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Swifts

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Any ornithologists out there?... i read recently that "swifts sleep on the wing" How do 'they' know that?.... can you think of a way of finding it out?
 
Maybe it's a sort of 'auto pilot' function rather than actual sleep, Jon.

Carole
 
and how would anyone know that?... what is sleep scientificly what qualifies as sleep?....
 
It's another level of consciousness, I suppose.

Carole
 
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Do they indeed!....... i dont know and the dificulty of establishing it in flight is another question!... Is it perhapse something to do with REM (rapid eye movement) sleep i.e. dreaming?
 
I remember a thing about sharks never sleeping because they would die if stopped swimming and swooshing water through their gills. That was followed up with an idea that they 'semi sleep' while swimming slowly. Maybe Swifts do the same sort of micro power nap. But surley they can't spend their entire lives on the wing... they nest don't they? I'd catch a brief nap then.
 
And they have to mate too (or do they do it like that old T-Shirt slogan - 'Fly United'?)

Carole
 
sam said:
I remember a thing about sharks never sleeping because they would die if stopped swimming and swooshing water through their gills. That was followed up with an idea that they 'semi sleep' while swimming slowly. Maybe Swifts do the same sort of micro power nap. But surley they can't spend their entire lives on the wing... they nest don't they? I'd catch a brief nap then.


yes but i saw a Cousteau prog that had sleeping stationary sharks in it! Sharks can pump water past thier gills when not on the move it seems as can most fish. ... im still wondering how Swifts are judged to sleep "on the wing" it seems a blithly simple statement with no backing!........ Swifts do land but they cannot take off from the ground (i know i resucued one once from the road) perhapse they do sleep hanging on to things...
 
Swifts do most things flying - including mate . They only land to nest and rear their young , the young , when they fly , do not land again until they make their own nests as adults so presumably they either sleep ( probably in very brief moments ) on the wing or don't sleep at all . They do not have normal feet , just small gripping toes - these are very strong ! If you rescue a downed swift it will not be releasable unless you can feel it 'buzzing' , it might need keeping in a small safe box overnight if it has been stunned on a window . Downed swifts give off the most unbirdlike ( more mammalian ) screams and swim around on the ground with their wings but seem not to suffer the stress some other weaker birds have when they are injured.
 
i found it on the pavement poor thing just sitting there... i took it out to the rear carpark where it had a good flight path.. it crawled up my jumper to my shoulder and in amost breathtakeing swoop zoomed over the roof tops after nearly touching the ground.... i thought "my life hasnt been waisted then"
 
From Richard Fitter (ed.), (1969), The Book of British Birds, Drive Publications, London, p46:

[Swifts'] legs have become so weak, because they are so seldom used, that the birds are helpless and easily caught once on the ground; but swifts never alight on the ground except by accident. They feed on the wing, sometimes mate on the wing [!], and even sleep on the wing. At dusk, swifts circle higher and higher until they disappear from sight. It used to be thought that they returned after dark to roost at their nests, but it is now known that those which are not incubating eggs or brooding young remain aloft until sunrise, probably cat-napping on currents of rising air between short spells of flapping to gain height.

From Oliver L Austin, (1968), Birds of the World, Spring Books, London, pp165-166:

Their flight is so effortless that swifts apparently need little rest. They probably spend more of their waking hours in the air than do any other land birds. An ancient belief had it swifts roosted in the Heavens. In recent years two lines of research have been used to show that some swifts do spend the night on the wing. One was to fix an automatic device to the entrance to the nests to register whether the birds entered or left them during the hours of darkness. The other was to go up in aeroplane and actually see the birds at night.

From ibid., p165:

The swifts' short legs and small, weak feet will not support them in normal fashion. They never perch on tree branches, and few can raise themselves high enough off flat ground to give their wings play to take flight. They roost clinging up-right to vertical suefaces with their sharp toenails, propped against cliff walls, tree trunks, or chimneys by their short tails.

Gilbert White also noted the swift's aerial copulation, in The Natutal History of Selbourne (1996 reprint, p207):

The fact I would advance is, that swifts tread, or copulate, on the wing; and I would wish any nice observer, that is startled at the supposition, to use his own eyes, and I think he will soon be convinced. In another class on animals, viz. the insect, nothing is so common as to see the different species of many genera in conjunction as they fly. The swift is almost continually on the wing; and as it never settles on the ground, on trees, on roofs, would seldom find opportunity for amorous rites, was it not enabled to indulge them in the air. If any person would watch these birds on a fine morning in May, as thye are sailing round at a great height from the ground, he would see, every now and then, one drop on the back of another, and both of the sink down together for many fathoms with a loud piercing shriek. This I take to be the juncture when the business of generation is carrying on.

