English: One of the most critical phases in the life of a nesting-burrow petrel is fledging. At this moment, birds have to leave their nests, where they were born and grown, and fly for first time to sea normally at night. Unfortunately thousands of fledglings are disoriented by artificial lights around the world in archipelagos as Hawaii, Azores or Canary Islands. Once birds are grounded they are unable to take off again and susceptible to death by vehicle collisions, starvation, dehydration or predation by introduced predators. To mitigate light pollution-induced mortality rescue campaigns are conducted every fledging season by local governments or NGOs asking for implication of the general public. Thanks to this effort about 90% of rescued birds are successfully released into the wild, giving them a second chance. This Cory's Shearwater Calonectris borealis fledgling picture was taken while researching factors of light pollution-induced mortality in Tenerife, Canary Islands.