CHAPTER 1

WHAT TO NOTICE ON A WARBLER

This section illuminates important warbler characteristics that can be used to significantlyaccelerate the identification process. There are five sections: Contrast and Color; Size,Shape, and Behavior; The Face; The Body; and The Undertail.

Section 1: Contrast and Color

Contrast One of the primary ways to separatewarblers is by contrast. The birds in the Visual Findersare easily separated into two categories: high-contrastbirds, which have bold markings and colors,and low-contrast birds, which are drab or plain.There are two basic types of contrast: tonal contrast,when adjacent areas are brighter and darker; andcolor contrast, where different colors intersect (forexample, black and yellow are highly contrasting, while yellow and olive are not). Thesetwo types of contrast are not mutually exclusive—often a bird with high tonal contrastalso has strong color contrast.

The well-defined, high-contrast throat of a Common Yellowthroat is especially distinctwhen color contrast is removed from the equation.

General contrast manifests in several ways on a bird, one of which is the contrast betweenthe lower body and the upper body and wings.

Hooding occurs when the head color contrasts with the body color.

Wing bars are created by white tips on the greater and median coverts and can be a strikingand very important ID characteristic. There are more subtle but equally importantcontrasting covert patterns in the wings that are also worth noticing.

Facial contrast is sometimes useful in separating similar birds. Townsend's and Black-throatedGreen warblers are similarly shaped; both have black streaking in the sides, ablack throat, and both are masked and capped. In fact, at first their faces seem very similar,but the degree of contrast becomes a key ID point.

Likewise, Orange-crowned and Tennessee are similar in structure and coloration. WhileTennessee has white undertail coverts and Orange-crowned has yellow undertail coverts,facial contrast can be a quicker way to separate them.

Many warblers have bright, contrasting facial features in spring that make them easy toidentify—Cape May, Blackburnian, Prairie, and Wilson's, for example. These same patternsare often present and equally diagnostic in the fall, but in a lower-contrast form.

Color One of the delightful things about warblers istheir color, which can quickly lead to an accurate identification.Note, however, that more than half of the warblersin this book lack any really distinctive colors, so itis also important to be aware of qualities like contrastand shape, and markings like wing bars and streaking.

Diagnostic colors occur on a few birds and can lead to an instant ID.

It is often helpful to think of not one color, but rather of a combination of colors, becausecertain color combinations are sometimes unique to a species.

For many species it's important to notice subtle variations of color.

Subtle color differences can be an excellent starting point for identification.different types of blue here in four species of warbler:

Lighting conditions can strongly affect a bird'sappearance. At sunrise or sunset, all birds seemwarm, with unexpected yellow or pink tones.

Section 2: Size, Shape, Habitat, and Behavior

Before focusing on the specifics of plumage, it is a good practice tolook at size, shape, and behavior. Like a sculptor starting with ablock of marble, it is critical in identification to work on the mostgeneral characteristics first and then proceed to the fine details.

Size Size is especially useful for separating warblers from other species, such as largerorioles, tanagers, and vireos. The following silhouettes are shown in accurate proportionto each other.

Many warblers are of similar size: small warblers are around 4.5 in. long, average-sizewarblers are around 5 in., and large ones can be 5.5 in. or larger. Sometimes these sizedifferences can help differentiate similar warbler species without one ever having to gointo plumage specifics. Note that size is often noticed through a bird's movements: largerbirds tend to be slower moving, while very small birds are often quick and flitting.

Shape Like size, shape is most important when separating warblers from other nonwarblerspecies. The following silhouettes are all sized the same (despite different actualsizes) to emphasize the differences in shape.

Differences between warbler shapes can be more subtle. Differences do exist, though, andwith careful attention these can be quite useful.

Similarities are also notable: many closely related warbler species are similarly shaped.

Habitat is useful in terms of probability. A warbler high in a tree is most likely not aCommon Yellowthroat (although it can occur there), and a warbler walking along astreambed is unlikely to be a Cerulean.

Behavior is an excellent starting place in identification. Non-warbler species often behavequite differently from warblers, and some warbler behavior is diagnostic.

Section 3: The Face

Almost every warbler in North America can be identified byface alone. The more sensitive your eye becomes to facial marks,the better able you will be to ID warblers, especially when onlypartial views are available. This section addresses cheek patches,masks, eyerings and eye-arcs, superciliums, top-of-head markings,bills, and throats.

