Quick Answer
Tundra swans migrate north in the summer to their breeding grounds in the Arctic tundra of Alaska, Canada, and Russia. They spend their summers nesting and raising young before migrating south again for the winter.
The tundra swan is a large migratory waterfowl species that breeds in the Arctic tundra during the summer months. In the fall, tundra swans migrate south to spend the winter in wetlands and estuaries along the Atlantic and Pacific coasts. Their annual migration covers thousands of miles between their Arctic breeding grounds and their more temperate wintering habitat. But where exactly do tundra swans go each summer to nest and raise their young?
Summer Breeding Grounds
Tundra swans nest in the far northern regions of Alaska, Canada, and Russia during the summer months of June through August. Their breeding habitat centers around shallow freshwater ponds, marshes, wet meadows, and shorelines in the tundra biome. Specific summer nesting areas include:
Alaska
– The Arctic Coastal Plain of northern Alaska
– The Yukon-Kuskokwim Delta
– The Seward Peninsula
– The Aleutian Islands
Canada
– The western and central Canadian Arctic islands
– The Northwest Territories
– Nunavut
– Northern Manitoba
– Northern Ontario
Russia
– The Taymyr Peninsula
– The coastal tundra of the Chukotka Peninsula
– Wrangel Island
– The New Siberian Islands
– Novaya Zemlya
The vast majority of the tundra swan population, estimated at over 100,000 birds, nests in the western Canadian Arctic. Other key breeding areas include the Seward Peninsula in Alaska and the Taymyr Peninsula in Russia.
Habitat and Ecology
Tundra swans seek out specific habitat features on their Arctic breeding areas during summer:
Shallow ponds and marshes – Their preferred nesting sites are in shallow waterbodies with abundant aquatic vegetation. These wetland habitats provide food and nesting materials.
Wet tundra meadows – Adjacent grassy tundra provides feeding areas for adults and hiding cover for young cygnets.
Low, open terrain – Treeless, low-lying tundra allows for good visibility to watch for predators. Small elevations and water provide shelter from wind.
Nearby feeding lakes – Large, deep lakes and ponds within a few miles of the nest offer good foraging habitat.
While on their summer breeding grounds, tundra swans feed heavily on aquatic vegetation and invertebrates to build up fat and nutrient reserves. This helps the birds survive the long migration south and winter period.
Some key foods eaten by tundra swans during summer include:
– Pondweed, muskgrass, sedges, horsetails, arrowgrass
– Aquatic insects like dragonflies and caddisflies
– Small mollusks like snails and freshwater clams
Nesting occurs from late May through July. Females lay 3-5 eggs in a mound of vegetation on the ground near water. Both parents incubate the eggs for about a month before they hatch. The young cygnets are able to swim and find food within 24 hours but are not able to fly for 2-3 months.
Before the cygnets can fly in late summer, the parents lead them overland to larger lakes where they build up fat reserves before migrating south in the fall. The long migration south begins in August and September as the Arctic winter approaches.
Winter Range and Habitat
When they leave their Arctic breeding grounds, tundra swans embark on migrations of 2,500-4,500 miles to reach their wintering habitat. Their winter range centers along the Atlantic and Pacific Coasts of North America.
Key wintering areas include:
Atlantic Coast
– Chesapeake Bay
– Currituck Sound
– Back Bay, Virginia
– Pamlico Sound
– Bodies of water along the North Carolina coast
Pacific Coast
– Puget Sound
– Willapa Bay, Washington
– Humboldt Bay, California
– San Francisco Bay
– Sacramento Valley
– San Joaquin Valley
– Salton Sea, California
The highest concentrations of wintering tundra swans, over 75% of the population, occur in the Chesapeake Bay region.
Tundra swans frequent shallow lakes, marshes, coastal bays, wet meadows, and agricultural fields while wintering. Some key habitat features include:
– Shallow, non-tidal ponds and lakes
– Fresh and saltwater marshes
– Flooded agricultural fields with leftover grains and vegetables
– Wet grasslands with rhizomes and tubers
– Estuaries and coastal bays with beds of submerged aquatic vegetation
Their diet shifts during winter to rely more heavily on roots, tubers, and agricultural leftovers. Winter foods include:
– Wild celery, widgeongrass, eelgrass
– Shoots, leaves, and rhizomes of marsh plants
– Leftover corn, wheat, soybeans in fields
– Tubers, roots, and shoots of sedges and grasses
The tundra swans follow the same migratory routes and return to the same winter sites every year. They start heading north again in late February and March to reach the Arctic in late May for the next breeding season.
