PRIMER #2 ON BIRD ID (5/25/01)

In my last column, I covered the basics of how to assess a bird — its size, shape, posture and behavior. Once you have run these specs through your mind, it’s time to turn to an up-to-date field guide, such as those by Kaufman, Peterson, Stokes or the National Geographic, although I strongly recommend that neophytes use a guide that is geared strictly to their area of the country. The guides that cover the whole United States can only make your task more difficult.

I also would discourage anyone from trying to use what is generally called a “coffee-table book” or from using a guide that organizes birds by their colors. The former cannot begin to give you the necessary information, and while the latter may seem logical to a beginner, you’ll have to trust me when I say that it’s not the way bird identification really works.

The primary purpose of a field guide is to describe both graphically and verbally those distinctive features that set one species apart from another. These are called the field marks of a bird. Let’s assume that you have a puzzling bird. You’ve already noted its size, shape, patterns on breast, etc. Depending on your experience with birding, you may at this point have an indication of its family. The type of bill is often an easy hint. However, if you are clueless, this is a good time to get acquainted with the arrangement of the field guide.

Although greater scientific understanding of the evolution of bird species is under continuous review, reliable field guides present birds in order of their evolution, the earliest, scientifically speaking, to the latest. So, for our area of the world, loons and grebes, followed by other water birds, are at the front of a field guide, while sparrows and finches are at the end. It helps to become familiar with this arrangement so that you can search quickly through the guide for that unknown bird.

Understanding the commonality of a family, such as thin bill vs. chunky bill, ground feeder vs. tree forager, and so on, will aid you in your identity search. Once you think you are in the right family, you’ll probably begin by looking for a picture that matches your sighting. However, a picture alone often does not provide the essential information. The other features of a field guide —the text and range maps — are important keys to successful identification but are the ones most often overlooked or ignored by beginning birders.

The text gives verbal descriptions of each species, including those of female and immatures. If there is another species quite similar, a guide will describe and compare them both. Field guides also indicator the important behavior characteristics of a bird. Do not dismiss these, as they are quite relevant to pinning down a bird’s id.

A sense of bird’s seasonality is equally essential when making its identification. For instance, seldom does a bird that should have returned to Latin America in the fall spend its winter far to the north of there, nor are birds that should be nesting in Canada likely to be in your yard in the summer. There are always exceptions, of course, but it’s best to start with the norm.

Equally important are the range maps. Assume that your mystery bird is in its usual range, so if you are somewhere in the East, rule out birds that live in the West. Yes, now and then, a bird does stray far beyond its normal range, but carefully rule out everything else first. If you pay attention to all these details, you’ll be unlikely to confuse warblers with sparrows. You will never, for instance, see a flock of warblers on the ground, and you’d know that sparrows in trees seldom flit around the way warblers would. A short-cut to identifying birds is to join a bird walk. The leaders are knowledgeable and can be a great help when you are learning about birds.

When it comes to identifying hawks, especially those in flight, one of the most important factors to consider is the time of year. The large hawks, called Buteos, often drift overhead without flapping their wings while they ride an updraft of warm air, known as a thermal. They sit on the top of telephone poles or on a bare branch of a large tree, but separating them by species is not easy. If you see the red tail on an adult red-tailed hawk, one of the most common hawks in these parts, you don’t have to look any further. However, not all red-tails have red tails.

This sort of conundrum is why you turn to your field guide. Although red-tails do migrate, on Cape Cod they are with us year around and are often harassed by crows. Their screaming kee-aah is often a help in confirming identification. Red-shouldered and broad-winged hawks nest more commonly on the mainland than on the Cape, although a few migrate over the Lower Cape. In the winter, rough-legged hawks may appear from the North, but don’t consider that species after April when trying to make an identification.

Another family of hawks is the Accipiters. The sharp-shinned and Cooper’s are the ones that frequently raid our bird feeders during the winter. They fly with a flap, flap sail and are smaller than the Buteos. Field guides describe plumage and behavior better than I am going to attempt here. The last family of our area’s hawks are the falcons. The smallest, the kestrel, is not numerous on the Cape. It is most usually seen perched on telephone wires and is quickly identified by its strong “sideburns.” Peregrine falcons migrate through here and nest on tall buildings in the state’s cities.

By the way: Were you able to identify Joyce Leary’s bird photo in my last column? It was a female Baltimore Oriole. Did you recognize this week’s graphic? It's a female Rose-breasted Grosbeak, a fairly abundant bird this spring at people's feeders.