Bald Eagle: The Bird Behind the Symbol

(c) Jack Ballard

Best known in our nation as a symbol of the United States, likenesses of the bald eagle appear on most official seals and have also appeared on the backs of many coins. The bald eagle is our national bird. However, it’s a species whose name doesn’t seem to fit the creature. After all, the head of an adult bald eagle is clad in feathers, not devoid of covering as the term “bald” implies.

However, when these eagles were first named, the word “bald” was commonly understood as a shorter version of “piebald” which referred to someone with a white head of hair rather than a head lacking hair. Thus, the bald eagle’s name perfectly fits it appearance when considered against the vocabulary of early America. For the pioneers who encountered them, bald eagles were considered “white-headed eagles,” based on the meaning of their name.

Although their striking hoary heads and matching tail feathers are the trademark features of these magnificent birds, not all bald eagles exhibit them. Young eagles do not attain this pale plumage on the head and tail until they reach reproductive maturity, usually at four or five years of age. Prior to this time, their appearance exhibits varying stages of development. For the first year or two, bald eagles are brown, showing little or no white on their heads and tail feathers and are easily confused with young golden eagles. Junior members of both species exhibit white mottling on their bodies and  undersides of their wings. Around three years of age, bald eagles begin to acquire their trademark white head and tail, although brown streaking is common on both.

Distinguishing immature bald eagles from all golden eagles is a challenge, but attention to a few unique markings will do the trick if you have time to study a bird through binoculars or at close range. Golden eagles have feathers on their legs extending all the way to their toes while the large, yellow legs of the bald eagle do not have feathers on the lower parts. Bald eagles also exhibit a blockier head and slightly shorter tail than golden eagles. In most habitats in the contiguous United States, golden eagles are also noticeably larger than their bald cousins.

Although immature birds can be very difficult to distinguish in the field, bald and golden eagles are unrelated, save for their name. In fact, the term “eagle” is somewhat confusing in itself. For eagles are no more than oversized raptors that could well be called “hawks.” Several species of “eagles” in Europe are smaller than the red-tailed hawks of North America. Taxonomically, bald eagles are aligned with the broader family of sea-eagles (haliaeetus) which include the white-tailed eagle of Greenland and Eurasia, and the mighty Stellar’s sea-eagle of northeastern Asia, a species occasionally see on Alaska’s Aleutian Islands. Golden eagles are part of the family of “true eagles” (aquila), distinguished by fully-feathered legs. The wedge-tailed eagle of Australia shares this family with the golden eagle, similar in size and color, but with noticeably longer necks and legs.

The differing families of the bald and golden eagles also originates in their feeding habits. Bald eagles are seldom found far from water, and are enthusiastic consumers of fish, whether taken on their own or usurped from ospreys. They’re also very prone to dine upon carrion, especially in the winter months when road-killed deer and other creatures are available. The diet of golden eagles, by contrast, consists of land animals. Rabbits, hares, ground squirrels and snakes comprise the bulk of their diet, although they’re capable of taking much larger when necessary. However, bald eagles are also capable of taking land animals for prey, and will do so in areas where fish are less available as a foundation for their nourishment.

Although slightly smaller than golden eagles, bald eagles are nonetheless large and imposing birds. Their size varies considerably depending on where they live. Males found in Florida, for example, are much smaller than those soaring the skies of Alaska. Florida males weigh slightly more than five pounds and achieve wingspans of around six feet. Large males in Alaska, by contrast, may weigh 13 pounds with wings spreading to nearly seven feet. No matter where they live, bald eagles are an example of sexual dimorphism, a term used to describe species where males and females differ in relation to some important trait. In bald eagles the variation is related to size. Female bald eagles are typically about 25% larger than the males. 

The impressive size of bald eagles corresponds to equally notable nests. These white-headed raptors construct the largest nests of any bird in North America, structures sometimes so bulky it scarcely seems a tree could hold them without collapsing. However, bald eagles tend to choose very large trees for their nests, an important habit considering their nurseries of branches and twigs often weigh a ton and may be over 12 feet high and eight feet wide. A pair of eagles usually returns to the same nest site year after year, adding additional material each spring. Considering bald eagles live about 20 years in the wild it’s no wonder their nests, with each yearly “addition,” attain such impressive sizes.

