I have a complicated relationship with the lighthouse on Burgess island. I love it for the predictable swing of the beams that slice out into the night, rays reaching out into the dark sea. I try and nab the bunk in the A-frame that looks out over the rest of the island group so I can watch the beams and the fainter flickers of light refracting through the panes skim across the water, a long way below. Its sentinel stance guides me back from my cliff-side study plots to the warmth of the hut at the end of a night’s work. I love the feeling of being perched, poised on top of the island, and the vantage from up by the lighthouse is breathtaking.

But every time I go to Burgess, for a prolonged seabird-science stint or even just a quick day trip, my circuit of the lighthouse reveals broken wings and stiff necks twisted the wrong way, bits of birds caught by those beams. Light at night is a magnet for nocturnal seabirds – particularly young ones, leaving the dark of their burrows for the first time. It baffles them. They hit the lighthouse, and then the ground. Some of them shake it off. Others don’t. I find angel-wing remains of those that the island kāhu have discovered in the dawn – little storm-petrel snacks, white feathers tossed wide into the muhlenbeckia. The broken remains of tītī – Cook’s petrels, or oī – Grey-faced petrels, depending on the season.

We’re studying how different types of light attract seabirds, trying to find ones that have the least impact while still being fit for their purpose – navigational aids still need to be seen from long distances away, deck-lights on ships need to keep their crews safe. But Burgess is becoming more and more of a seabird island as the ecosystem recovers from grazing, soil compaction and the ravages of rats. In the big picture there are greater threats to seabirds than a lighthouse – fisheries bycatch, for example. But it’s just one more obstacle in the path to their recovery – so it’s worth thinking about. And constantly seeing the impacts first-hand makes me think about it rather a lot.