Abstract
WEelcome to the AFA 2008 Conference! We gather in St. Louis to celebrate those marvelous, magical creatures we call birds.
Whether we keep birds as pets, breed them or admire them in the wild, they are our passion and, if we are honest, our great obsession. Now, all you cockatoo people, don't raise your crests; you Amazoniacs, no fanned tails please; you lory folk, no pinpoint pupils and you toucan people, stop playing with that ball. Everyone, just sit back, relax and let's talk about birds.
What is a bird? A simple answer is a warmblooded animal that has feathers and lays hardshelled eggs (at least we hope they are hard shelled, from the breeder's perspective). Going a bit deeper we find that most birds have modifications that enable them to fly. Their lungs are connected to air sacs that greatly enhance their capacity to extract oxygen from every breath. Their bones are honeycombed and much lighter than solid mammalian bones. They have no teeth but rather a very hard horny, but lightweight, bill (beak?). Most birds have a specially modified esophagus, or crop, to help store and digest food. To lighten the load on females, only one ovary is present and eggs are laid and incubated outside of the body, an adaptation that ties birds forever to the land to nest.
Birds occur on all continents. We find penguins on Antarctica, cockatoos in Australia, pheasants in Asia, capercaillie in Europe, turacos in Africa, the Hoatzin in South America and prairie chicken in North America. Even though it is not a continent, the Arctic has Snowy Owls. All together, there are between 8500 and 8700 species of birds, unevenly distributed over the globe. Tropical rain forests have a super abundance of species while temperate zones just get an elegant sufficiency of species. Few species occupy the open ocean where albatrosses glide over the waves and few species live in the desert like the roadrunner or the Budgerigar. There is even a hummingbird, the Chimborazo Star, that lives above the tree line on a volcano in Ecuador. All flying birds occupy the air for some period of time, none more than the swittlets who sail for months (nine or more between nesting) at a time in the air. Bar-headed Geese have been observed flying over Mount Everest, honking as they flew, while penguins have been recorded at 1700 feet beneath the ocean. Running birds such as ostriches, emus and rheas prefer open grassland or savannas.
Birds come in all sizes; at least they used to.
In the "good old days" when I was young (several hundred years ago), there were giant Moas in New Zealand, 10 foot tall weighing half a ton. The biggest bird alive today is the ostrich at about eight feet tall and 300 pounds, which makes a pretty good-sized drumstick to chew on. Of course, that is way too big to fly. At 35 pounds, swans are some of the heaviest birds to fly and need long runways for take off and landing. Andean Condors need broad, nine to ten foot wing spreads to maintain their soaring flight. At the other extreme, the Bee Hummingbird of Cuba is only two inches from beak to tail and one inch of that is beak and tail. Considering Psittacines, size varies from the giant Hyacinth Macaw at almost three feet long to tiny pygmy parrots less than three inches long.
Let us now consider several special features of birds: feathers, wings, beaks, feet, voice song or noise) box. Feathers are intricate structures that allow the infinite color variety of birds, and since bird's vision extends into the UV range, even more colorful than we can see. Feathers exhibit color through refraction and reflection of the underlying structure as in the iridescent throat patch of Rubythroated Hummingbird or the blue of Spix's Macaw. Feathers may also contain melanin substances that give them color. Turacos have a curious water-soluble chemical called Turacin for color and red parrots have their very own newly discovered, chemical, polyenal lipochrome, to make them red. Feathers cover most parts of birds other than their feet, with an occasional bald headed species like the picathartes of Africa or King Vultures of Central and South America. Some feathers provide insulation-think of the proverbial Eider down. Some feathers make the body sleek and aerodynamic, such as the outside body feathers of finches, for example. Specialized feathers, primaries and secondaries, in the wing allow controlled flight. There are other feathers which, when they break down, make the powder-down of cockatoo fame which covers all surfaces in a Cockatoaphile's home with a distinguished patina. There are even some feathers that are poisonous as in the Hooded Piyohui and the Bluecapped Ifrata of New Guinea.
What would the display of the lyrebird be without special tail plumes? The magnificent displays of the birds of paradise, the radiant tail of the peacock, the flash of the cockof-the-rock, the nuptial splendor of the Wood Duck and Mandarin, the waves of the ostrich plumes, all owe their effect to specialized feathers. Why, even the Audubon Society owes its existence to the show stopping plumes of the Snowy Egret. Other birds have lesser differences between male and female plumage and some are monomorphic. Many parrots, swans and geese for example are monomorphic, a fact that slowed successful reproduction in aviculture for centuries and has us singing the praises of DNA and surgical sexing available now.
There are distinct disadvantages to the birds thus advertising their presence; for example, becoming fast food for a passing predator. But, Dear Reader, consider we are talking here about males and what is a greater chance of dying to the male...