THE TRUMPETER SWAN is the largest species of native waterfowl now living in North America. It is of magnificent proportions, having a length of more than 5 feet and a wing spread of from 8 to 10 feet. Specimens weighing 32 pounds have been reported. The adult bird of this species has a pure white body, although its head and neck sometimes have a brownish stain, caused by the bird's habit of sticking its head and long neck down under water to feed. The bill and patch of feathers between the eyes and base of bill are black, as are also the legs.
This bird formerly bred from Fort Yukon, Alaska, and northern Canada south through British Columbia and Alberta to Montana and Wyoming, and eastward to Nebraska and Iowa. Each fall flocks are believed to have migrated through the Mississippi Valley to the Gulf of Mexico. With the coming of civilization and the settlement of its habitat by white men, the trumpeter swan, being a large conspicuous bird, was so greatly reduced in numbers by shooting that by 1929 only a few breeding pairs were known to remain in North America. In the whole United States less than a dozen pair were known to breed and most of these were located in or adjacent to Yellowstone National Park. The National Park Service, fearing that the species would soon become extinct, as had the great auk, passenger pigeon, heath hen, and other outstanding native North American birds, took steps to preserve it. For this reason, the Service in 1930 began a study to ascertain the location, numbers, and condition of the remaining birds of this species breeding in Yellowstone National Park and adjacent territory. Persons who lived the year round where a pair of swans had nested each year for the previous five seasons stated that during this entire time the swans had not succeeded in raising a single offspring to reach maturity.
George Wright and I decided to be on hand at the beginning of the nesting season and to keep a close watch during the critical incubation period and succeeding weeks, while the young were small, in order to find out as nearly as possible just what happened to the eggs and young of the swans. On June 9, 1930, when we reached the lake we found a pair of trumpeter swans present. A search with the binoculars revealed one of the birds, which later proved to be the female, sitting on top of a small mound of dead tules that apparently had been gathered together and heaped up by the swans to form a nest about the size of a haycock. (See illustration.)
FOR THE FIRST 24 HOURS of their lives, the cygnets stayed on the water or on their nest, but at the end of that period, choosing a small islet in the lake, the youngsters scrambled ashore. On land, in short grass, they made good progress, traveling about 6 feet in 20 seconds, and then squatted down apparently exhausted from the effort. Occasionally the cygnets stood erect extending their necks vertically, but most of the time their heads were held forward and their bodies prone as they slid gracefully through the grass, propelled by alternate strokes of their large and wobbly legs. Upon reaching a bit of open ground covered with a dense growth of short, green salt grass, the cygnets stretched out their necks and crouched down to rest in the warm sunshine. The soft, fine natal down with which the day-old cygnets were covered reminded me of a new, unused powder puff. (See illustration.)
The eye of the little cygnet in this illustration was such a rich dark brown that it almost appeared to be black. Its bill and feet were a pale flesh color, while the tip of the bill and toenails had a slight olive-yellow cast. In the bright sunshine, one of the cygnets appeared to be gray, and later we found some of them are gray instead of white when they are hatched.
Subsequent observations of this family showed that while the cygnets were young and in the downy stage the mother usually took the precaution to lead them ashore on a small islet well out into the lake rather than to chance their landing along the main margin of the lake where they might be captured by coyotes or other prowling land animals. As the youngsters grew older, they developed an initiative of their own and frequently led their parents about. When ever danger was close at hand the mother took her youngsters in tow and led them back to safety in the thick tules but if the danger was more remote the father usually went out to meet the enemy, honking a warning note to his family as he went. Upon hearing this signal, the young cygnets would scatter and hide separately in the thickets of dead tules, their rasping, squeaky call notes serving to keep the members of the family in touch with each other.
The National Park Service expects the full cooperation of all park visitors in protecting the trumpeter swans, especially during the nesting season. It is imperative that fishermen, photographers, and all persons not having actual business near nesting swans should remain away from lakes where the swans are known to nest. A relatively slight disturbance may cause the mother to leave the nest long enough for the eggs to become chilled and thus fail to hatch.
THE ADULT SWANS, like many parents, had considerable difficulty in keeping track of their young. When any danger from a nearby shore threatened, the mother swan usually led the family to safety while the father covered and brought up the rear. When danger from the air threatened, as in the case of ravens, hawks, or eagles, the parent swans gathered their young together into a compact flock which they kept in close formation between them. (See illustration.)
In one instance I was able to witness an enemy's attack. From the rear, it was warded off by the male spreading his wings and thereby covering and protecting the young, while the mother, in like manner, met the attack from the front. This teamwork of the parents proved to be effective and successful in warding off daytime attacks. As the cygnets grew larger, however, they became more independent and strayed farther from the protecting wings of their parents. Then it was more difficult for the parents to protect their offspring.
When the young cygnets were about the size of a mallard duck, some of them mysteriously began to disappear one by one. Therefore, on July 17, 1931, I moved to Trumpeter Lake and remained watching throughout the night. I found that the little family fed steadily until 8:30 o'clock in the evening and then went ashore. They remained there until something frightened them back into the water, but at 9 o'clock that evening, keeping in a small, compact flock in the tules, they went to roost for the night. Although I kept a continuous watch of their roosting site in the tules, I found the next morning that, between 9 o'clock the previous evening and 5 o'clock that morning, one of the cygnets had disappeared. Later observations showed that the pure white cygnets were usually the first ones to disappear. It is my belief that they were the first to be captured and killed because their white coloring was more readily seen in the dim light. It was noted that as long as the mother swan hovered her young at night they were safe, but as soon as they left her protecting wings and the home roost trouble began.
The old birds had considerable difficulty in getting their young trained to fly before the "freeze-up" in the fall. One observer reported that one day before a big storm he noted the old swans trying, without success, to induce a cygnet to fly.
Even though the young swans were able to fly in the fall, we found that danger still stalked them. Although they were protected by international, Federal, and State laws, investigation showed that some of the trumpeter swans were being shot. In the Red Rock Lakes area, which lies outside of Yellowstone National Park, we received reports of a hunter who shot and killed 16 young trumpeter swans in one hunting season. He claimed that they were China geese. So a campaign of education was instituted among sportsmen, and the National Park Service is glad to report that it now has the whole-hearted support of these men in pointing out the need for preserving this rare species. Finally, through the joint efforts of the late George M. Wright and of "Ding" Darling, who was then Chief of the Biological Survey, the critical area where the trumpeter swans congregate outside the park was purchased and established as a Federal migratory waterfowl refuge so that we now feel that the trumpeter swans are properly protected and slowly regaining their former numbers.
Last Updated: 01-Jul-2010