Ona and Husøya boast a rich birdlife, with a remarkable 244 bird species observed on the islands. Their relatively isolated location on the outer coast makes Ona and Husøya some of the best places in Norway to spot rare bird species. The islands act as an oasis for birds in areas with few other landing options. Here, weary birds find a crucial opportunity to rest, feed, and seek shelter from storms before continuing their journey. The lighthouses likely help guide the birds to the islands in the dark. Additionally, Ona and Husøya feature diverse habitats, including tidal areas, gardens, shrubs, fallow agricultural landscapes, and spruce tree zones, which attract a wide variety of species. The islands are very small, concentrating the birds in a limited area, making them easier for birdwatchers to spot. Common species include the black guillemot, kittiwake, greylag goose, meadow pipit, rock pipit, house sparrow, European shag, grey heron, eider, white-tailed eagle, raven, oystercatcher, curlew, white wagtail, barn swallow, twite, and common snipe.