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RodrÃguez, A., RodrÃguez, B., Curbelo, Ã. .J., Pérez, A., Marrero, S., Negro, J. J., et al. (2012). Factors affecting mortality of shearwaters stranded by light pollution: Mortality of shearwaters attracted by light pollution. Anim Conserv, 15(5), 519–526.
Abstract: Every year and across the world, thousands of fledglings of different petrel species crash into human structures because they are disorientated by artificial lights during their first flights. As this phenomenon is rather predictable, rescue campaigns are organized to help birds to reach the ocean, but unfortunately, a low proportion gets hurt or dies. Despite the huge number of affected individuals, and the fact that the problem was detected a long time ago, little is known on this source of mortality. We have studied the factors (i.e. body condition, plumage development, fledging date and sex) influencing the mortality of Cory's Shearwater Calonectris diomedea fledglings stranded inland due to light pollution in Tenerife (Canary Islands) during two consecutive breeding seasons (2009 and 2010). Late fledglings showed lower values of a body condition index than early ones. No sex biases were detected, neither considering stranded birds overall, nor for recovery dates or in the body condition of rescued fledglings. Our results indicate that late birds stranded by lights showing abundant down are more susceptible to fatal collisions and that the lights do not selectively kill birds with lower body condition indices. An enhancement of veterinary care should be done during the last part of the fledging period when more fatal collisions occur, especially focused on fledglings with abundant down. More research to determine why some individuals end up disoriented around artificial lights and others do not is urgently needed to minimize or prevent fallouts.
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Rodrigues, P., Aubrecht, C., Gil, A., Longcore, T., & Elvidge, C. (2012). Remote sensing to map influence of light pollution on Cory's shearwater in São Miguel Island, Azores Archipelago. Eur J Wildl Res, 58(1), 147–155.
Abstract: Global economic and population growth increase the extent and intensity of artificial night lighting. From an ecological perspective, this is light pollution, which causes changes in reproductive physiology, migration and foraging of many species and ultimately leads to loss of biodiversity. Some seabirds are intimately linked with the light features of their environments because they are nocturnally active. We report light-induced groundings of Cory’s shearwater (Calonectris diomedea) during a 2-year study (2008 and 2009) in São Miguel Island, in the Azores archipelago, and investigate the spatial correlation of locations of grounded birds with an annual composite of remotely sensed stable lights. Results indicate that 16.7% of fledglings are attracted to lights. The exposure of shearwater colonies in the study area to artificial night lighting is low overall. Four colonies account for 87% of the grounded birds. The distance each bird was found from the closest colony was best explained by the ratio of the satellite-measured light levels at the grounding spot to the light levels at the assigned colony of origin. These results demonstrate that satellite-observed nighttime lights are sufficient to assess risk to marine birds at the scale of oceanic islands and indicate their utility for monitoring the effectiveness of programs to manage lighting to reduce risk for these species and conducting global assessments of species vulnerability. To minimize the impact on Cory’s shearwater and other marine birds, we recommend measures such as reduction and control of lighting intensity near colony locations, while continuing and re-enforcing rescue campaigns.
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Rodríguez, A., García, D., Rodríguez, B., Cardona, E., Parpal, L., & Pons, P. (2015). Artificial lights and seabirds: is light pollution a threat for the threatened Balearic petrels? J. of Ornith., 156(4), 893–902.
Abstract: Petrels are among the most threatened group of birds. On top of facing predation by introduced mammals and incidental bycatch, these seabirds have to deal with an emerging threat, light pollution, which is increasing globally. Fledglings are disoriented and attracted to artificial lights in their maiden night flights from their nests to the sea. Once grounded, they are exposed to multiple threats leading to high mortality. We report on numbers of three petrel species (Balearic shearwater Puffinus mauretanicus, Scopoli's shearwater Calonectris diomedea, and European storm-petrel Hydrobates pelagicus) rescued on the Balearic Islands, Mediterranean Sea, in the period 1999-2013. We assessed the proportion of grounded fledglings in the population and colonies impact based on radiance levels measured from a nocturnal satellite image. We also calculated the radius of light pollution impact. At least 304 fledgling birds were found stranded due to attraction to artificial lights, fatally affecting 8.5 % of them. The proportion of grounded fledglings ranged between 0.13 and 0.56 % of the fledglings produced annually. The body mass of Balearic and Scopoli's shearwater fledglings decreased with rescue date. Light-induced mortality increased during the fledging period for Scopoli's shearwaters. Birds were rescued at a mean distance of 4833 m from the nearest colony, and between 30 and 47 % of colonies were exposed to light-polluted areas. Although impact seems to be low for all species, urban development and, consequently, the increase in light pollution in the proximity of the colonies should be taken into account to reduce as much as possible this emerging source of mortality.
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Rodríguez, A., Rodríguez, B., & Lucas, M. P. (2012). Trends in numbers of petrels attracted to artificial lights suggest population declines in Tenerife, Canary Islands. Ibis, 154(1), 167–172.
Abstract: The secretive breeding behaviour of petrels makes monitoring their breeding populations challenging. To assess population trends of Cory's Shearwater Calonectris diomedea, Bulwer's Petrel Bulweria bulwerii and Macaronesian Shearwater Puffinus baroli in Tenerife from 1990 to 2010, we used data from rescue campaigns that aim to reduce the mortality of fledgling petrels attracted to artificial lights as proxies for trends in breeding population size. Despite increases in human population size and light pollution, the number of rescued fledglings of Cory's Shearwater and Bulwer's Petrel increased and remained stable, respectively, whereas numbers of rescued Macaronesian Shearwaters sharply declined. In the absence of more accurate population estimates, these results suggest a worrying decline in the Macaronesian Shearwater's breeding population.
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