Common Loon
Gavia immer

The Common Loon population in Yellowstone NP continues to fluctuate from year to year. There were nine nest attempts in 2006, yet only six loonlets managed to reach fledgling age, compared to eight nest attempts fledging four young in 2005, and nine nest attempts fledging three young in 2004. Many of the nesting loons had to deal with variable water levels and shorelines as a result of the odd weather conditions.

Drought is also playing a role at some sites. A total of 39 adults were found in the park in 2006, compared to 42 adults in 2005, and 44 adults in 2004. These adult numbers have reliably ranged between 34 and 51 individuals over the last eighteen years. Yearly fluctuations in adult numbers and in the production of young are the result of variable weather conditions. The moderate loon production and the low adult numbers continue to be a reflection of weather-related conditions.

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Harlequin Duck
Histrionicus histrionicus

The Harlequin Duck population in Yellowstone NP continues to maintain itself and is only mildly variable from year to year, with generally 22–26 pair residing in the park. Monitoring adults is the most effective method of keeping track of population vigor and trends. Monitoring annual productivity is not cost effective, as data collection is extremely time-consuming and difficult due to the remoteness of many of the areas in which harlequins are found. Productivity is extremely variable from year to year and is highly influenced by weather, such as flooding.

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Osprey
Pandion haliaetus

The Yellowstone National Park Osprey population continues to show signs of a population caught in a serious downward trend over the last six years. Small age cutthroat trout , a major food source for Ospreys have severely declined on Yellowstone Lake, adding to existing weather variables that influence production. In 2006, a mere 23 young fledged from 41 nests, compared to only 15 young fledging from 48 nests in 2005, and 19 young fledging from 54 nests in 2004 (Figure 11). This represents the fourth lowest production experienced in the last 20 years of collecting detailed osprey population data. A series of strong winds and wet weather throughout the summer caused some of the nests and/or nest trees to fall to the ground resulting in high failure rates again this year (Figure 12), but territorial occupancy was documented as noticeably declining mainly on Yellowstone Lake. Tree nest site instability coupled with weather continue to play a major role in influencing Osprey productivity in the park. Although Frank Island, a major Osprey production area on Yellowstone Lake, burned in 2003 again only one pair nested on Frank Island in the last three years and fledged only one young per year. At one time (e.g. 1994) Frank Island had as many as 25 nesting Osprey pairs and fledged a high of 28 young. The incidence of Bald Eagles taking over Osprey nest sites was not noted this year, but has been observed on numerous occasions. Monitoring the population dynamics of Ospreys and other piscivorous bird species is especially important as we chart lake trout numbers over time.

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Trumpeter Swan
Cygnus buccinator

The Yellowstone National Park resident Trumpeter Swan subpopulation continues to show signs of a species at risk of local imperilment. Traditionally, the Centennial Valley of Montana has been a hot spot for cygnet production in the greater Yellowstone area. Swan recruitment from outside of Yellowstone National Park is a critical factor in maintaining the resident swan population. Historically, swans that died in the park (mainly through predation) were eventually replaced by swans from outside the park (namely the Centennial Valley). However, management events over the last two decades have led to a reduction of breeding swans particularly outside the Park, coupled with low numbers of fledged cygnets throughout the greater Yellowstone are cause for serious concern.

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Peregrine Falcon
Falco peregrinus

On August 26, 1999, the Peregrine Falcon was delisted or "removed" from a list of threatened and endangered species. Under provisions afforded by the Endangered Species Act, even though this species is no longer officially listed as endangered, it still needs to be monitored closely to ensure its recovery.

The Peregrine Falcon has been delisted or "removed' from the list of endangered species and is now managed as a species of special concern. Yellowstone continues to be a stronghold for peregrines in the Nortern Rockies. One new eyrie was found in 2006 bringing the total number of peregrine eyries in YNP to 31. As a result of finding this additional peregrine eyries a total of 50 young fledged in 2006, making this the highest number of fledged peregrines ever recorded in history of Yellowstone National Park.

 Monitoring peregrines eyries is a time consuming task. The year 2006 marked the seventh year since delisting, and Yellowstone data supports the contention that peregrines are on the road to full recovery. A future sampling scheme will be developed, in which perhaps only one third of all known eyries in the park will be checked each year, thus completing a full parkwide production survey every three years. This will allow time to check cliffs for new eyries and move on to other projects.

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Bald Eagle
Haliaeetus leucocephalus

A translation of the scientific name of the Bald Eagle (Haliaeetus leucocephalus) literally means "white-headed sea eagle." The Bald Eagle is endemic to North America, and the national symbol of the United States of America. Previously classified as an endangered species under the provisions of the Endangered Species Act (1973), as of 1989, recovery objectives had been reached in the Greater Yellowstone Ecosystem and the Bald Eagle was removed from the threatened species list in August 2007.

