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Final Report Summary - ECOLIGHTSFORSEABIRDS (Artificial night lights and seabirds: solutions to a fatal attraction)

Background
The electrical energy conversion into artificial light has brought significant progress to humanity, and the extent and intensity of artificial lighting have increased at an astonishing rate around the world. This alteration of natural light levels in the outdoor environment owing to artificial light sources has been labelled as light pollution. Despite the booming in the usage of artificial lighting, our knowledge of the potential negative effects that can pose for nature and human health is scant. Light pollution has been suggested to have an important impact on ecosystems, inducing physiological and behavioural changes in animals, as well as mass mortality episodes for certain species. Disentangling the implications of light pollution distress is crucial to reduce mortality or detrimental effects on behaviour for nocturnal species and threatened populations of different taxa.
Every year thousands of petrel fledglings are attracted to artificial lights during their maiden flights from their natal nests to the ocean, causing high mortality worldwide. Thanks to rescue campaigns, the bulk of the rescued birds (more than 90%) are rehabilitated and released back to the wild. In addition, some seabirds are an important attraction for ecotourism. Currently, several beaches are artificially illuminated for watching the emergence of little penguins from sea to burrows, which generates important economic resources for conservation and management of wildlife. Although it seems that no direct mortality events occur, long-term effects of artificial illumination on the physiology and behaviour of penguins have not been investigated.

Research objectives
We aim to find solutions to the fatal attraction of seabirds to artificial lights. Specifically, we would like to determine the effect of different types of artificial lights on the on the physiology and behaviour of birds which can ultimately affect their survival. This information can assist to reduce the massive mortality events of petrel fledglings stranded by lights as well as other more subtle potentially negative effects produced by illuminated areas. Given that possible solutions emerging from this research may minimize but not entirely eliminate the problem, we will also assess management techniques during rescue campaigns to further improve the survival rates of affected birds.

Description of work performed
We have analysed three long-term datasets on records of birds grounded by lights or penguin attendance to breeding colonies recorded by automated monitoring systems. In addition, we have conducted three experiments on shearwaters and penguins. In the first one, we tested the effect of different light types (metal halide, and high pressure sodium and LED) in the number of attracted and grounded shearwaters. While in the second and third ones, we have tested the effect of light intensity and light colour on the penguin behaviour at attendance to the colony. Finally, we have conducted fieldwork in Australia and Canary Islands to study the flight characteristics of shearwaters over the lit areas and the body condition and plumage maturation of rescued birds at programs.

Main results achieved so far
We have provided scientific-based information crucial for a better understanding of the light-induced mortality of petrels in two archipelagos: Phillip Island, Australia, and Balearic Islands, Spain. On Phillip Island, we found that mortality of rescued fledglings was 4–8 times higher than that reported elsewhere for other shearwater species, presumably because of the systematic and labour-intensive rescue effort conducted there. This result led us to believe that light-induced mortality of seabirds has been usually underestimated. Furthermore, we demonstrated that reduction of light pollution and better traffic management (speed limit reduction, traffic stopping and display of warning signals) can mitigate artificial light-induced mortality [1]. On the Balearic Islands, we made the first assessment of light-induced mortality in three petrel species, including the most threatened European seabird, the Balearic shearwater, and evaluated light pollution levels on colonies from nocturnal satellite imagery. The proportion of fledglings affected by lights was low, probably due to the coastal distribution of the breeding colonies, although our estimates should be treated as minimum numbers. Between 30 and 47 % of colonies were exposed to high light-pollution levels in a radius of 4 km [2]. We tracked the inaugural flights of shearwater fledglings, offering accurate information on the flight characteristics from colonies to grounding locations (distances and timing). On the Canaries, birds were grounded on the first lit areas found in their pathways to the ocean, and interestingly, birds hatched on inland colonies got a higher probability of being grounded by lights than fledglings from seaward coastal colonies [3]. On Phillip Island, Australia, we studied the body condition of shearwaters grounded by lights (on roads) in comparison with birds on the colonies and washed-out onto beaches. Birds collected on the roads have a better condition than beach-washed birds and similar to birds on the colonies, which means that rescue of grounded birds on roads is worthy as a management and conservation tool [4]. We have studied the attendance pattern of little penguins to two breeding colonies under different lighting conditions: natural night skylight and artificial lights used to enhance penguin viewing for ecotourism. Moonlight could be overridden by artificial light at our artificially lit colony, but the similar patterns between colonies suggest that artificial light did not mask the moonlight effect [5]. Finally, we have led a global review of light-induced mortality on seabirds in collaboration with 27 researchers from around the world. This study highlights the mortality rates caused by artificial lights for some petrel species and it will be a benchmark contribution to the issue [6].

Expected final results, impact and use
We have produced crucial information about the process of light attraction of petrels, for the design of public street lighting on islands where seabirds and humans coexist and artificial lighting used to enhance nocturnal wildlife watching. Briefly, birds grounded by lights are coming from the closest colonies, have a similar condition to those reaching the ocean successfully, and have a higher chance to die with time exposed on the road, traffic intensity and speed limits. We have also demonstrated that metal halide multiplied the mortality risk by 1.6 and 1.9 points in comparison with light emitting diode (LEDs) and high pressure sodium lights. Thus, high pressure sodium lights should be used in areas where light-induced mortality of petrels needs to be reduced [7]. We have experimentally tested that artificial lighting has not a significant impact on the attendance pattern of little penguin to the colony. However, lighting should be minimised to avoid modifying natural light levels as other potential effects may arise.

Project Website: http://ecolightsforseabirds.weebly.com/

Related information

Reported by

AGENCIA ESTATAL CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Spain

Subjects

Life Sciences
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