Swift Awareness Week: Common Swift

The 27th June to 5th July 2026 is Swift Awareness Week. To mark this, and the 350th anniversary of the publication of Francis Willughby’s Ornithologia, this post focuses on part of the description of the Common Swift in Ornithologia.

Willughby knew this bird by the name of not only the Swift but also the Black Martin and Hirundo apus. The latter name was also the official binomial name given to it by Carl Linnaeus in 1758. However, this was changed to Apus apus following the introduction of the Apus genus in 1777 by the Italian naturalist Giovanni Antonio Scopoli.

Willughby classified this species amongst the Swallows. However, as a result of recent genetic analysis, the Swift is no longer classified with the Swallows and is now classified under the order Apodiformes, which includes Hummingbirds. It is now known that the physical similarities between Swifts and Swallows are a result of convergent evolution not a close genetic relationship.

In Ornithologia, it was commented that the Swift was the biggest of the Swallows that they had hitherto seen. It weighed three-quarters of an ounce (about 21.2g) and its length from the tip of the bill to the end of the claws was 5 inches (12.7cm), whilst to the end of the tail it was 7¼ inches (about 18.4cm). The wingspan was 16½ inches (about 41.2cm).

Common Swift in Francis Willughby's Ornithologia

Its head was large and it had a huge wide mouth but a very small, black bill that was depressed and broad toward the nostrils. The nostrils were long, placed obliquely and an obtuse shape toward the head but acute toward the point of the bill. Its eyes were large and the irises were hazel coloured.

Common Swift, 2025. Photograph taken by Alexis Lours, CC BY-SA 4.0, via Wikimedia Commons.

There was almost no variety of colour in the whole body because the upper as well as the lower side, the wings and the tail were black, with an obscure green or reddish tincture. It was only under the chin that there was a notable spot in a white or ash-grey colour. Willughby commented that they had seen pictures of Swifts that had their whole underside white, specifically the throat, breast and belly. This is probably referring to the genetic condition leucism, which in Swifts is considered rare affecting about 1 in 30,000 birds.

In Ornithologia, it was written that each wing had 18 flight feathers, which ended in a sharp point. The tail had 10 feathers all ending in a sharp point that were, from the middle to the outermost, one longer than next in order.

Its legs were very short but thick and its feet were very small. All of its toes stood forwards, which was notable because the least toe in most species stood backwards, whereas in the Swift it was the same as the rest.

It ate beetles and other insects.

Willughby commented that it was said that due to the reason of the length of its wings and the shortness of its legs, if it happened to fall upon the ground, it was unable to raise itself up again. Thus, it was always either flying or sitting upon the tops of churches, towers or other ancient buildings.

This comment is mostly true. It is true that their legs are tiny, weak and suitable only for clinging to vertical surfaces and in most circumstances, as a result of that, a grounded Swift is unable to raise itself. However, a strong, healthy adult Swift can sometimes manage to launch itself from the ground through the strength in its wings alone but only if it was on a smooth, flat surface. Common Swifts are considered the most aerial bird in the world as they sleep, eat, drink and even mate whilst in the air. They only land in order to breed and normally choose holes in high buildings for this and the only places that they tend to “rest” on are high, vertical surfaces.

Further Reading: John Ray, Francis Willughby's Ornithologia, 1678, p.214, T39.

Author - Debbie Jordan, Middleton Hall Volunteer.

Please consider supporting Middleton Hall Trust by sending us a donation.