Common Swift (Apus apus)
This bird is such an accomplished flier it has earned the
adjective “Swift” as its common name and Apus
apus , greek for “no foot” as its scientific one, since it does not land
from the day it fledges. It is often confused with the swallow but is in fact
completely unrelated, being closer to nightjars and owls *and so are a great example of
convergent evolution. Not to mention the
swallow’s aerial abilities pale in comparison. No self-respecting swift would
be seen perching on a telephone line. They eat, drink, sleep and mate in the skies,
spending most of their life far above in the open air but also moving at
incredible speed kamakazi-style between
buildings and other obstacles ( I even witnessed one vertically-slaloming
telephone wires!) . They are the peak of avian adaptation to the skies. Healthy
adult swifts are so un-catchable they only have two predators in the British
Isles, both falcons; The hobby Falco
subbuteo, swift-like in itself and a famed dragonfly catcher, and the
peregrine Falco peregrinus, which
includes swifts as a significant part of its diet in urban areas1. For
some footage of a hobby catching a swift, see this video. The catch is at
04:15.
The swift’s body is well adapted for life on the wing, with stiff sickle-shaped wings making them resemble little, dark aeroplanes and forked tails giving them great steering. Their wide mouths simply scoop up the ‘aerial plankton’ of tiny flies, beetles, wasps, aphids, thrips and money spiders ᵻ as they speed along. They do have tiny feet which tuck under their feathers like a plane’s undercarriage, but with sharp curved claws for gripping onto the vertical surfaces such as walls and cliffs where they nest. Their four toes are oriented with one pair facing forward and the other backward(known as zygodactyly), a feature which they share with their hummingbird, nightjar, and owl relatives.
The swift’s body is well adapted for life on the wing, with stiff sickle-shaped wings making them resemble little, dark aeroplanes and forked tails giving them great steering. Their wide mouths simply scoop up the ‘aerial plankton’ of tiny flies, beetles, wasps, aphids, thrips and money spiders ᵻ as they speed along. They do have tiny feet which tuck under their feathers like a plane’s undercarriage, but with sharp curved claws for gripping onto the vertical surfaces such as walls and cliffs where they nest. Their four toes are oriented with one pair facing forward and the other backward(known as zygodactyly), a feature which they share with their hummingbird, nightjar, and owl relatives.
As a late migrant to Britain, the coming of swifts (for me at
least) epitomises the summer. The
screeching of males in high-speed chase of a female and their mass flocks
around gluts of insects like flying ants are familiar sights and easily
observable in urban areas where they temporarily fill the skies with activity.
You might think that such a master of the air, which has adapted
to our urban habitats, would be unaffected by people. Unfortunately the swift’s
Achilles heel is the need to nest in high, inaccessible crevices which are
decreasing as old buildings are levelled or repaired, whilst new buildings
often have no suitable nest sites. Coupled with this are the unknown problems
in Africa facing many of our summer migrants, perhaps caused by climate change.
You can help solve the former problem simply by installing a ‘swift box’ on
your property, which can be bought or made from instructions which are
available online. In addition, try and encourage authorities to install them on existing and/or planned
buildings in your area. Whatever you do, be sure to visit Swift Conservation for more
information and/or to donate to the noble cause of saving Britain’s swifts.
I hope that this unorthodox entry for the letter ‘A’ has boosted your appreciation of this amazing British bird and inspired you to gaze up at the skies this summer.
I hope that this unorthodox entry for the letter ‘A’ has boosted your appreciation of this amazing British bird and inspired you to gaze up at the skies this summer.
*In fact, hummingbirds evolved from a swift-like ancestor, becoming accomplished fliers in a very different way. The resemblance is clear if you compare them and think about the hummingbird with the beak trimmed. They were probably originally attracted to flowers by feeding on pollinating insects, which they still do alongside nectar-drinking.
ᵻ Those
tiny black ones that inextricably get caught in your hair, actually parachute
through the air on long lines of silk.
References
1Edward J. A. Drewitt and Nick Dixon (2008). Diet
and prey selection of urban-dwelling Peregrine Falcons in southwest England. British Birds Available from: http://media.wix.com/ugd//1ab07f_c7e226ec23e479a8218b52c35f7c39bb.pdf