Cheek patches, or auriculars, are contrastingly darker areas behind and below the eye.

Masks and other black facial marks are found on about a third of the warblersdiscussed in this book, often providing distinct ID points.

These four "black-throated" warblers each have distinctive facial markings.

Eyerings and eye-arcs are the circles or partial circles around some warbler's eyes.

These three elusive, ground-dwelling warblers are separable as adults by their eyerings,eye-arcs, or lack thereof.

In each of these pairs, the eyering helps separate two similar warbler species:

In these examples, the eyering merges with the supraloral area to create a "goggled" effect.

Eyelines are dark lines through the eye, often extending on both sides.

Some drab fall warblers have differences in their eyelines, which contribute to differentfacial expressions:

Lores are partial eyelines in front of the eye, and post-ocular lines are partial eyelinesbehind the eye.

The supercilium is a light contrasting area above the eye that often creates an "eyebrow"effect.

Top-of-head markings Capped, hooded, and striped are terms for the contrastingcolor area on top of some warblers' heads. Hooded birds have a colored head that contrastswith the body, capped birds have a dark upper head that contrasts with the face,and birds with striped heads have contrasting lines on their upper head.

Each of these colored caps is distinctive.

Bills vary among warblers, especially across genera. For example, warblers in the genusGeothlypis, which includes Mourning, MacGillivray's, and Kentucky, all have relativelylarge bills. Vermivora and Oreothlypis (until 2010 considered the same genus)—Golden-winged,Blue-winged, Lucy's, Colima, Orange-crowned, Tennessee, Virginia's, and Nashville—have fine, pointed bills.

Bill shape and size have a lot to do with the feeding habits of birds. Mourning, MacGillivray's,and Kentucky feed on invertebrates on the ground and like to probe and pushaside leaves, hence their heavier bills. Vermivora often glean insects from bark and nectarfrom flowers hence their fine, pointed bills.

Bill size can be tricky to differentiate on similar warbler species (especially in the largegenus Setophaga), and it is often more of a supporting feature. Some species, however,have bills that are noticeably different.

Bill color may vary in some warblers depending on age. In a couple of species, the bill isdistinctly bicolored: black on top and pale on bottom.

Bill shape and size contribute to a warbler's silhouette and general appearance and provideexcellent separators to differentiate a warbler from other types of birds such as vireos,flycatchers, and orioles (see the section Non-Warbler Similar Species for more detailson these birds).

The throat is the transitional area from below the bill to the top of the breast.

Throat streaking can be useful in identifying Cape May and the waterthrushes.

Throat color is most helpful for ID purposes when it strongly contrasts with the rest ofthe head. For example, a strongly contrasting black throat narrows the ID choices to asmall group of warblers:

The malar stripe is the contrasting line that runs from the base of the bill to the top ofthe shoulder along the side of the throat.

Section 4: The Body

Warblers are often seen in partial view, and knowing the specificsof body topography can often be an important advantage inmaking an ID. To that end, this section addresses the breast,belly, and flanks; the back and rump; and the wings.

The breast, belly, and flanks make up the underbody of awarbler between the throat and legs. The breast is the "chest"of the bird, and the flanks are the sides below the wings andabove the legs on a standing bird.

Body streaking can be important in ID.

Streaks can be closely spaced (dense) or widely spaced (sparse), and they can be evenlydistributed or clumped.

Only a few warbler species have colored streaking (not brown or black) on their breast,which is always diagnostic.

Necklaces are a pattern of streaking across the breast, which can be an important IDmark. Notice the full or partial necklace effect in these birds:

Side stripes are a very important ID point shared by three warbler species. Such stripesconsist of a single, thick band of color than runs along the side and flank.

Color of breast and flanks is sometimes diagnostic.

The extent of breast color and how it blends with adjacent areas is important.

The back and rump are the upper parts of the bird. The back color can bleed into thehead and rump or can stand out on its own.

Back streaking occurs in many warblers.

Patches are squares of contrasting color on the center of the back found on a couple ofwarbler species, and can be diagnostic.

The rump is the lower back, above the base of the tail. For many birds the rump is thesame color as the back, but a few have a contrasting rump color.

Not all rump patches are created equal. While some species have small areas of stronglycontrasting color, others have a more diffuse patch that extends all the way across thelower back. Diffuse patches are often overlooked but can be important ID points.

