Hummingbirds: the Fairies we see
Many of us have seen hummingbirds, those iridescent little flitters in our gardens, or they come to our feeders. Why do they seem to have iridescent colorations? Why they are only found in the Americas? Where do they come from? And how can they seem to float like that? Hopefully I will be treating you to a little new knowledge in these areas.
Hummingbirds are known by some as garden fairies, flitting from plant to plant they can be beautifully iridescent. When during the mating season this becomes more evident. Believe it or not, the pigments in hummingbird feathers are just one dull color! So why do they show such vivid blues, reds greens and yellows? The pigments are dispersed to reflect certain light at the correct angle, sort of like the color changing ink we use on money (this is the way we got that idea). For more on this read this or this.
The pigments (melanin) in hummingbird barbules are dispersed in a special way. What are barbules you ask? It seems their feathers are made up of tiny feathers known as barbs, and those of even tinier ones that are barbicels. When viewed from one angle they show that trademark iridescence, but when viewed from another they seem much duller or even of an entirely different color. They can even control how these feathers are moved, like an animal twitching its skin. This is due to the interference of light and the reflective qualities of these pigments which are ‘stacked’ atop each other.
Swifts and Hummingbirds are distantly related, both are members of the order APODIFORMES. Both eat insects, but hummingbirds are specialized ‘nectivores’ that means they eat nectar. However, where Swifts are found all over the world, hummingbirds (Family Trochilida) are only found in the Americas, and though many can be found in both North and South America, most North American hummingbirds winter over in Central or South America.
It seems that hummingbirds co-evolved with ornithophilous flowers. This means that they (the flowers) are pollinated by birds. Flowers of this type do not reflect light at the higher end of the spectrum, up near the ultraviolet, making them invisible to insects. While birds do see into the ultraviolet, we can speculate here that they may ‘see’ the flowers by their absence.
Well, as we saw in the PBS Video: Magic in the Air , hummingbirds can flap their wings in a figure eight pattern. Amazing isn’t it? That’s the secret of their hovering ability. But not only can they flap in a figure eight, but up to 1/3 of their body mass is flight muscle! They flap up to 80 beats per second. That’s not nearly as fast as their hearts can sometimes beat, yes their hearts can beat over 1200 times per minute during flight.
Well, the ‘jewels of the sky’, as they are known by some, are pretty little flyers. Their feathers are amazingly specialized. They’ve evolved side by side with certain flowers, and though those kinds of flowers may be found elsewhere, hummingbirds are only from the Americas. They winter in much warmer climates, but wouldn’t we all if we were so tiny! So feed those ‘garden faeries’ from March to August, in the north, or all year in some southern areas of North America. Oh! And don’t forget to try to abstain from the use on insecticides, with the proteins and vitamins and minerals of their diet coming from insects you wouldn’t want to accidently poison these tiny birds.