Chapter 1: Hey! Wasn’t That a Robin?

Sometimes birds are misidentified because of tricky lighting effects that are ever present in Nature. It is always with a chuckle that I recall a bird that Robert P. Allen and I saw dash into a large bush on a New Jersey salt marsh only a few years ago. With our glasses we noticed that it had a green back and stripes on the throat. “A European species,” we whispered to each other, “or at least one from the Northwest.” It was a shy migrant and it did not feel safe on a salt marsh. After a full five minutes we finally saw it well. It was a robin.

Is there anyone in the United States or Canada who–barring illusions of the sort that fooled Hickey and Allen–does not recognize the American Robin at a glance? Even the most casual observer of birds knows the male robin to be about ten inches in stature, with a dark brown back, an even darker head, a yellow bill, perhaps some white on his tail and vent, and of course the trademarkish red breast. His mate is not much different, except that her head and back may be a little lighter, her breast and bill a bit duller.

Yet a traveler visiting all corners of the continent would soon discover that not all robins look exactly alike. Ornithologists have classified six or seven different populations of robins that vary among themselves in either size or shading or both. To be sure, the differences that separate these subspecies, or races, may appear rather trivial to the eyes of a layman; in fact, even the ornithologists themselves are not unanimous on the validity of distinguishing a few of the groups. (For example, it’s debatable whether robins living in parts of Mexico are a separate population from United States races.) And while the geographical ranges of the half-dozen recognized races tend to be mutually distinct, there is considerable overlap in several cases.

Robin Races

In any event, the most widely accepted populations of robins include:

1. Eastern Robins, who breed throughout eastern North America and, despite their name, as far northwest as Alaska. These birds, some ten inches in length, are the “typical” robins to which the other races are usually compared.
2. Southern Robins, who breed from Illinois and Maryland south to northern Mississippi, Alabama, and South Carolina. This race is smaller than the Eastern Robin, and their colors (for example, on the breast) are paler.
3. Black-Backed Robins breed in northeastern Quebec, Labrador, Newfoundland, and New Brunswick. This race is a bit larger than the Eastern Robin and also much darker throughout, with (as the name suggests) a blacker back.
4. Western Robins breed from British Columbia to Mexico and from the Pacific Ocean to the Great Plains. This race, slightly larger than the Eastern Robin, is similar in color except that the outer tail feathers lack white tips, the back is a bit lighter, and the breast somewhat paler.
5. Northwestern Robins breed from Alaska south through the Pacific Coast region of British Columbia into northwestern Washington. This race is about the same size as the Easter Robin (and thus is smaller than the Western Robin), but lacks the extended white on the tail feathers. In shading, the Northwestern Robin is much darker than the Western Robin and perhaps a little darker than the Eastern Robin.
6. San Lucas Robins are classified as a distinct species, and breed in Lower California around the Cape region. These beautiful robins are quite pale, with cream-colored breasts and gray instead of black on their heads.

It must be emphasized that none of these groups is really much different from any of the others. An occasional Western Robin may actually be as dark as the typical Northwestern Robin. Or the light-colored female of one race (for example, the Eastern) may closely resemble the male of another race (for example, the Southern). Or there may even be intermediate forms of robin occurring between two given populations.

Inasmuch as the breeding grounds of one subspecies may be the winter resort of a more northerly group, representatives of two different races may find themselves hunting side by side on the same lawn or football field during the hectic migration season. If so, then the two races inevitably intermix without restraint, totally ignoring the subtle differences between them in unhuman-like fashion. A robin is, after all, a robin, and no degree of mere racial distinction can ever change that reality.

Albinism and Melanism

A description of the robin’s plumage would not be complete without noting occasionally occurring exceptions to typical robin coloration. Albinism constitutes one of these exceptions. While never frequent, cases of albinism appear to be less rare among robins than among most other species of bird (albinos are also relatively common among English Sparrows, Redwinged Blackbirds, and Cliff Swallows). Among robins, albino individuals can be grouped into three categories that differ in the degree to which whiteness dominates the body’s coloration. Partial Albinos have several or many white feathers within their plumage, leading to a somewhat “streaky” appearance. Usually the head is normally pigmented, but white feathers are intermixed with normal feathers on the wings, tail, breast or back, or on any combination of these areas. More often than not the white streaks present an asymmetrical pattern. White Robins are extreme examples of partial albinism, since they are completely white all over. However, they differ from Total Albinos by having the robin’s typical dark brown eyes. A total albino has eyes which lack pigmentation and appear pink because of blood vessels in the eyes themselves.

This absence of eye shadow in total albinos, by the way, can make for a neat trick the next time such a robin walks up to you. Beam a bright light into one of the robin’s eyes while you look into the other. You’ll find that the eyeball you’re eyeing shines quite like a glowing furnace, as if the creature’s head were filled with coal instead of brain. This bird-beacon effect is possible because a robin’s eyes are nearly opposite each other and because only translucent cartilage separates the two oculi once light gets by the pigmentless peepers.

