The Cormorant: The Devil Undisguised?
by Dr. Tom Kazo, Ph.D. and Donna McVicar Kazo

Many sports fishermen no longer attach the words "predator" or "magnificent fishing machine" to daydreams of fishing and fine boats. Now they may attach those descriptive phrases to Nature's own feathered fishing machine, a bird called the cormorant. The feelings that come with that attachment are not those of admiration for its natural abilities, however, but of suspicious curiosity and occasional outrage. The double-breasted cormorant (Phalacrocorax auritus), one of seven species found in the waters of North America, has carried a macabre reputation of devilish gluttony since its first encounters with ancient man.

Photo of a cormorant, by David Lamfrom

When nature becomes unbalanced for any reason, a chain of events begins, subtly at first, but eventually with long-term effects on not only flora and fauna, but on the entire ecosystem in which they exist. Too many times Man has allowed greed, rumor, superstition and lack of understanding to lead him into the eradication of a species while furthering his personal goals. Once attained, the results can be a drastic misalignment of Nature that can also upset the goals of other men.

Before one can intelligently confront a problem in Nature, extensive knowledge must be gained on the subject. Into this, enters the cormorant. The cormorant is a fish-eating bird, and unlike others in its classification does not prey on other animals. It eats fish and only fish. Since Biblical times, this bird has been an enigma, labelled with names such as devil bird, sea crow, even shark, reflecting the historic animosity of the fishermen who have been forced to compete with them.

Many people know only of the cormorant as the bird leashed by ancient Oriental fishermen, forced to release its catch to its owner. A decade ago, the average North American fisherman seldom saw a cormorant; of late, this three-foot-tall, scraggly-winged black bird has prompted discussions, extensive research, curses and downright venomous threats, depending upon the mindset of the person involved.

My profession, ethology —the study of animal behavior and its interactions with the environment— and my lifelong love for fishing have constantly and enjoyably crossed paths. It was my personal curiosity as an avid fisherman that led on my professional curiosity as an ethologist to determine if the fast-spreading rumors of cormorants depleting favorite "fishing holes" were valid. I have studied cormorants singularly and in great numbers, on coastal estuaries and wetlands, traveling deep into the inland lakes, streams, ponds and reservoirs of North America. I have seen how their activities, now bold and brazen, have replaced their natural fear and shyness of Man. Anyone who seeks pleasure or livelihood by coming into contact with fish may have valid complaints against the gluttonous behavior of the cormorant. Hatcheries, fisheries, fish farms, bait fishermen, sports anglers, charter boat crews and others all over North America have volubly expressed their concerns.

How is it that a bird of such unassuming appearance has acquired this reputation? A glassy blue eye, hooked beak, orange-colored throat pouch, connected to a long "S" shaped neck, placed upon a lean, crow-like, six-pound body, all awkwardly balanced upon clumsy webbed feet, result in a comic character. When observed drying his feathers in typical spread-wing posture, straining to keep balanced upon his chosen perch, he most strongly resembles a windblown umbrella.

Photo of a cormorant, by David Lamfrom

After plunging into the water like an out-of-control aircraft, however, his performance is nothing less than exquisite. Every clumsy move made out of the water is transformed into the power and finesse of a guided missile in the depths. Observational research has concluded that this wily character has the ability to close off his nostrils and breathe out of the corner of his mouth. His feather structure greatly decreases buoyancy, allowing complete entry into the water. The plumage retains water, and the outer portion of the feathers is wettable. A layer of air is maintained next to the skin. Add to this is a skeletal structure heavier than most, with bones that are solid, not hollow, and eyes that are adapted for both aerial and underwater vision and the result is a breathing projectile capable of diving to 80 feet and maneuvering for at least a minute at speeds to 38 miles per hour. Beneath the waves in a trail of tiny bubbles, the long, gangly neck of this underwater flyer can easily overtake the speediest of fish, grasping it in its midsection.

After a quick swim to the surface, only the cormorant's snakelike neck pops out of the water. Unable to float, his body three fourths submerged, he's reminiscent of a waterlogged submarine with a bent periscope. Then, with a well-practiced, dexterous technique, the fish is flipped into the air so that it is positioned with fins back for a final plummet down the bird's gullet. An honest half-hour of fishing will likely yield his daily catch, which has been documented by autopsies revealing as many as eight fish totaling up to two pounds, some of them 16 inches long.