Threats and Conservation
Historically, tundra swan numbers declined significantly from hunting pressure and egg collection. Populations dropped from over 100,000 birds in the late 1800s to fewer than 30,000 by the 1930s.
Conservation measures put in place last century allowed tundra swan populations to recover to over 100,000 today:
– The Migratory Bird Treaty Act of 1918 protected tundra swans and decreed hunting regulations
– Market hunting ended in the early 1900s
– National wildlife refuges were created in key nesting and wintering grounds
– Mandatory non-toxic shot requirements reduced lead poisoning incidences
Ongoing threats include:
– Habitat loss due to wetland drainage and development
– Disturbance from expanded oil, gas, and mining operations in the Arctic
– Pollution from lead ammunition still used in some areas
– Reduced food supplies from overgrazing and changes in agricultural practices
– Collisions with power lines during migration
However, coordinated management across their breeding and wintering range continues to maintain healthy tundra swan populations today.
Migration Routes
Tundra swans migrate along flyways across North America in a giant loop each year between their Arctic summer habitat and winter habitat in temperate coastal regions. The birds follow predictable routes aided by stopover sites along the way where they can rest and feed.
Fall Migration
In the fall, tundra swans gather in large flocks and leave their Arctic breeding grounds starting in late August and September. The fall migration route funnels down through central Canada and the United States.
Key stopovers sites along the fall flyway include:
– Northern prairie marshes and lakes in Canada
– The Great Lakes region
– Upper Mississippi River valley
– Great Salt Lake in Utah
– Summer Lake in Oregon
As winter approaches, the flocks split off towards either the Atlantic or Pacific coasts to reach their final wintering destinations from November to December.
Spring Migration
In February and March, wintering flocks begin migrating back north through the central United States.
Major spring migration stopovers include:
– Sacramento Valley
– San Joaquin Valley
– Klamath Basin on California-Oregon border
– Summer Lake, Oregon
– Snake River, Idaho
As the birds cross back into Canada, they follow prairie parklands through central Canada. From April to May, they reach their Arctic breeding grounds to complete the migratory cycle.
Banding studies show tundra swans exhibit a high degree of fidelity, returning to the same breeding sites and wintering grounds year after year. Their migrations exemplify the long-distance seasonal movements critical to the survival of Arctic nesting birds.
Population Status
Tundra swan populations are divided into two flocks that migrate along the Pacific Coast and Atlantic Coast:
Eastern Population
– Nest in eastern Canadian Arctic and winter along Atlantic Coast
– Population around 80,000-100,000 birds
– Concentrated in Chesapeake Bay region
– Generally stable but with declines in past decades
Western Population
– Nest in western Canadian Arctic and Alaska and winter along Pacific Coast
– Population around 18,000-20,000 birds
– Most winter in California’s Central Valley
– Declined in mid-1900s but rebounded in recent decades
The combined tundra swan population is estimated between 115,000-115,000 individuals. Overall, their numbers are considered healthy and sustainable today due to conservation efforts over the past century.
Maintaining sufficient breeding habitat in the Arctic and sufficient winter wetland habitat will be key to ensure tundra swans remain at stable population levels in the future. Any expansions of development in the Arctic in particular could pose long-term threats to their key nesting grounds.
Interesting Facts
Beyond their epic migratory journey, tundra swans exhibit some other fascinating traits and behaviors:
– Mate for life – Pairs stay together for many years and often migrate and winter together annually.
– Juveniles do not migrate north until 2-3 years old. Young birds will stay on the winter grounds during their first two summers.
– Molt all their flight feathers simultaneously during mid-summer, leaving them flightless for several weeks while their wings regrow.
– Male and female look identical. They can only be differentiated by size when side by side, with males measuring slightly larger.
– Known for their musical bugling calls that carry long distances.
– The nesting territory and mating rituals also involve a repertoire of snorts, barks, whistles, and grunts.
– Their huge wing muscles comprise up to 25% of their body weight, powering their 2,500 mile non-stop migratory flights.
– Spend nearly 50% of the year migrating between Arctic and temperate zones.
– Have complex families – may include one or more sets of parents and up to eight offspring that remain together for over a year.
Conclusion
In summary, tundra swans are long-distance migratory birds that breed during summer in the Arctic tundra regions of Alaska, Canada, and Russia. They migrate thousands of miles south each fall to spend winter along the Pacific and Atlantic Coasts of North America. Coordinated conservation efforts have recovered tundra swan populations from past overhunting and allowed them to thrive at around 100,000 birds today. However, potential threats from Arctic habitat loss underscore the need for continued preservation of their breeding and wintering grounds to maintain these majestic migratory birds into the future. Their epic seasonal journeys are a reminder of the interconnectivity between summer and winter habitats across continents.