At the beginning of the week, I was walking through a water
meadow when a kingfisher flew by, perched on a tree branch, and then darted off
and away under a bridge and out of view. I always love seeing kingfishers, even
when I'm not lucky enough to be able to admire them through binoculars, and
there's something thrilling about their wonderful colours and their habits.
It is a feeling that I, and many others, share with Charles
Waterton, who wrote in his Essays on
Natural History [1]:
When the delicious season of
spring sets in, I often get up into the topmost branches of a wide-spreading oak
[Waterton was an enthusiastic climber of trees]; and there, taking the Metamorphoses out of my pocket, I read
the sorrows of poor Halcyone. A brook runs close by the tree, and on its bank I
have fixed a stump for a resting-place to the kingfisher. On it, this pretty
bird will tarry for a while in passing up and down, and then plunge into the
stream, and bring out a fish. My elevated station on the oak gives me a fine
opportunity of admiring its back, as it darts along beneath me. When the
sunbeam is upon it, no words can do justice to the beauty of the glowing azure
which attracts the eye.
In the passage of Metamorphoses
[2] that Waterton was reading, Ovid describes how Alcyone and her husband Ceyx
die and:
..both were changed to birds, the
halcyons. Though they suffered the same fate, their love remained as well: and
their bonds were not weakened, by their feathered form. They mate and rear their
young and Alcyone broods on her nest, for seven calm days in the wintertime,
floating on the water's surface.
Although, Morford and Lenardon [3] describe them as
seabirds, Alcyone and Ceyx are more commonly regarded as kingfishers, just as
Waterton supposed. Given their splendid appearance, it is not surprising that kingfishers
play a role in mythology, although one of the myths that surrounds the birds is
much more prosaic. In Britain, a kingfisher suspended on a string is thought to
act as an effective weather vane, a practice that continued up to the 1920s in some
areas [4].
The blue colour of the feathers is not caused by pigment but
by iridescence, as described by Silvia Vignolini [5]:
Most vertebrates are unable to
produce blue pigment. The orange of kingfisher plumage is the product of tiny
pigment granules but its cyan and blue feathers contain no pigments. These
colours are 'structural'. They are created by the intricate structural
arrangement of a transparent material which, depending on its precise make-up
and thickness compared to the tiny wavelength of light, produces a range of
colours by 'incident light' – in other words light shining on the sample..
..Kingfisher feathers reflect light in a way that scientists describe as
semi-iridescent.. ..Iridescence is produced by the ways in which layers of
material are perfectly aligned and repeated periodically to achieve a shimmer
effect. Semi-iridescence is produced when the layers are not quite perfectly
aligned but slightly disrupted, thus causing a smaller span of iridescent
colour.
A little complicated, but it is clear that the blue feathers
of the kingfisher are the result of optical effects and not pigment, while the
orange feathers do contain pigment. The overall effect is appreciated by all of
us who see the birds flashing by when we take a walk, or sit in a tree, and it
is easy to see how they have stimulated poets like William Henry Davies [6] and
Gerard Manley Hopkins [7], as well as being the source of myths. Kingfishers of
various kinds also feature in Japanese prints, while the blue, semi-iridescent
feathers of the Eurasian kingfisher have been used by Chinese artists in the manufacture
of tian-tsui [8 - and see above]. It is not just the colour and habits of the kingfisher
that have stimulated our imagination, as the shape of the beak of an Eastern
species was the inspiration for the design of the nose of the 500 series Shinkansen
trains in Japan [9 – and see below]. Both structures have an optimal design to
reduce pressure: for the kingfisher when diving into water, and for the Shinkansen
500 when passing through tunnels and other constrictions that reduce the easy
displacement of air.
It is tempting to think that the structure and appearance of kingfishers were somehow designed for our benefit and some Creationists
may believe this to be so. In contrast, they are more likely to result from evolutionary processes
that selected for mutations affecting changes in the shape of the beak and
colours of feathers that, far from camouflaging the bird, make them highly
visible. We don't know why that should be and neither can we know how
kingfishers look to other kingfishers. However, I'm so pleased that they
evolved in the way that they did.
[1] Charles Waterton (1839) Essays on Natural History, chiefly Ornithology. London, Longman,
Orme, Brown, Green and Longmans.
[2] Ovid Metamorphoses
(A. S. Kline version of the Latin text) http://ovid.lib.virginia.edu/trans/Metamorph11.htm
http://ovid.lib.virginia.edu/metamorphoseonUVA.html
[3] Mark P. O. Morford and Robert J. Lenardon (2007) Classical Mythology. Oxford, Oxford
University Press.
[4] Steve Roud (2003) The
Penguin Guide to the Superstitions of Britain and Ireland. London, Penguin
Books.
[5] Silvia Vignolini http://www.cam.ac.uk/research/features/k-is-for-kingfisher
[8] https://www.vastari.com/chinese_blues_the_ancient_art_of_tian_tsui_Featured.aspx?id=MjubV1inUZc=
[In this post, the kingfisher referred to is Alcedo atthis, unless otherwise stated.]
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