Kingfisher: Blue Or Green?

Quite a few people in this country will tell you they have never seen a kingfisher

Quite a few people in this country will tell you they have never seen a kingfisher. They are not that scarce; estimated breeding pairs are from 1,300 to 2,100, and these are, according to Cabot, scattered thinly throughout the island. The same authority says they are to be found on freshwater canals, sluggish rivers, streams and lakes. Anglers of the more relaxed sort, who find as much pleasure in observing all around them as they do in landing a trout - at least they excuse themselves with the explanation - will confirm that on the smaller rivers of the middle of Ireland, there is hardly a stretch where you won't sooner or later see that exciting flash of brilliance.

There is some difference of opinion on the exact colours of this small jewel. Upper parts are a greenish-blue, underparts a chestnut. The throat is white and there is a white patch on the neck or cheek. It is a bit bigger then the robin. A book published in 1997 explains a colour dilemma that one family argued long about. Appalled looking out the main window they saw twitching on the grass, two small objects, green and flashing. On inspection they found two kingfishers. One died quickly, one, taken to the vet, died the next day.

They had, possibly fleeing from some predator, come around the bend of the river and mistaken the glass sliding doors as an extension of the water. But kingfishers are blue on top, aren't they? Now Charlie Hamilton James in his book King- fishers (published by Colin Baxter) explains. "Their bright feather colours are not due to true pigment, for true blue pigment does not actually exist in birds. Rather, the astonishing colours of the upper parts of the kingfisher are the result of a complex structure in the layers of the feathers, which filters out certain colours of light, reflecting back only blue. This is known as the `Tyndal effect' and as a result of it the kingfisher can appear to turn from bright blue to the rich emerald green with only a slight change in the angle at which the light falls on it."

If you live on or near a river and kingfishers patrol it, you might be able to hammer a post in midstream. They will appreciate it, and often land on it, either for rest or to dive for fish from it. An oak tree, which grew laterally instead of vertically on a river bank, made a fine platform from which to dive for minnows. The book, so brilliantly illustrated, cost £5.40 from Fred Hanna in Nassau Street, Dublin.