How to identify specimens (by Brian O'Shea)

On your lab final you will be asked to identify specimens of about 25 of the ~230 species that we have covered in lab thus far. Some of these may be familiar from field trips, but most will not. The purpose of this guide is to attempt to facilitate your acquisition of techniques to help you separate the various families and species from one another in a systematic fashion. Remember that not all field marks depicted in guides will be visible or useful for identifying stuffed specimens. This guide focuses on features that you can assess easily on a study skin.

Imagine this situation. You are presented with a specimen and asked to identify it. Your first impression is that the bird is kind of small, with an insectivore-type beak. It is greenish, with some yellowish, and no markings on the underside, but it has a thingy near the eye. You start to panic and ultimately scribble something, hoping that I can't read it but will somehow give you the benefit of the doubt. That will not happen. You need to have a systematic way to narrow the possibilities, because there are many greenish-yellowish birds with some kinds of markings and thingies in various places.

When ornithologists view a specimen, they immediately evaluate the bird's "general impression". This is a subconscious, reflexive action that usually results in the bird being placed to family or species almost instantly (after a brief confirmation of diagnostic features). You will need to duplicate this process (at a slower rate, perhaps) for the specimens on the lab final. This is how it's done.

Step 1. Predictive morphology

First, look at the bill, wings, tail, and feet to determine if they fall into any of the predictive categories that we have covered in lab. Keep in mind that these categories often complement one another: for example, a bird with a climbing/bracing tail is more likely to have "tree-climber" feet than webbed feet. If you can place at least one feature of the bird into a predictive category, and you know roughly which families/species do the behavior indicated by that category, you have already eliminated a large portion of the possibilities.
In many cases, however, the bird's morphology will not give you much if any predictive information (which is the case with many of the Passeriformes), or you will have several options within a predictive category. You must then move on to examine some of the bird's finer features.

Step 2. Unusual field marks

The second step is to evaluate whether the bird has some unusual color or pattern. This is a pitfall for many people, because they tend to dwell on one specific color and try to categorize birds by their dominant color(s). This doesn't work for the most common colors in birds ­ namely, green, yellow, brown, black, and white. The plumage of many birds is a combination of two or more of various shades of those colors. Calling something a "brown bird" isn't going to get you very far if you don't know how to tell which "brown bird" it could be. In such a case, stand back and move on to the next step. Fortunately, unusual plumage colors do exist, and it should be fairly easy to distinguish the species that sport such colors. For example, if a bird is black, white and orange, it is one of three species: American Redstart, Baltimore Oriole, or Blackburnian Warbler. The lists of species with lots of red or blue plumage are similarly short. These species should be "no-brainers"; learn them and get them out of the way. If you can't identify a Roseate Spoonbill, you can't graduate.
A similar approach can be taken with pattern. For example, few species are entirely one color ­ learn those species. The triangular red patch on the breast of a male Rose-breasted Grosbeak is unique among Louisiana birds. So is the yellow tail-tip on a Cedar Waxwing. Most ducks have a diagnostic facial pattern. Other features, such as streaking or wing bars, are common to many birds, so learn to ignore those at first. Focus (briefly) on anything that stands out as somehow unusual, color- or pattern-wise.

Step 3. Determine family

You're still stuck with your greenish-yellowish eye-thingyed thing. By this point you have determined that it has an insectivore bill, but that doesn't help you much. You're fairly confident that it belongs to one of the families in the Passeriformes, so the next step is to determine which one. This is the third step ­ get it to family. You should know how to tell a warbler from a vireo, and both of these families from a thrush. Half of your points on the identifications will come from your placement of a specimen into the correct family or order. See the Appendix for some common cross-family mistakes.

The number-one clue for family ID is the bill. Know your bills. This alone will give you a big advantage in placing a bird in the proper family. True, the "standard insectivore" phenotype is rather plastic, but variation within families is quite small, and hopefully you'll move on to other diagnostic/confirmatory features without really noticing that you checked the bill at all. In any case, you will probably cue in on the bill relatively early in the identification process, not only because it is part of Step 1, but because people tend to focus on facial patterns; this is a good thing, as described in the next step.

Step 4. Facial recognition

Assess the bird's facial pattern. Learning birds is a lot like learning to recognize people's faces. It is absolutely essential that you be familiar with the various topographic regions, especially those of the head. This applies to birds in general and Passeriformes species in particular. Know the difference, for example, between an eye line and an eye ring -- and, within a family, which species have them and which don't. Know where the lores are relative to the forehead. Note any contrasting pattern (many warblers have diagnostic head patterns). If the bird appears "plain-faced" (i.e. does not have any obvious markings), this too can be a useful clue to identification.
Going over some of the "challenging" species pairs given in the Appendix, and learning to quickly distinguish one species from the other, will help clarify your understanding of topographic regions and their use in identification.

After suppressing your fifth panic attack of the day, you have taken another look at that confounded yellowish thingy. Its standard insectivore bill is on the skinny side, the bird itself is rather small, and the facial pattern is prominent; on the basis of these features you decide it's a warbler (Parulidae). You remember that many warblers are some combination of green and yellow, so your confidence rises a bit. Looking at the face, you note that what was once a "black thingy near the eye" can more accurately be described as a patch of black that extends across the forehead, totally encompassing the eye and extending onto the auriculars. You now have a pretty good idea of what this bird is, but before you write anything down, you need a final confirmatory clue. Which brings you to step 5.

Step 5. The underside

Look at the bird's ventral surface. Is it spotted? Streaked? Barred? Does it have any unusual pattern or features (e.g., pink hearts? Orange stars? Purple horseshoes?) Again, it is imperative that you know the topographic regions ­ for example, sides vs. flanks, etc. Where are the markings? ­ this is probably most important. Are they confined to the breast? Extending from the sides onto the flanks? Is the underside completely unmarked? Is there contrast in color between the throat and breast, or breast and belly? Are there patches of color anywhere?

