What is a bird and what good is it?

Written by Jack Sanders
Thursday, 20 October 2011 11:07

Just what is a bird and what do birds contribute to the world?

Although an ornithologist could offer a tongue-tying official definition of a bird, here’s a simple one: A bird is an animal with feathers. No other kind of creature on earth has feathers, and no bird on earth lacks them. Thus, if you see something moving with feathers on it, you can be pretty certain it’s a bird.

A scientist can add a few more characteristics. For instance, a bird is a vertebrate chordate, which means it has a backbone made up of lots of small bones. Mammals share that feature. Birds are also warm-blooded, another characteristic found in mammals.

Birds are toothless and instead of teeth have a horny bill. Thus, Earth’s fastest creatures share a characteristic with one of Earth’s slowest, the turtle.

All birds lay eggs, but so do insects, spiders, fish, reptiles, and amphibians.

The forelimbs of birds have been modified to form wings. While flight is probably the characteristic we think of first when we consider the features of a bird, it is not a defining characteristic because the wings don’t always work. Such birds as penguins, emus, and ostriches can’t fly. What’s more, plenty of insects do. In fact, there is even an insect that often gets confused with a bird: The Hummingbird Moth. And, of course, bats, which are mammals, fly, too.

All birds have two legs, a feature shared with primates like man.

What good are they?

If all the world’s birds were to suddenly disappear, Earth would be in a lot of trouble. First off, the world would be overrun with insects, which birds are instrumental in keeping under control. The populations of many kinds of small mammals, such as mice, voles, and rabbits, would explode. These uncontrolled populations of insects and mammals would not only be unpleasant, but would do immense damage to vegetation — from trees and shrubs to crops — and many people would starve.

Birds are also planters. Seeds in the berries that birds eat pass through their digestive system and are deposited far and wide. Some birds literally plant seeds, such as acorns, by caching them in the ground for future use.

Birds are pollinators. They pollinate more than 150 species of plants in North America.

Birds are also a source of food — from domestic chickens, turkeys and ducks to wild game. Their eggs are among the most popular foods. The American Egg Board reported a few years ago that about 240 million laying hens produce approximately 5.5-billion dozen eggs per year in the United States.

Birds are a source of warmth. Down feathers are still widely used for insulating material.

Birds are also companions. According to the American Pet Products Manufacturers Association in 2007, Americans had 16 million pet birds (compared to 74.8 million dogs, 88.3 million cats, 142 million freshwater fish, 9.6 million saltwater fish, 24.3 million small animals, 13.4 million reptiles, and 13.8 million horses).

Finally, birds are a source of beauty and enjoyment, both in their form and color, and often, in their song.

Coming up

Guided Bird Walk, Saturday, Oct. 15, from 7 to 9 a.m., free, Audubon Greenwich, 613 Riversville Road, meet in the main parking area, 203-869-5272 x239 greenwich.audubon.org.

Trans-Pacific Migrations, talk by Peter Pyle of Institute for Bird Populations, Thursday, Oct. 13, 6:30 p.m., $10 adult, $5 kids, Audubon Greenwich, 613 Riversville Road,  RSVP 203-869-5272 x239 greenwich.audubon.org.

Hook Mountain Hawk Watch, trip to west side of Hudson, Saturday, October 15, 9 to 3, $15, Audubon Greenwich, 613 Riversville Road, RSVP 203-869-5272 x230 greenwich.audubon.org

Hawk Walk, hawk-bander Larry Fischer and bird expert Milan Bull from CT Audubon Society for a special hawk hike in the orchard, Sunday, Oct. 23, 9:30 to 11:30 a.m., Aspetuck Land Trust, at Trout Brook Valley Orchard, Easton, www.aspetucklandtrust.org, reservations at  This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Saw-whet Owl Banding in Mohonk Preserve, evening trip to New Paltz, N.Y. (transportation provided), Saturday, Oct. 29, 6 to 10 p.m., $50, RSVP to Luke Tiller ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it ). Audubon Greenwich, 613 Riversville Road, greenwich.audubon.org

Birding with Luke Tiller: Saturday, Oct. 29: Sparrow Big, 7:30 a.m.,  $10; to register visit www.sunrisebirding.com/walks.htm.

Sparrow Migration at Croton Point Park on the Hudson, with Bedford Audubon Naturalist Tait Johansson, Wednesday, Nov. 2, 7:30 to 11:15 a.m. Bedford Audubon, Jeanne Pollock at 914-519-7801, This e-mail address is being protected from spambots. You need JavaScript enabled to view it ,   www.bedfordaudubon.org.

“Magical Mystery Tour,” a “Leader’s Choice Bird Trip” with Bedford Audubon Society’s Tait Johansson and Nannette Orr, Sunday, Nov. 6, check for time, This e-mail address is being protected from spambots. You need JavaScript enabled to view it or  914-232-3334, www.bedfordaudubon.org.

Family Bird Watch & Project Feederwatch, how your family can be “citizen scientists” to help count winter birds at feeders in the backyard, Saturday, Nov. 12, 2 to 3:30 p.m., Audubon Greenwich, 613 Riversville Road, RSVP 203-869-5272 x221 greenwich.audubon.org

Jamaica Bay National Wildlife Refuge, with Bedford Audubon Naturalist Tait Johansson,  Tuesday, Nov. 15, 9 a.m. to 2:30 p.m. Depart Bylane Farm, Katonah at 7:45, call Jeanne Pollock at 914-519-7801 or email   This e-mail address is being protected from spambots. You need JavaScript enabled to view it .  www.bedfordaudubon.org.

Copyright 2011 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] gmail.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s website is www. sandersbooks. com.