Articles & Resources

Anatomy of a Bird
By Maria Stockmal

If you own a bird field guide I hope you read the Forward, the Preface, and the Introduction. There is a great deal of good information in these pages to help any birder, beginner, casual, or expert, to learn or review basic bird anatomy and generalities. In addition, some guides will add information or tips on bird songs, nests, maps, habitats and identification.

Although each field guide is unique in its approach to teaching about birds and bird identification, they will all include a drawing of the anatomy of a bird. This anatomy illustration can be very helpful in identifying birds.

The head of a bird is divided into several parts. The head has a crown, forehead, mandible, chin, throat, auricular (ear), and nape (collar). A birder would examine these areas for color, shape, and size. This would tell the birder something about the bird. For instance, a small head would lead a birder to think of the size of a sparrow but a larger head would lead a birder to think of the size of a robin - a five inch bird vs. a nine inch bird. Also, the colors on the head would also lead the birder to think of specific families of birds. Birds with black heads may be blackbirds (Icteridae) and birds with brown heads may be thrushes (Turdidae).

The legs of a bird are separated into tarsus, the leg part, and toes. Birds also have a breast, shoulders, may or may not have wing bars, side or flanks, belly, rump, and back. Its feathers are identified as primary feathers or flight feathers, secondary feathers, scapulars, upper tail coverts, under tail coverts, and outer tail feathers. The parts of the body can be even more specific and depending on the field guide some parts stressed more than others.

Connecticut Warbler (Oporornis agilis)	Mourning Warbler (Oporornis philadelphia)
Photos courtesy of www.avesphoto.com

To differentiate between birds within one family, more specifics are needed. The bird could have an eye ring, a supercilium (eyebrow), an eye line, and/or a mustache (malar). The difference between a Connecticut Warbler (Oporornis agilis) and the Mourning Warbler (Oporornis philadelphia) is that the agilis has a complete, circular eye ring and the philadelphia does not. Otherwise, both birds are similar and could be misidentified upon initial sighting. It is also interesting to note that wings on birds have wrists. This is something we wouldn’t think about but when watching hawks fly, the Sharp-shinned Hawk (Accipiter striatus) can be identified from the Cooper’s Hawk (Accipiter cooperii) by the movement of its wrist.

When buying a field guide, examine the introduction and see what additional information is provided. I own several field guides and each reveals different information in the introduction as well as throughout the book. Cross-referencing has helped me positively identify many a difficult bird in the field.