Almost as soon as you saw your quiz bird, you casually registered something that fits each of the steps above (except Step 3) ­ generally small, with an insectivore beak but no other good predictive info, hence the panic (Step 1), greenish-yellow coloration that didn't strike you as particularly unusual, let alone diagnostic, hence continuing panic (Step 2), eye-thingy (Step 4), unmarked ventral surface (Step 5). Gathering yourself a bit, and remembering some of the tips we'd given you for identifying various families, you correctly guessed (perhaps) that it belongs to the Parulidae. Step 3 accomplished retroactively. This is very likely how you will approach most of the specimens during the lab final ­ whether you know it or not, you will look at the face (because everyone does) and the ventral surface (because it will be facing up). The key is to recognize how you're processing the information that is presented to you in the form of a dead bird, and to eliminate panic by systematically reducing the possibilities of what that bird could be.

At long last, you have taken a good look at your quiz bird's underside, and noted the complete absence of markings on a yellow breast contrasting with a white belly. This could mean only one thing ­ Common Yellowthroat. You jump up on the table and roar in triumph. Years later, reflecting upon that jubilant day, you suddenly realize that you actually made things far too hard on yourself . . . No other small, greenish-yellow bird in Louisiana has the "mask" of the male Common Yellowthroat. Unusual pattern. Step 2. You vow to re-read your Sibley Guide cover to cover.

Hopefully this guide will help you make sense of the many families and species of Louisiana birds that you have to know for your lab final. More importantly, we hope that learning to identify these species will foster an appreciation for the avian diversity of Louisiana (remember that there are ~150 species occurring here that we didn't cover in lab) and encourage you to spend more time outside enjoying birds.

Finally, a disclaimer: not all birds will be safely identifiable by strict adherence to my 5-step program. Some degree of familiarity with every species covered in lab is essential for a perfect score.

Reading material

The following references should be in the library and may be useful:

Dunn, J.L., and K.L. Garrett. 1997. Warblers (Peterson Field Guide Series). More warbler illustrations than you will ever want to see, but gives you a good feel for variation within species.

Peterson, R.T. A Field Guide to the Birds (Eastern). I learned birds as a young kid with the Peterson guide, and I still think that it is the best one out there for beginners. The plates are straightforward, with minimal clutter, and arrows point straight to the key field marks.

Rising, J.D. 1996. A Guide to the Identification and Natural History of the Sparrows of the United States and Canada. In-depth sparrow coverage.

There are a multitude of similar guides and reference books for individual families; check the library, they should all be in the same section.

Appendix

"Challenging" species

This list is intended to give you a "heads up" so you are prepared to confidently resolve common identification dilemmas, should they face you in the near future. I am only listing easily confused species pairs or groups; it's up to you to remember how to separate them.

** Note: Selection of bird species for the lab final is a computerized, random process. These species are no more or less likely to appear on the exam than any others. **

Ring-necked Duck vs. Lesser Scaup
Snow Goose vs. Ross' Goose
Redhead vs. Canvasback
Bufflehead vs. Hooded Merganser
Black vs. Turkey Vulture
Sharp-shinned vs. Cooper's hawk
King vs. Clapper Rail
American Coot vs. Common Moorhen
Semipalmated vs. Piping vs. Snowy Plover
Black-bellied vs. American Golden Plover
Greater vs. Lesser Yellowlegs
Spotted Sandpiper vs. Sanderling vs. Dunlin
Western vs. Least vs. Pectoral Sandpiper
Long-billed Dowitcher vs. Wilson's Snipe
Herring vs. Ring-billed Gull
Royal vs. Caspian Tern
Mourning vs. White-winged Dove
Inca Dove vs. Common Ground-Dove
Chuck-wills-widow vs. Whip-poor-will
Common Nighthawk vs. Eastern Screech-Owl
Downy vs. Hairy vs. Red-cockaded Woodpecker
Pileated vs. Ivory-billed Woodpecker
Eastern Kingbird vs. Black-billed Cuckoo
Eastern Wood-Pewee vs. Acadian Flycatcher vs. Eastern Phoebe
Northern Rough-winged Swallow vs. female Purple Martin
American vs. Fish Crow
Vireonidae vs. Parulidae
Yellow-throated Vireo vs. Pine Warbler
Winter vs. House Wren
Loggerhead Shrike vs. Northern Mockingbird
Brown Thrasher vs. Wood Thrush
Hermit vs. Swainson's Thrush
Regulidae vs. Parulidae
American Pipit vs. other streaked, brown birds
Tennessee vs. Orange-crowned Warbler
Blue-winged vs. Pine Warbler
Blackpoll vs. Black-and-white Warbler
Yellow-throated vs. Blackburnian Warbler
Northern vs. Louisiana Waterthrush, and waterthrushes vs. Ovenbird, and all three vs. thrushes
Common Yellowthroat vs. Kentucky Warbler
Swainson's vs. Worm-eating Warbler
Prothonotary vs. Blue-winged Warbler
Orchard Oriole (female) vs. female Summer Tanager
Rusty Blackbird from grackles, and all 3 from crows
Common vs. Boat-tailed Grackle
Blue Grosbeak vs. Indigo Bunting
Indigo Bunting (female) vs. sparrows, female House Finch, and female House Sparrow
House Sparrow (female) vs. sparrows, female House Finch, and female Indigo Bunting
Savannah vs. Song Sparrow
Field vs. Chipping Sparrow
Swamp vs. White-throated Sparrow
House vs. Purple Finch