In the Beginning Was Information (34 page)
Read In the Beginning Was Information Online
Authors: Werner Gitt
Tags: #RELIGION / Religion & Science, #SCIENCE / Study & Teaching
A3.4.4 The Flight of Migrating Birds
The flight of birds is one of the most fascinating kinds of propulsion seen in creation. It involves numerous solutions which cannot be imitated technologically [D2, R3, and S2]. Aerodynamically, birds’ wings are highly specialized and optimized structures. Their curvature is especially important, otherwise they could not fly. An airplane has to have a fairly high minimum airspeed to stay airborne, but birds can utilize the updraught caused by their wing strokes to fly quite slowly. Their wings are carrier surfaces as well as propellers; the efficiency of the latter function is very high, and cannot yet be attained by technological means. We now discuss two of the numerous problems solved in the design of bird flight, namely the matters of
precise energy calculations
and
exact navigation
.
A3.4.4.1 The Flight of Migrating Birds: An Accurate Energy Calculation
Every physical, technological, and biological process strictly obeys the energy law, namely that a certain total amount of energy is required. Migrating birds have to carry enough energy in the form of fat to complete their journey, but birds’ bodies have to be as light as possible, so unnecessary weight should be strictly avoided. It is also necessary that fuel consumption should be optimal. How did the Creator provide for enough fuel without having "reserve tanks" or overnight "pit stops"? The first aspect is to determine the most optimal speed. If a bird flies too slowly, it consumes too much fuel for propulsion. If it flies too fast, then more energy is required to overcome air friction. There is thus a certain optimum speed for minimum fuel consumption. If the bird knew this special speed, it could fly the most economically. Depending on the aerodynamics of its body and its wings, every bird has a specific optimal speed (it is 45 km/h in the case of the Aztec seagull, for example; and 41.6 km/h for a parakeet). It is known that birds keep exactly to their optimum energy-saving speed when traveling. How do they know this? It is just one of many puzzles which ornithologists cannot solve.
We now consider the energy problem in more detail in the case of the golden plover
(Pluvialis dominica fulva)
. These birds migrate from Alaska to spend the northern winter in Hawaii. They have to fly non-stop over the ocean without resting, because there are no islands en route, neither do they swim. During this 88-hour journey of more than 2,485 miles (4,000 km) (depending on the point of departure), they beat their wings an enormous 250,000 times without stopping at all. At the start, their average weight G
0
is 200 g, 70 g of which is padding (fat) which serves as fuel. It has been found that these birds consume 0.6% of their weight per hour (fuel consumption p = 0.006/h) to produce propulsion energy and heat. During the first hour the amount of fuel x
1
it thus requires
(1)
x
1
=
G
0
x
p
= 200 x 0.006 = 1.2 g fat.
At the beginning of the second hour it weighs
G
0
-x
1
= 200 - 1.2 = 198.8 g, so that it consumes somewhat less energy during the second hour:
(2)
x
2
= (
G
0
-
x
1
) x
p
=
G
1
x
p
= 198.8 x 0.006 = 1.193 g
(3)
x
3
= (
G
0
-
x
1
-
x
2
) x
p
=
G
2
x
p
= 197.6 x 0.006 = 1.186 g
For the 88th hour the fuel consumption is down to
(4)
x
88
= (
G
0
-
x
1
-
x
2
-
x
3
-… -
x
87
) x
p
=
G
87
x
p
because of its reduced weight. We can now calculate its weight at the end of the journey, after subtracting the hourly weight reduction:
(5) 1st hour:
G
1
=
G
0
-
x
1
=
G
0
-
G
0
x
p
=
G
0
(1-
p
)
(6) 2nd hour:
G
2
=
G
1
-
x
2
=
G
1
-
G
1
x
p
=
G
1
(1-
p
) =
G
0
(1-
p
)
2
(7) 3rd hour:
G
3
=
G
2
-
x
3
=
G
2
-
G
2
x
p
=
G
2
(1-
p
) =
G
0
(1-
p
)
3
. . .
(8) zth hour:
G
z
=
G
z-1
-
x
z
=
G
z-1
-
G
z-1
x
p
=
G
z-1
(1-
p
) =
G
0
(1-
p
)
z
. . .
