Not directly part of the bill, the chin is the area of feathers immediately adjacent to the base of a bird’s mandible. The chin is often hard to see and often blurs into the throat, bib or chest. Waterbirds are particularly easy to identify the chin feathers since their bills protrude more markedly. In some species, the color of the chin may vary from the throat or face, providing a valuable identification clue.
Caruncle
Caruncle: King Vulture (top-left) Muscovy Duck (top-right) Wattled Crane (bottom-left) Male Gould’s Wild Turkey (bottom-right)
A caruncle is defined as ‘a small, fleshy excrescence that is a normal part of an animal’s anatomy’. Within this definition, caruncles in birds include wattles (or dewlaps), combs, snoods, and earlobes. Probably the most spectacular caruncle would be the King Vulture. The head and neck are devoid of feathers, the skin shades of red and purple on the head, vivid orange on the neck and yellow on the throat. On the head, the skin is wrinkled and folded, and there is a highly noticeable irregular golden crest attached on the cere above its orange and black bill, this caruncle does not fully form until the bird’s fourth year. Both the african Wattled Crane and the wild Male Gould’s Wild Turkey are a close second.
Frontal Shield
Frontal Shield: Common Gallinule (top-left) American Coot (top-right) Wattled Jacana (bottom-left) Purple Gallinule (bottom-right)
In some bird species, the bill extends in a frontal shield onto the forehead. The frontal shield, also known as a facial shield or frontal plate, is a feature of the anatomy of several bird species. Located just above the upper mandible, and protruding along the forehead, it is composed of two main parts: a hard, proteinaceous callus and a soft, fleshy corium. It is thought to play roles in protection, mate identification, sexual selection, and territorial defense.
Hooked Bills
Hooked Bill: Black Vulture (top-left) American Kestrel (top-right) Barred Owl (bottom-left) Female Slaty Flowerpiercer (bottom-right)
Birds of prey and birds that scavenge carrion, including eagles, hawks, falcons, ospreys, owls, vultures and buzzards, have hooked beaks. The upper portion of the beak curves down over the lower portion and comes to a sharp point. These beaks are designed for fatally biting prey and tearing flesh. One lovely exception are the Flowerpiercers, birds who steal nectar by piercing the base of flowers.
Waterfowl Bills and Nails
Duck Bills and Nails: Male and Female Mallard (top-left) Male Ruddy Duck (top-right) Female Greater Scaup (bottom-left) Canadian Goose (bottom-right)
Dabbling ducks like mallards, pintails, and gadwalls have round-tipped bills that are relatively flat, about as long as the duck’s head, and deeper than they are broad at the base. The edges of the bill are soft because waterfowl often find food by touch, feeling their food much as we sense things with the tip of our finger. Many waterfowl bills have a nail at the end that is used for hooking or moving food items as we might use our fingernails to manipulate something.
Mallard Duckling (Anas platyrhynchos)
After their incubation, ducklings must break out of the egg. To do this, ducklings are equipped with an egg tooth, a sharp appendage on the bill that falls off once they are free of the egg. Hatching typically takes three to 24 hours. While this photograph does not show an actual egg tooth, the nail is pink and it was too good not to include.
Billing
Billing between Bare-Throated Tiger Heron (Tigrisoma mexicanum)
During courtship, mated pairs of many bird species touch or clasp each other’s bills. Termed billing (also nebbing in British English), this behavior appears to strengthen pair bonding. The amount of contact involved varies among species. Some gently touch only a part of their partner’s beak while others clash their beaks vigorously together.
Nape
Nape: White Faced Whistling Duck (top-left) Marigold Lorikeet (top-right) Kererū (bottom-left) African Jacana (bottom-right)
The nape is the back of a bird’s neck. The color of the nape will often match either the bird’s crown or back, and that color may extend onto the sides of the neck to varying degrees depending on the species. Many songbirds and raptors have very short necks and the nape is a relatively small area, while waterfowl and wading birds typically have longer necks with a more distinct nape that may also be called a hindneck. Similarly, the color of the nape can continue into the crown or even around the neck into the chin and throat.
Wings
Flight Feathers of a Parrott
Wings are complicated and have functions which are probably incompletely understood. Primary feathers located on the outside edges of the wings, these are the feathers that are narrowest and longest. Wing coverts are the feathers that are located on the leading edge of the wings. They cover the bases of the primary and secondary feathers. The alula is a small projection on the anterior edge of the wing of modern birds and a few non-avian dinosaurs. The word is Latin and means “winglet”; it is the diminutive of ala, meaning “wing”. The alula is the freely moving first digit, a bird’s “thumb”, and typically bears three to five small flight feathers, with the exact number depending on the species. In most situations, the alula is held flush against the wing; however, it can be manipulated. When flying at slow speeds or landing, the bird moves its alula slightly upwards and forward, which creates a small slot on the wing’s leading edge. This functions in the same way as the slats on the wing of an aircraft, allowing the wing to achieve a higher than normal angle of attack – and thus lift – without resulting in a stall.
Wingbars
Pine Siskin (Spinus pinus). Sierra Vista, Arizona
A wing bar is a distinct field mark on the top of a bird’s wing caused by contrasting colors on the tips of the primary and secondary coverts. Whether the wing is folded at rest or extended in flight, these contrasting tips form a distinct stripe of color across the wing that can be useful for identifying bird species. When the wing is spread, the bar will show as a stripe down the center, stretching along the length of the wing roughly from the bird’s body to the wingtip, though not all wing bars stretch the entire wingspan.