To exit the water, the heavily waterlogged bird must flap wildly and struggle to the first available perch. Then the spread-wing drying posture takes place, which is not for thermal regulation, as once thought, as the layer of air next to the skin is an excellent insulator. Once dry, the cormorant moves on after a characteristically sloppy half-running, half-stumbling takeoff. Adaptation for diving has left the cormorant less agile in the air. Unlike its cousin, the pelican, it is unable to glide or soar, but must rapidly pump its wings to stay airborne.

The gluttonous behavior patterns of the cormorant, combined with its devilish appearance and almost supernatural fishing abilities, have for centuries caused superstitious fears and enmity in the hearts of fishermen. Biologists, officers and personnel of wildlife management systems, state parks and fisheries across the nation have told me they frequently hear, "Why are there so many cormorants? What can be done about their growing numbers?" and the question closest to an angler's heart, "Are they eating all the fish?" —seemingly simple questions with far-reaching, entangled and incomplete answers.

Prior to 1972, a North American angler at his favorite fishing site would only on occasion see a cormorant. Today, it is not uncommon to observe them in the thousands depending upon the geographical location and time of year. The banning of DDT in 1972 was a milestone in the remarkable recovery of the cormorant. The use of this pesticide had been found to be a major factor in the decline in wildlife populations at many levels on the food chain. Studies made of fish-eating birds found their eggs to be sterile or so brittle that they shattered beneath the weight of the parent birds. Deformities were common. Not only the cormorant, but his predators, such as the bald eagle, were affected.

Another major pollutant of the waterways, found in lubricants and industrial wastes, was polychlorinated biphenyls, or PCB's. Banning PCB's in 1976 was another essential step towards cleaner, healthier waterways, the fish in them, and the creatures who ingest those fish. Ornithological and lexicological studies done by private, public and governmental agencies are finding that the long-term effects of pollutants in our waterways are still being revealed. They point out that the cormorant's recovery may only be short-term, as once again reproductive defects and deformities are on the rise. Research found that the cormorant's ability to hold 250 million times the toxic residues found in the water makes the bird an effective "PCB alarm" to governmental agencies.

The rapid breeding rate of the cormorant is one factor as to why it is one of the most-researched waterfowl today. The embryos in eggs are far more easily studied than those buried deep within the uterus of a mammal, and the results of those studies are extrapolated upon creatures with a slower rate of reproduction.

When asked, "What use are cormorants to humans?" Jim Ludwig, past president of the Michigan Audubon Society, states that one tentative answer is that the research on the booming cormorant population "may prevent human suffering, particularly among people who eat fish, and spare us from human stupidity." Like the "canary in a coal mine," things happening to the cormorant now are indicators of what will happen to other wildlife and to people.

Photo of a flock of cormorants, by Dr. Tom Kazo

Another factor in the comeback of the cormorant is its remarkable ability to adjust its behavior in order to adapt to new situations. Once the cormorant traditionally migrated to Mexico and Central America, where baitfish were plentiful and people weren't. This southerly route normally crossed over America's wetlands, where the flocks would briefly stop and feed. Many of these have now been destroyed, replaced by a man-made labyrinth of reservoirs, canals, lakes and ponds, all richly laden with fish. Comfortably warm, with plenty of perching sites and natural nesting areas, the southern United States became a Utopia for cormorants.

This outstanding ability to adapt its behavior extends to the diet of the cormorant. I have observed in my studies that these birds will rapidly modify their eating habits according to their need, changing behavior patterns several times in one month. Diets also reflect the geographical location. The traditional food of cormorants was baitfish or "trash fish," various species that preyed, incidentally, upon the fry of gamefish. Research indicates that by preying greedily upon their normal types of fish, the cormorant allowed trout, salmon, bass and like gamefish to stand a better chance for survival.

A major diet change was the southern catfish, bred on newly established farms by the hundreds of thousands in open shallow man-made ponds, prime for feasting. The catfish farmers of the South expressed their resulting consternation and ire with a strong desire to depredate the entire cormorant population. They learned that the cormorant is protected by the Migratory Bird Act of 1972.