Adult Bald Eagles are relatively easy to identify. They are chocolate brown bodied raptors with a pure white head and tail, including an unfeathered tarsi and a massive yellow beak. It typically takes Bald Eagles 5 years to acquire definitive adult plumage. Immatures come in a variety of plumages based on age. Darker-headed, darker breasted birds being of younger age classes, with 3-4 year old birds being lighter colored in the head, beak and tail. Adult male Bald Eagles are smaller than females, weighing 8-9 pounds compared to 10-14 pound females.

Current population figures indicate there are 34 eagle nests that produced 26 eaglets in 2007. Some eagle territories are experiencing nest instability due to large numbers of trees that are falling as a result of the 1988 fires. Weather continues to play a critical role in eagle production and most Yellowstone bird production for that matter, since the Yellowstone Plateau is notorious for its weather extremes.

Bald Eagle habitat, movements, and food habits change dramatically from summer to winter. Nesting usually begins in late February to mid-March. Eagle chicks hatch from the large platform tree nest in late March-early April, while fledglings leave the nest somewhere between late June and late July depending on the elevation of the nest. In the summer, Bald Eagles are often found in close association with water, however they can be found venturing over mountain meadows and even the summits of mountain peaks on occasion. Their summertime prey is primarily fish and waterfowl. As winter approaches, immature and sub-adult eagles typically leave the park. Research has found many eagles in these young age classes migrate in a westerly direction often ending up occupying coastal and interior winter habitat that ranged from northern California through Oregon. Some Yellowstone adult Bald Eagle pairs spend the entire winter in close proximity to their nesting territory, other pairs migrate to lower elevations such as the area around Gardiner, Montana to secure food. Winter habitat for Bald Eagles often centers around ungulate winter ranges and watercourses free of ice. Carrion and waterfowl are the primary food items taken by Bald Eagles in the winter. Fish can be taken as a winter food item, but are not as easily available as in the summer due to the icing of lakes and rivers. By February eagle pairs return to their nesting territory thus completing a year in the life of the Yellowstone Bald Eagle.

Finding Bald Eagles in Yellowstone
Where to Look:

Summer - Yellowstone Lake, Hayden Valley, Madison River.

Winter - Madison River, Gardner River, Hayden Valley.

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Whooping Crane
Grus americana

One endangered bird species previously occurred in the greater Yellowstone area: the whooping crane.

The scientific name of the Whooping Crane Grus americana, literally translated means "American crane." While the Whooping Crane is endemic or native to North America, it is without question one of the most endangered and spectacular of the 15 species of cranes found in the world. The Whooping Crane is currently classified as an endangered species under provisions established by the Endangered Species Act of 1973 and administered by the U.S. Fish and Wildlife Service

Adult Whooping Cranes are easily identified by their strikingly bold white body plumage, black wingtips, black facial feather markings, red crown patch, black legs and feet, yellow-black bi-colored bill, and yellow eyes. The Whooping Crane is the tallest bird in North America, standing 5 feet tall, with a wingspan that measures 7 feet in length. In flight these birds are quite easy to identify with the bold black and white plumage, extended neck, and trailing legs. Males are slightly larger than females both in size (although difficult to judge) and weight ( males weigh 16 pounds and females 14 pounds).

Whooping Cranes get their name from their loud, distinctive "whooping" call emitted by the male or female or simultaneously by both members of a pair. Calling is a method of communication in cranes and is used to reinforce pair bonds, defend territories, detect danger, or consequently sound alarm.

Historically speaking, fossil evidence of Whooping Cranes in North America dates back several million years, and shows these birds once occurring in a large geographical area extending from central Canada to central Mexico, and from Utah to the Atlantic coast.

Information is sketchy as to whether or not Whooping Cranes ever nested in Yellowstone National Park. Whooping Crane numbers were probably never superabundant over the last 200 years, however there was still a sizeable North American population remaining up until the 1860's. By the 1890's the Whooping Crane was nearly extirpated from most of its range, with only two flocks remaining by 1939 - a relic non-migratory flock in southwestern Louisiana, and a migratory flock that nested in west central Canada and wintered in southeastern Texas.

The decline of the Whooping Crane in North America was primarily due to an expanding human population. In the late 1800's and early 1900's there was a rapid western expansion of the continent by pioneers and European settlers. Shooting played a major role in the decline of these birds, however agricultural practices such as tilling prairies and draining marshes also contributed to the decline. As these crane numbers plummeted, demand for rare species such as the Whooping Crane increased further through demand created by taxidermists, private and museum collectors, and hunters. By 1950, the entire Louisiana Whooping Crane population had totally disappeared. All that remained was a migratory wintering Texas population numbering about 15 individuals, yet the location of the nesting grounds remained unknown. In 1954, that mystery had been solved, when a helicopter crew returning from a wildfire discovered three Whooping Cranes in Wood Buffalo National Park. In 1955 Robert Porter Allen and Robert Stewart confirmed the location and discovered a Whooping Crane nest. The riddle had finally been solved and this marked a critical juncture in the conservation of the Whooping Crane.

