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It's a daunting task of omission when one is asked to write a page long profile about an entire class of animals. Birds species number around ten thousand; they live on every continent; some fly in flocks that number over a billion; others fly in water like how as fish swim in a lake. One must stick to common characteristics of the class to keep the file size under a few kilobytes. The number one answer the public gives when asked about birds is that they can fly and they have feathers. However, only the latter is true for all birds. If the former was true, there might still be dodos left on this planet. Bird body feathers can number from 25,000 to a few thousand. The Tundra Swam, has the most, with around 25,000 but most of those are contour feathers that are found on the neck of it. You should wonder why? The long round & thin structure that is the shape of necks of some birds, legs of elephants and giraffes has the most surface area to volume ratio, thus creating a great place for heat loss. When you are amazed by the beauty and brilliance of a particular bird, you should also wonder about the relationships between form and function. In this short section on bird profiles, we will focus on the general profile of birds: topography, plumage, feet, beaks and wings.
Topography: Different bird orders will have a different body outline. One can easy tell the silhouette of a duck from a silhouette of a eage. These different body shapes correlates ecological function. Birds with large wing aspect ratios search far and wide for their foods, while birds with more rounded wings find their foods closeby, and need the more maneuverability that is given by shorter, rounder wings. Long legs in some wading birds give them the ability to track prey in deeper waters. Click on the pictures above to see some different shapes of birds.
Plumage: Birds have several different types of feathers on their bodies, such as contour feathers, Bristle feathers, Remiges, Rectrices, Adult down, Natal down, Powder feathers, Filoplumes and Semiplumes. Each type serves a different purpose. For example, powder feathers has barbs that will break down into power, this powder is helpful in waterproofing feathers. Bristles are found around the face, they are used for protection and also as a sensing organ. Birds such as night hawks have lots of bristles on their face. Remiges and Rectrices are flight feathers, but the later are the ones found on the tail. Adult down are the insulating feathers that lie under the contour feathers, while natal down is the down that hatchling precocial birds have.
Feet: Of all the body parts of birds, their feet are the most often overlooked. They are just as important as wings and beaks. Flightless birds such as the Kakapoo, Ostriches, and Kiwis spend all of their time on their feet, their feet takes them where wings do in the 10,000 other bird species. In Hawks, their feet are just as important as their wings & eyesight in aquiring prey. As far as pest control, feet are used to scratch discomfort caused by lice. There are five different types of toe arrangements in birds: anisodactyl, zygodactyl, heterodactyl, syndactyl and pamprodactyl. Feets that have other adaptions such as webbing are classified as: palmate, totipalmate, semipalmate and lobate. Birds of prey have raptorial feet; that are used to grasp and kill their prey. Raptorial feet may have two different toe arrangements, such as anisodactyl (hawks, eagles) and zygodactyl (osprey and owls). These unique shapes help biologist determine ecological function of bird in question. Beak: The structure of the bill itself is hollow bone, an outer layer of keratin covers it. Birds primarily use their beaks for feeding, but secondary functions include preening, defense and modifying their surroundings. Many of these other functions are just important in their lives as feeding. Some birds even use it as a way of communication, immature Brown Jays have different colored bills than the adults, signaling that they are immatures and won't threaten an alpha male's reproductive success, hence being allowed to stay on the land. Other such as toucans and hornbills will use their bills during pair bonding, breeding pairs will "bill" each other to strengten their pair bond. Titmice, Chickadees and Jays break seeds open by hammering them with their bill. Cardinals and Finches have stronger beaks, they are able to break the seed open by crushing it. Birds like pigeons simply swallow the seed whole, they allow their gizzards to break the seed for them. The Australian pelican has the longest bill at 18.5 inches, while the Glossy swiftlet has the shortest bill (just a few millimeters).
Wings: What is most unique about birds? They fly! Or at least most them do; its a characteristic that differs them from any other vertebrate taxon. Many human have been envious of that ability since prehistoric times, but it wasn't until recently that we mastered flight with airplanes. Some bird species such as the Common Swift will spend as long as three years on the wing, never landing, not even to sleep. Wings carry the Arctic Tern 24,000 miles from their migratory sites each year. Birds can fly through air and water with them, and in their temperately absence, it can allow them to free fall up to 200 miles per hour. Some birds such as vultures and albatross have huge wing aspect ratios that allows them to stay afloat in the smallest breezes without flapping. Other birds such as Copper's Hawks have more rounded wings that allow them to maneuver after prey in the thickest forests. Wings have many secondary functions such as defense (wing slap), cover their prey, swimming, help birds warm up, and hide their chicks under. We hope you received a good introduction in understanding birds or at least get a different perspective on them. The term "if you've seen one bird, you've seen them all," does not apply to this taxon or any other taxon. The information enclosed here is just a tiny tiny percentage of what ornithologists know about birds. Please continue to learn more about them. Blair Society recommendings either Ornithology by Frank B. Gill or Cornell Lab of Ornithology's Handbook of Bird Biology. If you can't afford the $113.95 copy of the 3rd addition of Ornithology, get yourself a used copy of the 2nd edition (still up to date) for less than a tenth of the price of the newer edition. |
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