnal differences. The extent of overlaps with OWFAs varied between years, being greatest in 2010 (7/10 birds showing connectivity; area overlap: 6.2±7.1%; time budget overlap: 4.6±6.2%) and least in 2012. Marine habitats close to the colony were used before breeding. Birds spent little time offshore as incubation commenced, but offshore usage again peaked during the early chick-rearing period, corresponding with use of OWFAs. Individuals differed in their seasonal interactions with OWFAs between years, and males used OWFAs significantly more than females later in the breeding season. This study demonstrates the importance of tracking animals over longer periods, without which impact assessments may incorrectly estimate the magnitude of risks posed to protected populations.

Contrasting effects of GPS device and harness attachment on adult survival of Lesser Black‐backed Gulls Larus fuscus and Great Skuas Stercorarius skua

“…In 2011, GPS devices of the same type and model were attached to a further 14 Lesser Black‐backed Gulls (Thaxter et al . ) and 20 Great Skuas (10 each in Foula and Hoy) using the same wing harness design (Wade et al . ).…”

“…A small piece of neoprene was attached underneath the tag to provide additional comfort for the bird . In 2011, GPS devices of the same type and model were attached to a further 14 Lesser Blackbacked Gulls (Thaxter et al 2015) and 20 Great Skuas (10 each in Foula and Hoy) using the same wing harness design (Wade et al 2014).…”

Development of a tag-attachment method to enable capture of fine- and landscape-scale movement in black-cockatoos

“…UvA-BiTS tags have been used successfully to track marine species such as gulls (Camphuysen et al 2015;Thaxter et al 2015), and raptors (Schlaich et al 2015) and vultures (Donázar et al 2015). Our study was the first to trial UvA-BiTS tags on a cockatoo.…”

Sample size required to characterize area use of tracked seabirds

“…We captured birds at the nest site during early incubation using a walk-in wire mesh trap . During June 2010 and May 2011, we attached solar-powered GPS devices (University of Amsterdam, Amsterdam, Netherlands; Bouten et al 2013) using either a leg-loop harness (n ¼ 3 birds, 2010), a body harness with a breast strap (n ¼ 4 birds, 2010), or a wing harness (n ¼ 4 birds, 2010, 14 birds 2011Thaxter et al 2014Thaxter et al , 2015. The total mass of devices (plus harness) was 21 g (<3% body mass, x weight ¼ 851 AE 85 [SE] g, range ¼ 710-955 g).…”