![light logger bird light logger bird](https://static.wikia.nocookie.net/rio/images/9/9e/Blu_banner.png)
The majority of our knowledge about the fallout comes from observational data from rescue campaigns and mainly consists of the reporting of species identification, individual numbers, date and location 24, 25, 26. Around 10% of birds collected in the campaigns die, although light-induced mortality could be higher as lay people do not report on dead birds, thus 40% is a more accurate estimate 22.īecause the study of petrels breeding on oceanic islands is challenging (they usually nest in underground burrows on remote, isolated and inaccessible areas, visit the colonies at night and spend most of their time at sea 23), why petrels become disorientated by lights is far from being fully understood. To mitigate light-induced mortality, rescue campaigns are conducted by local governments and NGOs, releasing into the ocean a high proportion of the rescued birds. Every fledging season on islands where humans and petrels coexist, thousands of fledglings of different species are grounded by light pollution, a phenomenon called “fallout” 15, being exposed to injuries or death by collision with human structures or vehicles, as well as predation 16, 17, 18, 19, 20, 21. More than 40 burrow-nesting petrel species, some of them critically endangered, are affected by lights (authors’ unpublished data). For a long time, it has been known that petrel fledglings are attracted and disorientated by artificial lights when they are leaving their nests for the first time and fly towards the sea 14. They also suffer from mass mortality episodes caused by artificial lights. Petrels (Order Procellariiformes) are one of the most endangered groups of birds with commercial fisheries and introduced predators as their main threats 13. From a conservation point of view, mass mortality events of organisms are one of the most severe ecological consequences of light pollution, involving a wide range of taxa such as moths, sea turtles, passerine birds and seabirds 6, 7, 8, 9, 10, 11, 12.
![light logger bird light logger bird](https://global.canon/en/environment/bird-branch/how-to-photograph-birds/lesson22/img/howto22-main-illust-en.png)
Despite the numerous studies and reviews of the field, the underlying factors are far from being understood 5, especially for secretive species. Recently, light pollution has been recognised as an important threat to biodiversity conservation because it can cause cascading effects on ecosystem functioning in several ways 3, 4, 5. Night sky degradation continues as light pollution levels increase at an annual rate of 6% 2. More than two-thirds of the world human population lives under a light-polluted night sky and the alteration of light levels at night hinders the visibility of the Milky Way by more than one-fifth 1. We also offer methodological approaches useful for other critically threatened petrel species grounded by light pollution.Īrtificial lights have provided important benefits to humanity, but they have also led to a loss of the natural nightscapes worldwide. We provide scientific-based information to manage dark refuges facilitating that fledglings from inland colonies reach the sea successfully. Breeding habitat alteration by light pollution was more severe for inland colonies. Rescue locations showed radiance values greater than colonies and flight distance was positively related to light pollution levels. Most birds left the nests in the first three hours after sunset. Birds were grounded at locations closer than 16 km from colonies in their maiden flights and 50% were rescued within a 3 km radius from the nest-site.
![light logger bird light logger bird](https://imagesvc.meredithcorp.io/v3/mm/image?url=https%3A%2F%2Fstatic.onecms.io%2Fwp-content%2Fuploads%2Fsites%2F28%2F2019%2F07%2Fseagull-bird-curry-exotic-CURRYBIRD0719.jpg)
We used GPS data-loggers to track the flights of Cory’s shearwater Calonectris diomedea fledglings from nest-burrows to ground and to evaluate the light pollution levels of overflown areas on Tenerife, Canary Islands, using nocturnal, high-resolution satellite imagery. Seabird fledglings are attracted by artificial lights when they leave their nest at night, causing high mortality. Knowledge on the threshold levels of light pollution at which significant ecological impacts emerge and the size of dark refuges to maintain natural nocturnal processes is crucial to mitigate its negative consequences. Light pollution and its consequences on ecosystems are increasing worldwide.