The isolation of Wood Buffalo National Park coupled with creative captive propagation techniques played a critical role in bringing the Whooping Crane back from the brink of extinction. Biologists learned over time that Whooping Cranes which traditionally lay two eggs, only are successful in fledging one young. Therefore one egg was removed from wild nests and hatchlings from this experiment formed the basis for the captive flocks we find in existence today. In 1999, the North American Whooping Crane Population was estimated to be 183 birds in the wild, 99 birds in captivity, and 4 birds found in the Rocky Mountains classified as "experimental-nonessential".

Whooping Cranes in the Rocky Mountains

A cross-fostering experiment to create a new migratory flock of Whooping Cranes took place in the Rocky Mountains in 1975. Under the direction of the U.S. Fish and Wildlife Service and the Canadian Wildlife Service, researcher Rod Drewien transported Whooping Crane eggs from Wood Buffalo National Park in Canada and placed them under incubating Sandhill Cranes on Gray's Lake National Wildlife Refuge in Idaho. The main focus of the cross-fostering experiment was to have Sandhill Crane adults hatch and raise Whooping Crane young, thus leading immature Whooping Cranes on migration to a Sandhill Crane winter safe haven known as Bosque del Apache National Wildlife Refuge in New Mexico.

Initially, the cross-fostering experiment showed promising signs, but eventually problems began to develop. Of particular concern was high crane mortality, and Whooping Crane mating behavioral problems associated with the experiment. However, a significant amount of valuable information was gained as a result of this study. In summary, a total of 289 eggs were removed from the wild for this experiment, which resulted in the Rocky Mountain Whooping Crane population reaching a peak of 35 subadult/adults in 1985. In 1999, only two adults survived from the original Gray's Lake experiment, and resided within the Greater Yellowstone. These birds were not paired. One bird resided in a remote area of Yellowstone National Park for years, and the other frequented the Centennial Valley of Montana. On March 15, 2000, a significant event took place in the history of Yellowstone ornithology, when the lone whooping crane that had resided in Yellowstone National Park for years, died from a collision with power lines in the San Luis Valley of Colorado. Therefore, only one adult from the Gray's Lake experiment remains alive today. This bird frequents the Centennial Valley of Montana.

In addition, the Yellowstone National Park bird program has been monitoring a "sandhill-whooper" hybrid since it was discovered in 1992. The bird was frequently seen with a Sandhill Crane and was being carefully monitored. This bird had significant scientific value, since it allowed scientists an opportunity to determine whether it could reproduce successfully in the wild. This is an important piece of information could have assisted Whooping Crane recovery efforts in the future. However, the hybrid crane could not be located in Yellowstone National Park in 1999, and is presumed dead.

Another Whooping Crane "experiment" occurred in the Rocky Mountains in 1997/1998 that had a bearing on Yellowstone National Park. Four young Whooping Cranes raised in captivity at Patuxent Wildlife Research Center in Maryland, were transported to a ranch in eastern Idaho as part of an experiment to learn how to establish a new migratory flock of Whooping Cranes in North America. The birds were trained to follow an ultralight aircraft. In the autumn of 1997, these cranes traveled from eastern Idaho to Bosque del Apache NWR in New Mexico following the aircraft. Two of the cranes were killed by predators on the wintering grounds. The two remaining "ultralight"cranes began their spring travels north on March 5,1998, staging for a month in the San Luis Valley of Colorado. Once moving again, the birds started to have problems with fences and power lines. Collisions with wires continues to be the greatest cause of mortality for immature Whooping Cranes. Therefore, these cranes were quickly recaptured and released into a safer environment in Yellowstone National Park. In May1998, without little forewarning, two "ultralight" Whooping Cranes were released in the Slough Creek area of the park. This area where the cranes were released proved to be troublesome. Large numbers of visitors were coming in close contact with the birds creating further imprinting problems. Later that summer, an effort was made to recapture the cranes, but only one "ultralight" bird was caught and transported to a remote area of the park. The other crane remained in the vicinity of Slough Creek until it migrated that fall out of the area. Both birds returned to the wintering grounds in New Mexico. Then in the spring of 1999, one bird died in northern Utah from undetermined causes due to the condition of the carcass, leaving a lone survivor residing in eastern Idaho for the summer.

As it now stands, there are only two Whooping Cranes remaining in the Rocky Mountains. One adult from the Gray's Lake experiment, and one "ultralight" crane. The prognosis for the Whooping Crane in the Rocky Mountains does not look promising. Whooping Cranes are expected to disappear from the Greater Yellowstone landscape in the near future. The Whooping Crane Recovery Team has abandoned efforts to establish this species in the Greater Yellowstone and in the Rocky Mountains in the immediate future, citing mortality, disease, habitat, pair-bonding, and imprinting issues to name a few. In September 1999, the Whooping Crane Recovery Team recommended the Wisconsin-Florida corridor as the best experimental site for establishing a new migratory flock of Whooping Cranes. Experimental efforts will begin in the year 2000.

Sources:

• Yellowstone Bird Report 2006
• Cranes: Their Biology, Husbandry, and Conservation; Ecology,Status and Conservation by Curt Meine and George Archibald (Hancock House, Blaine,Wash..1996).
• International Crane Foundation Website at www.savingcranes.org

Field Checklist of Yellowstone Birds