Blinded by the light

In summer, the warm evening air rings with the strange but instantly recognisable calls of hundreds of Cory’s Shearwater (Calonectris borealis) nesting in the crevices of the cliffs lining the islands coastline. The calls are usually amongst parents locating one another after an entire day out on the ocean in search of food for their growing chicks. One of the parents leaves the nest the entire day to forage on the ocean while the other remains in the nest tending to the chick, waiting for its partners return after nightfall. Once the chick has grown big and strong enough both parents leave the nest and never return to their young again. Now it is the young birds time to leave the nest.

The fledging of young birds is probably the most risky and deadly operation of their entire lives. One of the worst but most unexpected causes of mortalities in fledging seabirds worldwide, particularly those who are nocturnally active, is light pollution. Like turtle hatchlings fledging Cory chicks typically exit their nests at night or early in the morning, a time when predation from other larger birds is low and natural light is very poor. In the process, the youngsters may be attracted to artificial light sources along the coastline luring them away from their intended destination, the ocean. As they approach the light source the light absorbing protein in their eye, an essential physiological adaption for nocturnal birds, causes them to get blinded by the light and disorientated, often sending the animals crashing into coastal infrastructure.

Apart from plastic pollution and invasive species, light pollution is one of the main causes of death in bird species belonging to the vulnerable Tubenose order (Procellariiformes). This fact prompted  SPEA, the Portuguese society for the study of birds, to set up a nationwide initiative called LuMinAves. The project is dedicated to minimising light pollution and improving data collection, awareness and the effectiveness of volunteer campaigns. Here, experts argue that minimising the use of urban lights will not only help protect several bird species but also reduce electricity expenses and help against climate change.

So what can we do? Well, although such incidents often have fatal consequences for the young chicks, several birds can also be rescued or restored back to health. One part of the LuMinAves project is to offer workshops to show people what to do when they find a lost Cory. Last year, the Lobosonda team released no less than three Cory chicks that were found afraid and disorientated but thankfully unharmed, in the ladies toilet in the marina. 

When you find a disorientated Cory place it carefully into a cardboard box with holes punctured in the sides so the animal gets enough air. Some of the animals can be quite snappy so it also helps to cover the animals head with a cloth to avoid getting injured by their powerful beak. If the bird hasn’t got any visible injuries you can release it on a sheltered rocky beach where it will eventually find its own way to the ocean. If the animal is injured or you are in doubt of your actions, we suggest you contact SPEA on +351 967 232 195.

The time for the fledging of Cory chicks in Madeira is usually during the month of November, one month before the prime time of artificial light pollution; Christmas. So if you want to enjoy a lit-up festive season, abstain from the overuse of Christmas lights for the sake of the young Cory’s and your electricity bills.

By Paula Thake