P
peter hayes
Guest
This is worth a glance I reckon..................
In 1938 an American newspaper published a report from a pilot who was
nose-diving at 170mph. The speed of his plane wasn't exceptional. What
was remarkable was that he was passed by a diving peregrine stooping on
some ducks "as though the plane was standing still". In 1955 another
observer used a stop-watch to record the speed of needletail swifts
crossing a valley in the Cahar Hills of Assam. The valley was two miles
broad and the birds took between 32.8 and 41.8 seconds to traverse it.
Thus the fastest speed was 219.5mph.
Why are these claims difficult to accept? Chiefly because the speeds
are so much in excess of the known speeds of such fast fliers as the
racing pigeon. A careful experiment was conducted with Royal Air Force
pigeons during the Second World War. The speed calculated was the
average of a two-way flight. The fastest individual travelled at
58.7mph. Interestingly, this almost matches the quickest recorded speed
for a European swift - a 'mere' 60mph. Furthermore, although they cannot
fly, ostriches can trot at speeds of up to 45mph.
Naturally the pace of a bird running on land is much easier to measure
accurately as its speed is due entirely to its own efforts, without help
from gravity or wind. This is why contradictory figures are arrived at
for birds in flight. A species diving in a strong tail-wind may well
reach 100mph; climbing against the wind the same bird may clock only
10mph.
Nearly all birds have two, and some three speeds: for cruising,
emergencies, and migration. A bird that normally flies at 20mph may
average 30mph on migration, and in panic flight before a predator may
reach 40mph for a few seconds. Impressions can also be misleading. The
smaller the bird the faster it seems to be travelling. Actually, larger
birds like geese are among the swiftest, sometimes attaining an
air-speed of a mile a minute. This is about twice the speed of small
birds which appear to dart about so quickly.
The most impressive statistics are those charting the distances covered
by birds in short periods of time. Lapwings are known to have crossed
the Atlantic from Britain to Newfoundland in about 24 hours. They had to
travel 2,200 miles and the average speed was, therefore, close to 90mph.
But this does not mean that the lapwings flew at this speed. At the time
a 55mph tail-wind was blowing across the Atlantic from Europe to Canada,
accounting for over half the birds' speed. A paper bag, blown along by
such a wind, would have travelled at over 60mph.
Seabirds probably hold the record for the fastest wind-assisted speeds.
Albatrosses and shearwaters are long-winged and built like gliders.
Several species spend their entire lives in the strong winds of the
'roaring forties' in the Southern Hemisphere. Ranging up to 350 miles in
the course of a day's flying is part and parcel of their foraging routes
over the ocean, but almost all of the effort is provided by wind.
Indeed, the longest-winged species scarcely need to flap at all.
Momentum is maintained by the strength of the wind over the sea and air
turbulence created by waves gives the birds the lift they require. In
complete contrast, hummingbirds are only able to hover by beating their
winds constantly. They have the fastest wing-beat of all. The wings
complete 75 up and down movements in a second. The house sparrow beats
its wings almost 13 times a second in fast flight - the heron just two
or three. Taking off requires most energy. If a bird is made to rise and
fall several times in quick succession it will eventually stay panting
on the ground.
In athletics and motorsport we tend to regard short sprints and fast
acceleration as the measure of swiftness. How quickly can someone run
100 meters or how many seconds does it take for a formula one racing car
to reach 60mph? Some of the quickest birds are shorebirds and wildfowl.
Teal are the smallest duck and, unlike most wildfowl, do not need to
taxi to take off. They spring into flight and twist and turn at speeds
of up to 60mph. Golden plover are capable of outflying a pursuing
peregrine in level flight. However, if the falcon can gain height and
keep its quarry below it, then the added speed derived from gravity in a
stoop will enable it to overhaul its prey. Should a peregrine attack
from high above and drop like a stone on its victim, them its velocity
rockets to a staggering 180mph.
Is there an official record-holder, a Linford Christie of birds? Like a
true sports competitor, wind assistance should not be permitted to boost
performance and the contender must be measured in level flight in still
air. In practice this test has not been applied to birds - but it has in
theory. The results are surprising. Engineers assessed body size,
wingloading and general aerodynamic design and tested several bird
models under laboratory conditions. Wildfowl again emerged as potential
speed merchants. And the title of hot rod of the air? Because of its
concorde-like front end and powerful, ergonomically-shaped wings and
body, researchers concluded that, if it wanted to, the humble eider
could be the fastest flying bird on the planet. Eiders, on the other
hand, are more interested in using those turbo-changed wings to help
them pursue food under water.