Many millions of dollars were subsequently spent in methods of determent, ranging from 25,000-decibel noise machines, to butane cannons, to rubber mannequins wildly leaping from steel drums. Even radio controlled model aircraft were used to engage in aerial combat with the cormorants. More birds than planes survived these dogfights, making this effort one only for the enthusiast.

Although depredation permits are obtainable, abuse has made the process a nightmare of red tape. One farmer, having been given permission to shoot 50 cormorants per year, was discovered to have destroyed over 15,000 birds of all types. Thwarting some very imaginative and expensive devices is a particular talent of the cormorant. Outsmarting this bird seems to be a one-shot deal, and if you miss, he may not allow you a second chance, concurs Curt Kraemer, a fish biologist with the State of Washington Department of Wildlife. "If you can harass the first bird and don't allow him to habitate, you can find some success and they will go elsewhere. Cormorants become accustomed to any constant activity."

In Florida, where over 110 state parks and thousands of private ponds offer a variety of fishing preferences, the cormorant can be seen over salt water, fresh water, lakes, ponds, canals, backwaters, wetlands and land-locked estuaries and has adapted his behavior accordingly.

Clint Hulslander, Department of Interior officer, has observed cormorant activities throughout Florida. The cormorants appear to be almost suburbanite in their daily life. Nesting as far as 35 miles from their perching and feeding sites, they commute in large flocks that increase in size as more nesting sites are passed en route to the feeding grounds. At their destination, one bird will dive into the water, scattering the school of fish. The rest of the flock then peels off in quasi-military fashion, bombarding the fish. Another learned behavior of the cormorant is the herding of baitfish like cattle onto a shoal or dead-end channel, and in rotation, annihilating the entire school.

Hulslander observed that is the birds arrive and leave as on a daily schedule. Feeding is done mostly in the morning and in a short period of time. The rest of the day is spent "relaxing in the sun." He says the cormorant is "used as a barometer" by wise fishermen, both bait and sport. Where there are cormorants, there are baitfish, and baitfish mean gamefish are nearby to feed on them.

Cormorants have become out of balance due to the byproducts and endeavors of Man. Their natural predators have been depleted along with the cormorant, but the recovery rate of these —otters, eagles, hawks and gulls— is much slower. The cormorant is also a predator, the kind of role historically misunderstood by humanity. We can look at our past and see how our fears, fueled by ignorance of the situation, led us to destroy predators perceived as the Devil's disciples. Research and observation of the astounding intricacies of Nature have led to total reversals of public opinion.

Bats, long thought synonymous with Dracula, are now known to be essential pollinators and seed-dispersers for reforestation. The "big bad wolf" is welcomed as a check for maintaining deer population, while whitetail deer have been called "rats with antlers" due to their overpopulated numbers and their newly brazen behavior. The lynx, hunted fiercely towards extinction, is now reintroduced as the farmer's friend in rodent domination. There is no animal on the earth today who is not managed or influenced by humanity in some way.

The cormorant is a problem of varying degrees, depending upon factors such as size and depth of the body of water, the climate, the condition of his natural habitat, the availability of his normal diet— baitfish, as opposed to freshly stocked fingerlings. My studies have shown me that the larger and more free-flowing the body of water, the less likely that cormorants will be a problem. It is difficult but possible to deter them without depredation. As a last resort, highly regulated and strictly enforced depredation methods could be used to restrict the population.

But even if all cormorants were destroyed, what about the pelicans? They too interfere with fishermen, as do otters, eagles, ospreys, alligators... the situation is far too complex for any simplistic solution. Meanwhile, the research on this bird continues. The cormorant helps us to read the health of the waters we treasure for the fish we seek. The deformities found amongst fledgling cormorants today could indicate bad times ahead for the fisherman. The toxins and pollutants that cause the crossed bills and eye problems are a far greater danger than the cormorants could ever be. We must direct our energies to the health of our waters.

Where there are cormorants, there are fish, fellow sports anglers. Think: is it the devil or the deep blue sea that evades your well-cast baits and lures? A knowledgeable fisherman with continually acquired skills is more than a worthy adversary for the black-feathered demon of underwater flight.

Photo of a cormorant, by David Lamfrom

Photo Credits— Solo cormorant photographs taken by David Lamfrom. Photo of perching cormorants at Matheson Hammock taken by Dr. Tom Kazo after Hurricane Andrew.