Wing Patch
Wing Spots: Male White-Winged Tanager (top-left) Male Red-winged Blackbird (top-right) Male White-Lined Tanager (bottom-left) Verdin (bottom-right)
Wing patches or spots of color on the wing can be valuable field marks in birds. These little patches of color remind me of WWII fighting aces that received honors for their heroics.
Upper and Underparts
Brown-Hooded Parrot (Pyrilia haematotis). Laguna del Lagarto Lodge, Costa Rica
Spanning from wing to wing, underparts denote a bird’s underside. The “armpit” of a bird, often host covert feathers called axillaries. Other names include, axillary feathers and lower humeral coverts. A bird’s wingpit is the equivalent to the human armpit, the area close to the body on the interior of the underside of the wing. This area can show distinct colors or markings vital for bird identification like the red feathers in the axillaries of the Brown-Hooded Parrot. Look for streaks, barring, or color patches on any in-flight bird you’re trying to identify. Often, I include photography of the wings spread which are not nearly as good as a sitting bird but notice how different the colors are when the wings are spread. The names are the same, primaries, secondaries and coverts but note how the color of the underside of the wings is quite different than the top.
Breast
Breast: American Robin (top-left) Adolescent American Robin (top-right) Black Phoebe (bottom-left) Black-Billed Magpie (bottom-right)
The chest (also called the breast) is the upright part of the bird’s body between the throat and the abdomen or stomach. A bird’s chest may be differently colored or marked with stripes, streaks or spots that can help with identification. The Robin has an orange chest from the neck down to the white abdomen or stomach which is replaced by by spots in the adolescent. Where are the breast stops and the abdomen begins is the subject of some discussion. The Black Phoebe or the Black-Billed Magpie pictured here both would be considered to have dark breasts or chests with white abdomens.
Bib
Bib: Egyptian Plover (top-left) Male Gambel’s Quail (top-right) California Scrub Jay (bottom-left) Female Northern Flicker (bottom-right)
Defining a bib on a bird can be a bit tricky since the reference is to an item of clothing rather than anatomy. I personally have a fondness for bibs with borders, regardless of their size. A small bib might cover the neck, larger it might cover the breast. Or in the case of the Northern Flicker, it might be an apostrophe at the top of the breast.
Gorget
Gorget: Male Fiery-Throated Hummingbird (top-left) Male Volcano Hummingbird (top-right) Male Tufted Coquette (bottom-left) Male Allen’s Hummingbird (bottom-right)
Gorgets (from the French gorge meaning throat) started off in the Middle Ages as a woman’s fashion piece, usually linen, that wrapped around their neck or was part of a hood. lt eventually became a leather or steel collar worn by men to serve as protection for the throat, eventually growing into a full piece of armor itself that would cover the upper portion of the chest as well as the throat. The bird field making gorget is used almost exclusively for hummingbirds, those lovely sparkling necklaces that glow at just the right angle.
Resplendent Quetzal (Pharomachrus mocinno). Paraiso Quetzal Lodge, Costa Rica
Even though the Resplendent Quetzal is not a hummingbird and some might call the green an upper chest, I think it possesses all the royalty and glamor to be called a gorget.
Crissum and Cloaca
The cloaca is the single posterior opening for a bird’s digestive, urinary, and reproductive tracts and is used to expel feces and lay eggs. The cloaca is found on the rear of the body under the base of the tail, covered by feathers on the extreme lower abdomen. Those feathers surrounding the cloaca are called the crissum or undertail coverts. The cloaca and the area of the body where it is located, as well as the physical slit opening itself, is also frequently called the vent. During mating, the male perches on top of the female, who moves her tail feathers to the side to expose her cloaca. Arching back, the male rubs his cloaca against hers. During the breeding season, the cloacal area swells and the tissues protrude slightly outside the body to make breeding easier. Male birds show more swelling, and bird banders will gently blow on a bird’s vent to expose the cloaca and examine its size to determine a bird’s gender.
Rump Spot
Chestnut-Mandibled Toucan or Swainson’s Toucan (Ramphastos ambiguus swainsonii). Laguna del Lagarto lodge, Costa Rica
As I said above, the under tail coverts or cloaca are beneath the tail. In the Chestnut-Mandibled Toucan we see white rump feathers above the tail and red under tail coverts or cloaca.
Passarine Feet
A Passerine Male Purple Honeycreeper (Cyanerpes caeruleus). Asa Wright Nature Center, Trinidad
Sometimes known as perching birds or songbirds, passerines are distinguished from other orders of birds by the arrangement of their toes (three pointing forward and one back), which facilitates perching. The foot of a passerine has three toes directed forward and one toe directed backward, called anisodactyl arrangement, and the hind toe (hallux) joins the leg at approximately the same level as the front toes. This arrangement enables passerine birds to easily perch upright on branches. Even though about half of all birds are passerine the evolutionary history of the passerine families and the relationships among them remained rather mysterious until the late 20th century. In many cases, passerine families were grouped together on the basis of morphological similarities that, it is now believed, are the result of convergent evolution, not a close genetic relationship. For example, the wrens of the Americas and Eurasia; those of Australia; and those of New Zealand look superficially similar and behave in similar ways, and yet belong to three far-flung branches of the passerine family tree; they are as unrelated as it is possible to be while remaining Passeriformes.
