| Migratory summer species. Many people mistake swifts for house martins or swallows. Seen from a distance they appear jet black (martins and swallows have white or creamy bellies, depending on the species) and their wings are highly curved, thin and pointed (while martins and swallows have wider, straighter wings). They arrive at the start of April and leave in August. They thus live with us in Barcelona for just over four months. This period encompasses their breeding cycle, unique in the animal world: common swift pairs mate in the air and juveniles, after taking-off for the first time, neither touch the ground, walls nor roofs for 21 months, by which time they are fertile. They build their simple nests using feathers and twigs glued together with their saliva. They nest in holes in walls or under the tiles of old roofs. They often fly in groups, dashing the blue sky with their outlines. Their long, high-pitched whistle is one of the most representative songs of our summer. |