Albinistic robins almost surely have a shorter average life span than do normal robins, First and foremost, albinos are robbed of their protective coloration and in fact are made downright conspicuous before the ever-searching eyes of predators. Another factor working against an albino–or at least a total albino–is decreased visual ability, since the bird’s unpigmented eyes may have trouble functioning up to par in bright sunlight. Still a third disadvantage is the fact that albinos often possess a weaker constitution in general than normal birds, and thus they may not be as resistant to disease and harsh weather. Despite all of these problems, however, exceptional longevity is sometimes achieved by an albino robin. One male whose body was nearly all white was seen in Norristown, Pennsylvania, from 1939 to 1947, a span of nine years. Few normally colored redbreasts manage to live that long.

What effect, if any, white plumage has on a robin’s social life has yet to be satisfactorily determined. A few observers have reported isolated incidents of ostracism on the part of other robins toward the blanched individual. But on the whole, albinos—whether partial or total—appear to be accepted members of robin society. They are welcome at the flock’s communal feeding grounds and, if they live long enough, they are often able to secure a breeding partner. This latter fact may explain why albinism is not as rare among robins as among other birds; perhaps albinos in other species are not acceptable as mates and thus are denied the opportunity to pass on their albino trait to the next generation. Interestingly enough, it appears that female albino robins are more successful in finding mates than are male albino robins.

Another type of exceptional coloration is melanism, where the plumage is very dark or actually black. This abnormality is much rarer in robins than albinism, and melanistic specimens are highly valued by persons who obtain them. One black robin was owned by a saloon keeper near Jersey City, New Jersey, way back in 1880. This enterprising gentleman at first set a fancy price for his bird and, failing to find a purchaser, finally raffled off his sooty gem at $2.00 a chance.

In many cases, both melanism and albinism are undoubtedly rooted in genetics. Although albino mothers often rear babies who have perfectly normal plumage, the chances of begetting a pale-faced youngster are much greater with an albinistic parent than if both mom and pop are pigmented normally. Indeed, total albinism is probably entirely congenital in origin.

Partial albinism, on the other hand, is sometimes developed through the course of an individual’s lifetime. One robin, for example, possessed normal plumage when initially banded but was partially albino when recovered two years later. Numerous other cases of gradual change in color have been recorded, particularly among robins who at the time were living in captivity. Frequently these birds undergo a melanistic phase before entering an albinistic phase. Since melanism reflects an excessive increase in black pigment (which is called melanin), continuation of this condition may possibly exhaust the supply of, and hinder the ability to renew, melanin; if so, then albinism might be expected to ensue.

But exactly what physiological perturbation ultimately underlies such chameleonic changes is unclear. One ornithologist of the last century suggested that partial albinism was due to tapeworms in the intestine, since he had frequently discovered those creatures in albino robins as well as in albinistic individuals of other species. Conceivably these parasites could extract and monopolize some important color ingredient from the host’s diet. Although most of the reported caged robins appear to have received well-balanced meals, subtle dietary deficiencies may nevertheless have been an important factor. It’s been found, for example, that large mineral deficiencies often exist in the bones of abnormally colored robins. Also, captive flamingos who have paled usually get back in the pink after eating shrimp!

Other Physical Abnormalities

Rare plumage color is not the only manner in which robins can express their nonconformity. Sometimes abnormalities are hidden from casual human observation, as in the case of a dead female who, upon being dissected, was found to possess only one lung, the left lung being entirely missing. Other times the deformities are blatant, sacrilegious affronts to the robin’s normally good looks. In 1965 two different baby robins (one in New York, the other in West Virginia) were found with their respective tongues protruding down through their lower mandibles. In both instances the plight was probably the result of abnormal development rather than accidental injury. Misguided development also occasionally leads to eyeless babies who may survive well enough while under the solicitous care of their parents but who are otherwise doomed to a premature end.

Other deformities may not be fatal but merely nuisances or, perhaps even worse, embarrassments. One male robin completely lacked a tail and yet managed to return to his territory in the Boston Public Garden during three successive springs, thereby demonstrating that you don’t need a rudder to navigate the long robin migrations. Another bird, this one an adolescent hailing from Pennsylvania, grew two tails that were missing one and two feathers respectively (twelve is the normal number of tail feathers) but were, otherwise typical posteriors of the species.

As with tails, legs are a commodity in short supply for some robins and a bit too abundant for others. One-legged robins have frequently been reported, many no doubt the products of accidents though some may have been defective since birth. With a little practice these hop-a-long birds manage surprisingly well, although landing on a perch may present ever-recurring difficulties. Perhaps the strangest robin of all, however, was a youngster who had three normal legs. Two of these limbs were on the left side, one above the other, while the third was in its regular position on the right.

Before we leave the physical characteristics of the American Robin, idle interest inspires mention of a few other facts. Adults usually weigh from seventy to eighty grams (about six birds to the pound), although their weights change a bit before and after migration and, in females, during the reproductive season. Nearly 15 percent of this weight is contributed by the robin’s fight muscles, and only 4 percent by the bird’s hollow skeleton. When robins rest, their hearts pump some three hundred fifty times per minute, and their lungs suck and spout air about forty-five times per minute. The robin’s body holds a temperature of around 109.79°F (although this varies with activity and time of day) and is covered by approximately twenty-nine hundred feathers (compared to twenty-five thousand for swans and zero for most humans).