Currently, bald eagles nest can be found over most of the contiguous United States and Alaska, although their range was once much, much smaller, especially in the lower 48 states. Eagle numbers declined dramatically in the 19th and early 20th centuries due to habitat destruction and hunting. Protections enacted in 1940 as the Bald Eagle Protection Act helped the birds somewhat, but the 1950s brought another, exceedingly serious threat to these birds whose population had plummeted from an estimated 400,000 individuals in the 1700s to just over 400 breeding pairs. Like many other raptors, bald eagle numbers declined precipitously in the decades following the widespread application of DDT and other pesticides for agricultural use in the 1950s. DDT absorbed by eagles through their prey disrupted their metabolism of calcium, causing females to lay eggs with paper-thin, easily-broken shells. Pesticides also led to infertility among the birds, severely curtailing their reproduction. Bald eagles became the “poster bird” for the DDT ban in the United States in the 1970s, although their potential for extinction in absence of the ban was potentially as acute for ospreys, another fish-loving raptor.

Since their designation as an Endangered Species in 1967, the recovery of bald eagles in the contiguous United States is one of the most thrilling conservation stories of our time. Once DDT was banned, eagle numbers began to increase and their range expanded. Tens of thousands of bald eagles now glide above the seacoasts of the Atlantic and Pacific Oceans, and thousands of large lakes and rivers in between. In 2007, bald eagles were completely removed from Endangered Species protections and are now considered a species of “least concern” by the International Union for Conservation of Nature (IUCN), meaning their health and population currently face no significant obstacles.

Breathtaking in flight, beautiful to the eye, the bald eagle is not only the symbol of our nation on official documents and governmental paraphernalia. The majestic birds also symbolize the power and will of the America people to protect wildlife in jeopardy, a national trait still needed in relation to other species both now and in the future.

A Tailless Whitetail

(c) Jack Ballard

Near the edge of town during mid-summer, just at twilight, I spied two whitetail bucks feeding in a meadow. Intrigued by their large, fuzzy antlers, I pulled over at the side of the road to give my son in the back seat a better look. On closer examination, we noticed something very strange about one of the deer. He had no tail.

A few months later, while puttering about trying take photos of a jackrabbit, I noticed a buck deer bounding pell-mell in my direction. It was a sight I’ve seen a thousand times, but something didn’t seem right. Viewing the photos on my computer later in the day, I recognized the tailless whitetail. It was the same buck, absent the trademark white flag normally carried upright on the rump of a deer when running.

Initially amused, I soon found myself zooming in on the image of the unfortunate creature to examine its missing appendage. Within the tail of a whitetail deer is a series of thin bones, much smaller but similar to those in the spine. This buck wasn’t simply missing the hair on its tail. Its tail was completely gone, severed from its body precisely at the base as if it had been surgically removed by a mentally unstable veterinarian.

And so I pose some obvious questions. Has anyone else seen a deer without a tail? Does anyone know how a whitetail might lose its tail? Maybe all those kids trying to pin the tail on the poor donkey could help out this buck. But perhaps not. I think they’d have a hard time catching him.

The Buzz on Bees

(c) Jack Ballard

In our culture, people hold two primary associations with bees: stings and honey. In fact, neither are so closely related to bees as most people imagine. While nearly every species of bee is capable of delivering a sting, under normal circumstances bees are highly docile. Only when squeezed or directly harmed will the average bee thrust its stinger into the hide of a human. Threaten the hive, and a whole swarm of bees may sting you. Other than those two instances, bees would much rather go about their business than prick people. Many stings attributed to bees actually come from wasps which are much more aggressive and far more likely to sting with minimal provocation.

Honey comes from bees. However, most people fail to realize that very few species actually produce it. The European honey bee has been widely domesticated and accounts for most of our nation’s honey production. Of all the other species of bees inhabiting the world, just a handful of them make honey.

How many kinds of bee are there? The number and variety are astounding. Some 20,000 different species of bees buzz the planet, existing on every continent except for Antarctica. From coastal lowlands to barren mountaintops, bees make their home in every type of habitat that nurtures plants requiring insects for pollination. In size, bees range from tiny workers of the trigona minima species who barely exceed 1/16 of an inch to females of the megachile pluto species who can reach lengths slightly exceeding 1.5 inches. Bees range in color from muted blacks and grays, to red, yellow, orange and metallic hues of green and blue. Not all bees rely on pollen and nectar for sustenance. Some glean floral oils from plants. Vulture bees, a species of stingless bees, feed on dead animals.