In 1938 an American newspaper published a report from a pilot who was
nose-diving at 170mph. The speed of his plane wasn't exceptional. What
was remarkable was that he was passed by a diving peregrine stooping on
some ducks "as though the plane was standing still". In 1955 another
observer used a stop-watch to record the speed of needletail swifts
crossing a valley in the Cahar Hills of Assam. The valley was two miles
broad and the birds took between 32.8 and 41.8 seconds to traverse it.
Thus the fastest speed was 219.5mph.
Why are these claims difficult to accept? Chiefly because the speeds
are so much in excess of the known speeds of such fast fliers as the
racing pigeon. A careful experiment was conducted with Royal Air Force
pigeons during the Second World War. The speed calculated was the
average of a two-way flight. The fastest individual travelled at
58.7mph. Interestingly, this almost matches the quickest recorded speed
for a European swift - a 'mere' 60mph. Furthermore, although they cannot
fly, ostriches can trot at speeds of up to 45mph.
Naturally the pace of a bird running on land is much easier to measure
accurately as its speed is due entirely to its own efforts, without help
from gravity or wind. This is why contradictory figures are arrived at
for birds in flight. A species diving in a strong tail-wind may well
reach 100mph; climbing against the wind the same bird may clock only
10mph.
Nearly all birds have two, and some three speeds: for cruising,
emergencies, and migration. A bird that normally flies at 20mph may
average 30mph on migration, and in panic flight before a predator may
reach 40mph for a few seconds. Impressions can also be misleading. The
smaller the bird the faster it seems to be travelling. Actually, larger
birds like geese are among the swiftest, sometimes attaining an
air-speed of a mile a minute. This is about twice the speed of small
birds which appear to dart about so quickly.
The most impressive statistics are those charting the distances covered
by birds in short periods of time. Lapwings are known to have crossed
the Atlantic from Britain to Newfoundland in about 24 hours. They had to
travel 2,200 miles and the average speed was, therefore, close to 90mph.
But this does not mean that the lapwings flew at this speed. At the time
a 55mph tail-wind was blowing across the Atlantic from Europe to Canada,
accounting for over half the birds' speed. A paper bag, blown along by
such a wind, would have travelled at over 60mph.
Seabirds probably hold the record for the fastest wind-assisted speeds.
Albatrosses and shearwaters are long-winged and built like gliders.
Several species spend their entire lives in the strong winds of the
'roaring forties' in the Southern Hemisphere. Ranging up to 350 miles in
the course of a day's flying is part and parcel of their foraging routes
over the ocean, but almost all of the effort is provided by wind.
Indeed, the longest-winged species scarcely need to flap at all.
Momentum is maintained by the strength of the wind over the sea and air
turbulence created by waves gives the birds the lift they require. In
complete contrast, hummingbirds are only able to hover by beating their
winds constantly. They have the fastest wing-beat of all. The wings
complete 75 up and down movements in a second. The house sparrow beats
its wings almost 13 times a second in fast flight - the heron just two
or three. Taking off requires most energy. If a bird is made to rise and
fall several times in quick succession it will eventually stay panting
on the ground.
In athletics and motorsport we tend to regard short sprints and fast
acceleration as the measure of swiftness. How quickly can someone run
100 meters or how many seconds does it take for a formula one racing car
to reach 60mph? Some of the quickest birds are shorebirds and wildfowl.
Teal are the smallest duck and, unlike most wildfowl, do not need to
taxi to take off. They spring into flight and twist and turn at speeds
of up to 60mph. Golden plover are capable of outflying a pursuing
peregrine in level flight. However, if the falcon can gain height and
keep its quarry below it, then the added speed derived from gravity in a
stoop will enable it to overhaul its prey. Should a peregrine attack
from high above and drop like a stone on its victim, them its velocity
rockets to a staggering 180mph.
Is there an official record-holder, a Linford Christie of birds? Like a
true sports competitor, wind assistance should not be permitted to boost
performance and the contender must be measured in level flight in still
air. In practice this test has not been applied to birds - but it has in
theory. The results are surprising. Engineers assessed body size,
wingloading and general aerodynamic design and tested several bird
models under laboratory conditions. Wildfowl again emerged as potential
speed merchants. And the title of hot rod of the air? Because of its
concorde-like front end and powerful, ergonomically-shaped wings and
body, researchers concluded that, if it wanted to, the humble eider
could be the fastest flying bird on the planet. Eiders, on the other
hand, are more interested in using those turbo-changed wings to help
them pursue food under water.