How the American Robin Was Named

With these important facts behind us, let’s see why we call that redbreasted worm-hunter who patrols your front lawn a Robin. In Normandy of long, long ago, people used to refer to a love-struck adolescent as “Robert” (a name that means “gleaming fame”), and this word was eventually abbreviated to “Robin.” The Normans brought the term to the British Isles when they invaded in 1066 A.D., and the name was given to a small bird who previously had been called “ruddock” because of his red breast. This little bird, who like a fiery youth in love vigorously defended his nesting territory against all challengers, was called “robynet redbreast” (meaning “little Robin Redbreast”), or later, simply “Robin.” This English or European Robin looks much like our Eastern Bluebird in both size and color, and is the bird appearing so often in British literature (for example, a male robin played the role of hero in the melancholy tale of “Babes in the Wood,” in which he blanketed the chilled title characters with leaves).

When English colonists came to this country and failed to find their beloved redbreast here, they gave that bird’s name to our much larger robin who—while bearing a similar ruddy breast, robust spirit, and friendly disposition—is actually not closely related to the English bird at all. Comparable nostalgic christenings by homesick Britons have befallen birds in many parts of the world, birds frequently having little in common with the European Robin except a reddish breast.

Interestingly, American Robins have a few namesakes of their own. One is the Beach Robin, a redbreasted sandpiper who winters along the eastern coast of the United States. Another is the Sea-Robin, a homely flat-nosed fish who sort of resembles a bird because of its large winglike pectoral fins, and who vaguely resembles a Robin because of its generally reddish color. Sea-Robins are common along the eastern coast as far north as Cape Cod.

We might also mention that our redbreast has other names besides American Robin. A common one is “Fieldfare,” which is another hand-me-down label from a British bird, this one a migratory thrush of the same name. French Canadians used to refer to our robin as “Merle,” and the Pennsylvania Dutch called the species “Omshel.” Native Americans of course had their own names for the robin: the Dog-rib Indians near Great Slave Lake in northwestern Canada called robins “Goshi,” while the northeastern Penobscots referred to redbreasts as “Cha La Cha Lee.”

In addition to having these common or popular labels, the Robin travels in the world of biologists under a latinized alias which constitutes the bird’s scientific name. Every known living creature, both plant and animal, has been classified by taxonomists along a hierarchy of increasingly specific groupings. This classification system, developed by the great Swedish botanist Karl Linnaeus during the eighteenth century, assigns for each plant and animal its own little identification tag so that scientists won’t lose it within the enormous variety of Nature. The robin’s tag reads as follows:

KINGDOM: Animalia (as opposed to plants)

PHYLUM: Chordata (animals with a notochord or backbone)

CLASS: Aves (chordates who are birds)

ORDER: Passeriformes (perching birds, as opposed to, say, Penguins)

FAMILY: Turdidae (perching birds who are thrushes)

GENUS: Turdus (one of five different thrush genera)

SPECIES: migratorius (all American Robins except the San Lucas Robin, whose species is confinis)

For most purposes it suffices to identify an animal only in terms of genus and species. Thus the robin is known in scientific circles as simply Turdus migratorius, which in Latin means “wandering thrush” (a perfectly appropriate name as we shall later see). If one wants to further specify a particular race of robins, an additional term must be cited: Turdus migratorius migratorius (Eastern Robin), Turdus migratorius achrusterus (Southern Robin), Turdus migratorius nigrideus (Black-Backed Robin), Turdus migratorius propinquus (Western Robin), Turdus migratorius caurinus (Northwestern Robin), and Turdus migratorius permixtus or phillipsi for two questionable Mexican races of American Robin.

It is important to realize that the particular groups to which an animal belongs are not chosen by scientists arbitrarily but instead represent an attempt to delineate the evolutionary relationships that a given species bears to other living things. For example, by knowing that the European Blackbird’s Latin name is Turdus merula, one can deduce that scientists believe this bird to be more closely related to our robin (since both birds are grouped within the same genus—Turdus) than either bird is related to the Common Crow (Corvus brachyrhynchos) or to the European Robin (Erithacus rubecula). To a large extent, this relationship is reflected in physical similarities between the two species. As true thrushes, both the American Robin and European Blackbird lay bluish-green eggs, have slender bills, and sport speckled breasts (in the young of the robin, in the female of the blackbird).

But in addition to physical resemblances, evolutionary relationships are also reflected within the dimension of behavior. Indeed, the American Robin and European Blackbird probably resemble each other more in terms of their behavior than they do physically—they both use mud in building their nests, they both rear more than one brood each season, their songs are rather similar, and they practice similar lawn-running habits.

Fortunately, the early English colonists failed to notice this close behavioral similarity of our robin to their blackbird and instead saw only the superficial similarity of breast color with their own tiny European Robin. Otherwise we might all be singing, “When the red, red blackbird goes bob-bob-bobbin’ along.” And that just doesn’t rhyme.