Diverse in size and feeding habits, bees also exhibit a wide range of social structures. Most people have some elementary understanding of the complex relationships of bees in a honey-producing hive. A hive of honey bees may contain up to 40,000 bees, with the queen producing 1,000 to 2,000 eggs per day to replace worker bees lost to predators while foraging and those dying of old age. However, there are many forms of bees that exist in colonies containing a few dozen to a few hundred individuals. Bumblebee colonies typically contain around 50 to 200 bees in August or early September when their population is at its highest. Still other species of bees are loners, not forming colonies at all. The females of these types of bees, known as solitary bees, make nests in holes in the ground, decaying wood or the hollows of reeds. They often specialize in collecting the pollen of a particular plant or a single type of plant, such as sunflowers. Some species of bees are parasitic, laying their eggs in the colonies of others or even killing the resident queen and forcing the workers of the deposed matriarch to rear their young.

Whether solitary or living in a colony with thousands of members, bees perform a critical role in maintaining life on earth for a bewildering array of plants and the creatures (including humans) who consume them. Bees are the most important pollinator of flowering plants on the earth. When foraging for pollen or nectar, bees transfer pollen from flower to flower, facilitating reproduction. Scientists estimate that over 30% of the food consumed by humans is garnered from plants requiring insects for pollination, most of which is accomplished by bees.

However, worldwide populations of bees are declining dramatically. In the 35 year period from 1970 to 2005, most of the wild honey bee colonies in the United States were wiped out due to pesticides, urbanization, parasites and disease. Very few wild honey bee colonies now exist in our country. In 2006 and 2007, a dramatic drop in bee numbers, both domestic and untamed, sparked a great deal of alarm among biologists in the United States. Labeled “colony collapse disorder,” this unprecedented decline in bee numbers caused a great deal of warranted concern among crop and vegetable growers, regarding the ability of their crops to be effectively pollinated without bees. Some researchers now believe a fatal combination of a fungus and a virus was responsible for this colossal collapse in the bee population. Bee numbers continue to decline. Pesticides applied for the control of other harmful insects often exterminate bees as well, including bumblebees and other solitary species that play an important role in pollinating many flowering plants. Increasingly, domestic honey bee colonies are moved about the country, not so much for their own good, but for the pollination of crops and flowers.

Of the solitary bees, many species are stingless or only willing to sting in extreme cases of self-defense. Communal bees, such as honey bees, are also reluctant to sting, but may become quite aggressive when defending their hive. When they sting, these bees release a pheromone, a chemical substance detected by others bees which causes them to join the attack on the aggressor, either stinging it to death or driving it from the hive.

Stinging a human is generally fatal to the bee. Bees’ stingers are more suited for battle with other bees than humans or other skinned mammals. When a bee stings a human, barbs on the stinger cause it to become so firmly embedded in the skin that the bee cannot pull it free. Instead, a sizeable chunk of the bee’s hide is left behind with the stinger when it retreats after imparting the sting, a wound which is almost inevitably fatal.

Thus, the idea that bees can sting only once applies quite accurately to their painful interactions with humans and other mammals, but isn’t true of aggressive interactions between bees or between bees and other insects.

One of the bulkiest bees in America is the bumblebee. An important pollinator, bumblebees are often seen buzzing around suburban vegetable and flower gardens. Their flight has been characterized in song, and also described as defying the laws of flight. While bumblebees’ aerial antics are certainly worthy of a melody, the supposed theoretical prohibitions on their flight are in error. The idea that bumblebees are theoretically incapable of flight probably stems from a book by French scientists published in the 1930s where the authors applied principles of fixed-wing flight to the bees. More recent analysis shows that bumblebees use exceedingly fast, irregular and rotational wing movements which generate sufficient lift and propulsion for their buzzing, erratic patterns of flight.

Often misunderstood, bees are an integral strand in the complex web of biological interactions that maintain life on earth. Encountering a bee in the garden or camp isn’t a cause for alarm, but an opportunity to consider their critical connection to human life and our need to maintain a planet hospitable to our buzzing benefactors.