Wings often have contrasting wing bars created by the contrasting tips of the greater andmedian coverts.

It can be very useful to notice the color and contrast of the area between a bird's twowing bars.

Wing panels occur when the pale covert edges are more extensive, causing the wingbars to become a solid block of color, and are found on breeding-season males in somespecies.

One species shows a more restricted patch, created by white bases of the primaries. Commonlyreferred to as a "handkerchief," it is not found on all individuals (specifically somefirst-year female birds), but it is diagnostic when present.

Flight-feather edging is a subtle but useful quality on some warbler wings and can becontrasting, colored, or both.

Primary projection is how far the tips of the folded primaries extend past the tertials onthe folded wing (see diagram in Topographic Tour). In other types of birds, such as shorebirdsor flycatchers, the primary projection can be very useful for ID. On warblers, however,it is only regularly useful in a few ID problems, two of which are Blackpoll andBay-breasted Warbler versus Pine, and Tennessee versus Orange-crowned.

The contrast between wing color and body color is also useful at times. One subtleexample is the bluish cast of the female Wilson's warbler's wing contrasting with its bodyand back, unlike that of Yellow or Hooded warblers.

Section 5: The Undertail

Even from high overhead, warblers offer many important clues to their identity throughthe undertail. When a warbler is perched on a twig or branch, the main view offered isoften from the legs back to the tail. This view shows the warbler's lower breast, vent,undertail coverts, and folded tail. In combination these areas offer important ID informationthat can be diagnostic or at least conclusive when combined with one or two otherpoints such as throat color. In this section we cover what to look for in each of these areasand how to use them as a group to help identify a warbler.

A few cautionary notes about looking at warblers from below. First, be aware of lightingand shadows, because they can have a powerful effect on a bird's appearance.

Second, birds do not always hold their tails neatly, and this can make them look very differentfrom their "normal" pattern.

Finally, in some situations molt can causethe tail to look odd.

The belly is the area just in front of the vent. We will only consider a small portion ofthe very bottom of the belly. Of course, the full body color offers more clues, but oftenthis full view is not available.

The vent is the small area between the legs, below the lower breast and above the undertailcoverts. It often has more "texture" or fluffiness than the belly feathers or undertailcoverts. In general, the color of the vent blends into the color of the belly, but there areuseful exceptions.

Undertail coverts are multiple rows of feathers extending from the vent: the lowermostcover the base of the tail. The length and color of these feathers is often important.The length of the undertail coverts (abbreviated "UnTC") greatly influences how we perceivethe overall length of the tail from below. For tails of the same length, long undertailcoverts cover more of the tail and make the tail seem shorter, while short undertail covertscover less of the tail and make it appear longer.

Some undertail coverts have unique patterns that are diagnostic.

Tail characteristics include length, color, width, and extension past the undertail coverts.Each of these can help distinguish among warbler species, as well as separate warblersfrom non-warblers.

The tail extension when seen from below is the length of the tail beyond the undertailcoverts. Here, Blackpoll (and Bay-breasted) are easily differentiated from Pine by the tailextension: the long undertail coverts and long wings of the Blackpoll emphasize the short-lookingtail, while Pine has a much longer tail accentuated by relatively shorter wings.

Tail extension versus undertail covert length is often an important comparison.

Outer tail feathers When looking at a tail from below we see the two outermost tailfeathers, which are folded under the rest of the tail feathers. The apparent color of the tail,then, depends on the coloration of these outer tail feathers.

Tail color on warblers falls into four basic categories.

All-dark tails in warblers are usually not black but, rather, some shade of gray. Dependingon the light, these tails can range in appearance from near-black to light and silvery.They never look really white, unlike tails with white spots or all-white outer feathers.It's important to become sensitive to this difference, as casually identifying a silvery tailas white can lead to misidentifications.

All-white or white with dark borders occur if the outer tail feather is all white or nearlyso. Some tails look completely white, but others have a black or dark edge, particularlyat the tail corners. Some species, such as Hooded Warbler, flash the white of their outertail feathers in a distinctive way.

Dark with white tail spots is the most common configuration. From below, the tail lookspartly white, with the patches of white surrounded by dark.

Palm Warbler has very little dark on the tail edges but boasts a wide, square area of blackat the base of the tail. This is the nearly reverse of the Magnolia Warbler's tail pattern andis also diagnostic.