Behavioural and environmental correlates of soaring‐bird mortality at on‐shore wind turbines

Abstract

Summary 1.Wind power plants represent a risk of bird mortality, but the effects are still poorly quantified. We measured bird mortality, analysed the factors that led birds to fly close to turbines, and proposed mitigation measures at two wind farms installed in the Straits of Gibraltar, one of the most important migration bottlenecks between Europe and Africa. 2. Bird corpses were surveyed along turbine lines and an associated power line to estimate mortality rates. The behaviour of birds observed within 250 m of turbines was also recorded as a putative indicator of risk. The effects of location, weather and flight behaviour on risk situations (passes within 5 m of turbines) were analysed using generalized linear modelling (GLM). 3. Mortality caused by turbines was higher than that caused by the power line. Losses involved mainly resident species, mostly griffon vultures Gyps fulvus (0·15 individuals turbine − 1 year − 1 ) and common kestrels Falco tinnunculus (0·19 individuals turbine. Mortalities were not associated with either structural attributes of wind farms or visibility. 4. Vulture collisions occurred in autumn-winter and were aggregated at two turbine lines where risks of collisions were greatest. The absence of thermals in winter forced vultures to use slopes for lift, the most likely mechanism influencing both their exposure to turbines and mortality. 5. Kestrel deaths occurred during the annual peak of abundance in summer. Carcasses were concentrated in the open habitats around a single wind farm and risk may have resulted from hunting habitat preferences. 6. Synthesis and applications . We conclude that bird vulnerability and mortality at wind power facilities reflect a combination of site-specific (wind-relief interaction), speciesspecific and seasonal factors. Despite the large number of migrating birds in the study area, most follow routes that are displaced from the facilities. Consequently, only a small fraction of birds on migratory flights was actually exposed to turbines. New wind installations must be preceded by detailed behavioural observation of soaring birds as well as careful mapping of migration routes.

Bird Collisions in a Railway Crossing a Wetland of International Importance (Sado Estuary, Portugal)

“…To collect baseline information for mitigating impacts, bird collision risk has been the subject of intensive research over the past two decades (Loss et al 2015), with many studies documenting bird mortality and its correlates in relation to roads (Santos et al 2016), wind farms (Barrios and Rodríguez 2004;Drewitt and Langston 2006), power lines (Barrientos et al 2011(Barrientos et al , 2012, and buildings (Loss et al 2015). Surprisingly, however, very few studies have analyzed bird collision in relation to railways, although these linear infrastructures extend over tens of thousands of kilometers across the world (see Chap.…”

“…Although the population-level consequences of such mortality are poorly known (but see, e.g., Carrete et al 2009;Borda-de-Água et al 2014), it is generally recognized under the precautionary principle that efforts should be made to reduce the number of birds killed each year as much as possible (Loss et al 2015). Information is thus needed on the bird species most vulnerable to collisions, and on the environmental and species-specific factors affecting such vulnerability (Barrios and Rodríguez 2004;Santos et al 2016), which are essential for developing management guidelines aimed at reducing collision risk (Barrientos et al 2011;May et al 2015).…”

Two decades of cumulative impacts to survivorship of endangered California condors in California

“…The difference in utility line related mortality in these populations is presumably the result of fewer utility lines surrounding the Arizona and Baja release sites. While the risk of utility line collision and/or electrocution related mortality has decreased substantially within the current condor range as a result of targeted mitigation efforts, this mortality factor may pose an increased threat to the population in the future as individuals expand their range and reoccupy areas of their historic range, which includes locations of existing and proposed energy developments with transmission lines (Barrios and Rodriguez, 2004;Carette and Sanchez-Zapata, 2010;Telleria, 2009).…”

Composição e dinâmica da avifauna da usina eólica da praia da Pedra do Sal, Delta do Parnaíba, Piauí, Brasil

“…Além das aves de grande porte, as espécies de hábitos noturnos ou que voam nas primeiras e últimas horas do dia possuem maior risco de colisão contra os aerogeradores (NWCC, 2000;Hunt, 2002;Larsen & Clausen, 2002;Langston & Pullan, 2002;Barrios & Rodriguez, 2004). Aliado a isso, é de relevante importância considerar os impactos cumulativos causados pela presença de vários parques eólicos numa mesma região (Langston & Pullan, 2002), e aqueles oriundos da perda de habitat natural decorrente da implantação das estradas de acesso e linhas de transmissão (Saidur et al, 2011).…”