A Guide to the Guide
How To Make This Book Work For You
There is nothing particularly complicated about a guide to bird identification. All it is (or hopes to be) is a book that explains what to look for to distinguish one species from another. In addition, both directly and indirectly it tells you how to go about doing so. For this book to work for you, you don’t need to know any more than this. All you have to do is turn to the account of a species of interest. Read the text. Bring the information to bear in the field, or in the case of a bird you’ve already found and studied, compare the text to the details housed in your memory (or inscribed in your field notes) and see whether you have a match.
But if you want to maximize the potential of this book, and if you are the kind of person who is interested in the whys as much as the what and the how, then you are invited to keep reading. Certain principles govern the information provided here and the manner in which it is presented. If you understand these principles, this book will serve you better.
First, insofar as this book is designed to be a supplement, it is presumed that you already have one or more of the standard illustrated field guides to birds at your disposal. As they have been since the publication of the seminal Peterson field guide in 1934, a basic field guide is every birder’s primary resource when confronting an identification challenge. This book is meant to augment these primary guides by offering more information. It also strives to present information as naturally as possible by replicating the identification process used by an experienced birder: looking at the big picture first and sleuthing for details later.
Inexperienced birders commonly use field marks to jump-start an identification. Experienced birders use field marks to confirm it. For very understandable reasons, standard field guides are thematically allied to the jumpstart school. This guide is more wedded to process.
Don’t Keep an Open Mind
Even before they sight a bird, experienced birders are bringing their experience to bear. They know that birds are creatures of habit and habitats and that the nature of a habitat encourages certain species to be there and discourages the presence of others. For example, you would expect to find a Carolina Wren in a suburban, coastal community in New Jersey. You would not expect a Rock Wren, a bird common to arid, rocky slopes.
Also, experienced birders know that different bird species have defining ranges (Rock Wrens are western birds that are not found east of the prairies, so they are not likely to be found in New Jersey) and that a bird’s range is determined not only by geography but by seasons. The range of Rock Wren extends into southern British Columbia, southern Alberta, and southwestern Saskatchewan in the summer, but in the winter northern breeding members of this species retreat farther south. This species is not located in Canada in winter.
So when these birders go birding, their accumulated knowledge and experience enable them to predict which birds they are likely to encounter based on location, habitat, and time of year (among other clues). And because they are able to go into the field juggling fewer variables, the identification process is greatly simplified for them.
When a wrenlike bird pops up on a scree slope in June in the Rocky Mountain foothills just west of Calgary, Alberta, they can test a hypothesis Is it Rock Wren?” (the expected species)rather than approach the problem by asking: Now, which one of the nine species of wrens found in North America is this?” But, you may be saying, I’m not an experienced birder, so I cannot apply such a search engine to filter what I see. That is exactly the function of the introductory paragraph in each species account.
Identification Right Think
The introductory paragraph for each species provides a biographical backdrop. The elements include STATUS, DISTRIBUTION, HABITAT, COHABITANTS, and MOVEMENTS/MIGRATION. STATUS relates to the bird’s numeric abundance and condition of residency (whether it is a permanent resident, a summer or winter resident, a visitor, or a vagrant). You are likely to see birds that enjoy large populations and less likely to see those whose populations are small. The terms common,” uncommon,” and rare” are most commonly used to describe a bird’s status. A common” bird is one you are very likely to encounter; uncommon” refers to the bird you might see, but perhaps another, similar (and perhaps more common) bird should also be considered as a candidate. Rare” birds are the ones you have only a slim chance of encountering. If you encounter a bird that reseembles a rare species, your identification may well be correct, but you should approach the possibility with caution.
DISTRIBUTION defines the geeeeeographic area in which the bird is typically found. For some species, this remains fixed all year. For other species, distribution shifts seasonally. HABITAT describes the biological settingclimatic, topographical, and vegetativethat the species favors and offers examples of such settings. COHABITANTS are the other birds (or animals) that are also specialized for and likely to be found in a bird’s preferred habitat. MOVEMENTS/MIGRATION provides the dates (and sometimes the routes and key staging areas) a species moves between its breeding and wintering areas; this passage sometimes carries the bird across regions that do not fall within that species’ breeding or winter range.
Taken in sum, STATUS, DISTRIBUTION, HABITAT, COHABITANTS, and MOVEMENTS/ MIGRATION constitute the biological framework that defines where a bird is likely to be and when it is likely to be thereand thus whether a species is likely to be what you believe it to be.
In a word, these elements of species’ biographical backdrop define probability. Experienced birders use probability all the time, and inexperienced birders eventually come to appreciate it. They also come to understand that probability is not confining and in fact is empowering. It helps turn a complicated question (Now, which one of the 800 species of birds found in North America is that?”) into a simple one (Is this the species I expect?”).
You’re in Cape May Point, New Jersey. You see a large wren in a suburban yard. The question you’ll ask is: Is it Carolina Wren, the default large wren for the region? Almost always the answer is yes. But as salient a factor as probability is, it is not determining. It suggests, but it doesn’t certify. Probability has a qualifying companion called possibility. Birds don’t always follow the rules. They sometimes turn up outside their prescribed ranges and in marginal or ill-suited habitats or at odd times. Getting back to the aforementioned Rock Wren, it so happens that in December 1992 a Rock Wren was found in Cape May Point, New Jersey, rummaging around in the scattered debris of a house under construction.
So the last piece of information imparted in the opening paragraph, designated VIshort for VAGRANCY INDEXis a conditional modifier. This index relates to the known vagrancy tendencies of a species or the possibility that it may turn up where it doesn’t belong (in terms of its normal geographic distribution). There are five ratings.
0 No pattern of vagrancy. The chances of this species being seen outside its range are scant to nil.
1 Some slight tendency to wander, but such occurrences are regional, extending not far beyond the established borders of the species’ range, or there are simply very few records of vagrancy.
2 The species shows some modest pattern of vagrancy. It is possible to encounter it outside its normal range but still not likely, and you should consider other, more likely possibilities first.
3 This species has demonstrated an established, widespread pattern of vagrancy. Ignore the range descriptions. This bird could be sighted almost anywhere.
4 The species is so widespread that there are few places left in North America for it to wander.
If you don’t care to remember the particulars, just remember the rating system. The lower the number, the less likely a species is to wander.
Birds Are the Sum of Their Parts (and More), or, But How Did You Know It Was a Wren and Not a Swan?
The field marks used to differentiate birds relate most often to structure and plumage. Used in concert to make an identification, both are important. But a bird’s structural characteristics are in many ways more fundamental and more determining. More than plumage, structural attributes (such as bill shape, neck length, body shape, leg length, or foot shape) link birds to closely related species; also, because these attributes vary less between the ages and sexes within a species, they are commonly not as variable or transitional as plumage. Accordingly, the description for every species looks first at structure and concludes with plumage, focusing first upon the most fundamental traits.
SIZE AND OVERALL SHAPE: Birders argue as to whether size or shape is a bird’s most determining characteristic (the one experienced birders note first when making an identification). The fact is that most birders see and assess these qualities simultaneously, thus quickly simplifying the identification process.
STRUCTURAL CHARACTERISTICS: Bill size, shape, and length, head size and shape, the contours of a bird’s neck, the shape of its body, the length of its legs, the shape of its feetall constitute important, determining structural characteristics. These morphological traits divide birds into groups, such as sandpipers, hawks, gulls, warblers, or finches. Plac...