(9) 88th hour:
G
88
=
G
87
-
x
88
=
G
87
-
G
87
x
p
=
G
87
(1-
p
) =
G
0
(1-
p
)
88
The hourly weights
G
0
,
G
1
, …,
G
88
form a geometric sequence with common ratio q = 1 -p < 1. This computation is somewhat oversimplified,
[29]
but, by substitution in (9) we find the final weight after 88 hours to be:
(10)
G
88
= 200 x (1 - 0.006)
88
= 117.8 g
The total fuel consumption is given by
(11)
G
0
-
G
88
= 200 - 117.8 = 82.2 g
which is appreciably greater than the 70 g of fat the bird started out with! The bird’s weight cannot go below 130 g (see Figure 45). In spite of flying at the optimum speed for minimal fuel consumption, the bird would not be able to reach Hawaii because it started out with too little fat. To determine the number of hours that the bird could fly with the given amount of fuel, we have to solve the following equation for z:
G
z
=
G
0
x (1-
p
)
z
= 200 - 70 = 130 g.
 |
Figure 45: |
The result is that the 70 g of fat will be consumed after 72 hours, which is 81% of the required flying time. This means that the bird would plunge into the ocean about 497 miles (800 km) short of its destination. Did we make some mistake, or has the bird been inadequately constructed by the Creator? The answer to both questions is "no." We regard the Creator’s work with amazement. He employs the fundamental theorem which states that "energy input is optimized through information." In the case of the plover, this means that the bird has been given some important additional information, namely: "Do not fly
alone
(curve
G
A
), but fly in a
V formation
(curve
G
V
)! In the V formation, you will save 23% of your energy and will then safely reach your destination." Curve
G
V
in Figure 45 depicts the weight decrease in V formation. After 88 hours, the normal residual amount of fat is 6.8 g, which has not been carried along unnecessarily, but is a reserve to be used when head winds are encountered. The extremely low specific rate of fuel consumption,
p
= 0.6% of its weight per hour, is all the more amazing when we compare it with that of man-made aircraft which is many orders of magnitude greater (for a helicopter
p
= 4 to 5%; and
p
= 12% for a jet plane).
Somebody who does not regard these precise phenomena as the work of the Creator cannot answer the following questions:
– How does the bird know the exact energy requirement?
– How is it possible that the bird accumulates the exact amount of fat before the journey?
– How does the bird know the distance and the specific fuel consumption?
– How does the bird know the migration route?
– How does the bird navigate to reach its destination promptly?
– How does the bird know to fly in a V formation with other birds to reduce fuel consumption?
In my book
If Animals Could Talk
[G15], the golden plover acts as narrator involving the reader in an imaginary dialogue. The facts presented here are used as point of departure to draw the reader’s attention to numerous wonders of creation.
Besides the Eastern Siberian golden plover mentioned above, there is also the North American golden plover
(Nominatrasse)
. These birds also undertake a non-stop long distance migration flight from the coast of Labrador across the Atlantic Ocean to Brazil. The western plovers follow the same route for both the outward and the return journey, but the American plovers use different routes in autumn and spring. On the northward leg, they fly back to Canada over Central America and the United States. Some further astonishing migration feats are:
– The Japanese snipe
(Capella hardtwickii)
flies 5,000 km to Tasmania.
– The East Siberian spine-tailed swift
(Chaetura caudacuta)
from Siberia to Tasmania.
– The migration route of the American sandpipers (e.g.,
Calidris
melanotus
= grey breasted sandpiper) covers 16,000 km from Alaska to Tierra del Fuego at the southern tip of South America.
A3.4.4.2 The Flight of Migrating Birds: A Navigational Masterpiece
Finn Salomonsen, a Danish ornithologist, writes the following about the in-flight orientation of birds [S2]: "The ability of birds to find their way while flying is a mystery and a puzzle. Few other questions have over the years given rise to so many theories and speculations as this one." This navigational ability is indeed a supreme wonder, since birds do not have complex gyroscopes, compasses, or maps, and environmental conditions like the position of the sun, wind direction, cloud cover, and day-night rhythms, keep changing all the time. When terrestrial birds have to cross an ocean, as we have seen in the case of the golden plover, a small error in direction would result in their floundering helplessly over the open ocean and finally plunging to their death. Setting an exact course is not a question of trial and error, because a large majority of the migratory birds would never reach their destination without exact navigation. No species could survive such great losses. Any evolutionistic view of this fact can be rejected out of hand. The idea that juvenile birds are shown the way by their parents plays a minor role at most, since many kinds of birds fly singly. We thus have to assume that migratory birds possess an inherent sense of direction which enables them to orient themselves with respect to geographical direction and to stay on course. This sense of direction is demonstrated by Salomonsen in the case of two kinds of small birds living in western Greenland and which both migrate to the south in autumn. The wheatear
(Oenanthe oenanthe)
and the snow canary live in the same region, and they often begin their migration at the same time, but their ways part after arriving in southern Greenland. The snow canaries continue directly south to spend the winter in America, while the others turn southeast and fly right across the Atlantic Ocean to western Europe and North Africa. Both kinds of bird have a specific sense of direction which determines their different courses.