The swift is not the most amazing, though! From Mark Carwardine, (1995), The Guinness Book of Animal Records, Guinness, Middlesex, pp127-128:

The most aerial of all birds is the sooty tern, which is widespread throughout the tropical oceans. After leaving its nesting grounds as a youngster, it is reputed to remain aloftr continuously for 3-10 years until it is old enough to breed for the first time. Although this is impossible to prove, research suggests that it does not need to return to land to rest but, as long as there is enough food available, can stay in the air indefinitely. It does not even need to settle on the sea to feed, preferring to catch fish or squid by picking them from the surface while hovering or by seizing them in mid-air when they jump to escape underwater predators.

The most aerial land bird is the common swift, which remains airbourne for 2-4 years after fledgling, during which time it sleeps, drinks, eats and even mates on the wing. Its flight is about 70 per cent more efficient than that of other birds of cpmparable size, because it has long wings and a low body mass in relation to wing area (to reduce energy expenditure) and a shallow, forked tail that reduces drag and increases lift. Like a sooty tern, it has to come to land only when it is ready to breed.
 
I don't agree that their feet are weak - as described in evilsprout's references . Their feet have an incredible springlike gripping strength . Just because they can't walk with them it doesn't make them weak !
 
the one i saw up close looked most delicate and scaley ... like a lizards foot.. but with almost no leg bit, just all spidery claw...
 
I've always found swifts to be rather frightening looking. Is it just me? They look like small demons, and I've always wondered if they were the subject of much superstition. They're so incredibly well designed for flight that they seem almost like perfect machines. :monster:
 
part of the reason i like them so much is they are dead ugly close up, but in the air, nothing can touch thier beauty..........
 
Funny, I was going to start a thread asking whether all animals (inc. birds, fish) sleep... but this seems to be going in the same direction anyway. Great minds think alike, or the Idea virus is particually virulent this week :)

As to whether anyone actually knows whether swifts sleep on the wing... much as I would like to imagine David whatshisname hovering in a helicopter studying the eye movements of these little demons, I suspect it's just conjecture.

Talking of birds, who knows anything about puffins (I know one of you must!). They're not the most gainly birds in the air, but nobody seems to know where they go in the winter - do they bob gently on the huge Atlantic swells, or what?

Jane.
 
i like puffins!... and i must admit i didnt know they went anywaher in winter..perhapse they go to sunny spain!... i saw a Tv prog about them and seeing them underwater flying was amazeing.. 20 meters down!...and they can fly in air too!... uterlay amazeing birds... major question about puffins is how do they catch a beek ful of sand eels without the previose eel excapeing!
 
Puffins!

Just for you, Jon...

http://birding.about.com/library/weekly/aa082397.htm

You live in Cornwall? Plenty of opportunity to see these lovely birds on the sea cliffs and islands then :)

Here in sunny (ha!) Oxfordshire, we have swifts clingling to the walls (next to the young bats on my house :) )

The only time I've seen puffins up close was on the island of Staffa (sp??) off the coast of Scotland - one stole my sardine sarnie!!

Jane.
 
thanks we got nesting Choughs now too!..they spent all sorts of money (government and EEC) on breeding some and setting em free....then a pair turn up out of nowhere and nest... i rekon they were there all the time just waiting....
 
Here in Sussex, on the County coat of arms appears the mythical Martlett, which is supposed to be similar to the Swift or Martin. The bird doesn't have feet, just a huge tuff of feathers on its belly. It doesn't need feet or even legs as never lands and is forever moving.
 
I wonder if the swift gave the designer of the spitfire his inspiration as their sillhouettes seem very similar to me.

Dolphins sleep half a brain at a time,
or did I just make that up?
 
The Lecky Mouse said:
Dolphins sleep half a brain at a time,
or did I just make that up?

I can't say I've heard it before lecky, but if it's not true then it certainly should be. I remember mentioning somewhere that humans can only breathe through one nostril at a time, but nobody believed me so I must be a genetic mutant :D

Jane.
 
I seem to remember that swifts fly very high then "catnap" on the way down ,gliding. Another old name for them is Devilbird, because off their looks and the noise they make.
 
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beakboo said:
I've always found swifts to be rather frightening looking. Is it just me? They look like small demons, and I've always wondered if they were the subject of much superstition. They're so incredibly well designed for flight that they seem almost like perfect machines. :monster:

One of our cats once caught one (or maybe a house martin, same family anyway) by some complete fluke and they have an almost oriental look about them round the eyes.

I was watching them round our house on Sunday night, it was a lovely calm night and they were 'joy riding' round the roof tops, then swooping low and giving what sounded like little squeals of sheer joy. They're wonderful to watch.

Carole
 
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