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Prime Time: An oversized field guide worth having anyway

Q. When is a field guide not a field guide? A. When it's too big to go in a cargo pants pocket.

Despite that, I bought one last fall, as sort of a birthday present to myself, and I'm glad I did.

Since the '30s, Roger Tory Peterson's field guides to birds have been standards against which to compare others, and I have generally preferred both of them to later competitors. In some ways, I have also preferred earlier editions to more recent ones. The older ones had descriptions with some natural history, and colored plates distributed throughout the books. Back then, color was a big deal, and was expensive. Recent technology has made color more affordable, and the books are glossy throughout, with paintings on the right (recto) and descriptions to their left (verso). One result is less natural history.

The major disadvantage to Peterson guides to North American birds (north of Mexico) required the "both of them" above. There are two guides, Eastern and Western. When Elaine and I went west, we had to buy a second book. If you wanted to look up birds in general at home, you needed two books. Another disadvantage to early Petersons was that ranges were described; there were no maps.

Competing guides have appeared, mostly as single volumes for all of North America north of Mexico. Some have tiny range maps of the whole continent by each species account. In 1980, a new Eastern Peterson appeared with large maps, 6 to a page, in a separate section at the back, and with some revised illustrations. Particular paintings in other guides may be better, but I think Peterson's are most successful overall. Some guides use photos, but they are seldom as helpful as paintings for field identification. Some people complain about Peterson's locating maps at the back, separate from the illustrations.

Peterson died at 87 in 1996. The new (2008) "Peterson Field Guide to Birds of North America" contains much original material from the latest Eastern and Western guides, plus new material contributed by his son Lee Allen Peterson and several others. It is bigger, has many new illustrations plus slightly- and well-modified older illustrations, and solves the map location problem. There are small maps by each species, but also larger maps at the back.

The inside front cover of the new book has a continental map showing how winter, summer, and open sea ranges are indicated. The first page is a one-page index indicating first occurrence of broad categories (e.g., "Gull, 184", "Swift, 252). The Contents pages are color-coded to colors at the bottom of the verso pages indicating, again broad categories, not always corresponding to a single taxonomic group (e.g., swifts and kingfishers), but corresponding to the sequence in the main text.

The introduction is mostly Peterson's own useful illustrated discourse on how to identify birds. The bulk of the book is recto plates opposite verso species accounts. The sequence differs much from what you may be used to. The first groups in most guides for decades have been loons and then grebes. Now it's geese, swans and ducks, then chicken-like birds (pheasants, grouse, and such). What happened?

First, remember that a book or a list has to be linear. But the relationships within groups of organisms are a branching phylogenetic tree of some sort. Of course, a field guide to living birds includes no long-extinct groups. But recent research, mostly molecular, has refined our knowledge of relationships, and it turns out that ducks' ancestors branched off earlier than loons' ancestors. It also turns out that a book is soon out of date. You may remember my June 2002 article announcing that New World vultures were more closely related to storks than to hawks, falcons and Old World vultures. DNA work has cast serious doubt on that, but this 2008 book was compiled too soon to catch the revision, and still places them in the same order as the storks.

The bulk of the book does not list orders, just families plus the Latin and common names of species. But there is a "life list" at the back after the range maps, where you can record the date you first saw a species. That is arranged by orders and families as recognized in 2007 by the American Ornithologists' Union. (The current list is at ).

Having (Eastern) maps in the 1980 guide to compare with continent-wide 2008 maps is instructive. One of the most striking shows that the house finch, a western species unfortunately released in New York in 1940, has blanketed all of the contiguous states and adjacent southern Canada. Sad.

EVAN HAZARD, a retired BSU biology professor, also writes "Northland Stargazing" the fourth Friday of each month.