I love watching swifts fly, they are the most aerial of all birds and the word Apus is derived from the Greek Apous meaning footless. Swifts are pamprodactyly (pam – forward and dactyle – toes), this means all 4 toes face forwards so they can’t perch like normal birds but cling onto structures or land on their tummies on a beam or roof.
The Common Swift (hereby referred to as swift) spend 9 months of every year in flight, it even sleeps and mates in the air, being the only bird that mates this way.
A swift ringed in the UK was recaptured 18 years later and was estimated to have flown 4,8 million kilometers (3 million miles ) This equals going to the moon and back 8 times!
As dusk approaches swifts rise up in the air to about 10000 feet where they spend the night in a torpid state, descending at first light. Recent discoveries have shown that they also go up to 10000 feet in the morning.
Dr Johan Backman has demonstrated through experiments that the swifts shut down half their brains at night-time. He has found that swifts have an extraordinary ability to peform orientations in relation to wind whilst migrating and fast asleep and says that even the most advanced planes with excellent navigational instuments would be unable to judge the wind drift like swifts.
Swifts feed on tiny insects that float in the air (aerial plankton) including spiders. The chicks are fed a ball of insects containing anything from 300 to 1200 insects called a bolus, which weighs just over a gram. When it is raining heavily and the chicks can’t be fed they go into a torpid state, able to survive for 4-5 days until the weather changes. The only other bird to do this are hummingbirds (which are close relatives to swifts)
Other bird chicks would die within a few hours of not being fed. Incredibly swift chicks do press ups in the nest to build up their flight muscles, they have to be able to fly when they leave the nest, it’s fly or die for them.
A Peregrine Falcon in a dive is the fastest bird in the world but when it comes to level flight first place goes to the Spine Tailed Swift of Papua New Guinea at 169 km/h or 47 meters per second.
The common swifts arrive in SA sometime in October, I hope you agree with me that swifts are truly remarkable birds indeed.
Roy can be found in his shop at Casterbridge Lifestyle Centre, Roy Sarkin Jewellers, phone 013 751 2747. Birding is his hobby and he’s delighted to talk avian with any passersby!