When groundbreaking German naturalist Georg Stellar first landed on Alaska’s western shores in 1741, he sailed not far from the current day Izembek National Wildlife Refuge, located at the tip of the Alaska Peninsula. Steller would have discovered an Izembek not much different than what we see there today: a global biodiversity stronghold, with more than just seven swans a-swimmin’ through its lagoon.
Let’s carol our way through seven fun facts about the iconic resident Izembek tundra swan.
1. On the first day of Christmas my true love said to me: the Izembek tundra swan is the world’s only non-migratory population of swans.
Resident Izembek tundra swans are fully unique because, unlike every other swan species worldwide, they remain in and around Izembek’s rich lagoons year-round. They endure harsh winter conditions and blasts of seasonal typhoon winds instead of migrating elsewhere.
This is a testament to the quality of Izembek’s abundant eelgrass lagoons which sustain these swans throughout every season. Residents live their entire lives nesting and raising their young on and around the narrow isthmus at the heart of the refuge that separates the Izembek and Kinzarof Lagoons. Geothermal activity keeps several nearby marine lagoons from completely freezing over which the swans can use if others freeze over.
2. On the second day of Christmas my true love said to me: Izembek tundra swans are voracious eaters.
Dwarf shrubs like blueberry and crowberry, common in the tussock-lichen tundra, produce large crops of berries that swans devour. More importantly perhaps, are the lush beds of eelgrass. Lakes with outlets capable of supporting salmon runs tend to be nutrient-rich and produce the stout growth of sea grasses found in the refuge. These grasses are favored by tundra swans for nesting, molting, and raising their young.
Thanks in part to the surrounding volcanoes that have bellowed ash into the soil system across the ages, these are among the largest eelgrass beds in the world. It takes a special combination of wetland chemistry, hydrology, and edaphic (soil quality) factors for eelgrass to grow and persist. Conditions appear somewhat perfect in Izembek, so much so that the Izembek Lagoon and adjacent portions of the isthmus have been designated as a Wetland of International Importance under the Ramsar Convention, the first in the United States and only in the state of Alaska to be designated as such.
3. On the third day of Christmas my true love said to me: don’t mess with swans!
Tundra Swans are known to stand their ground and display extremely aggressive behavior if provoked, especially during breeding season. Swans will hiss, bite, and flap their massive wings — a 5.5-foot wingspan, which is actually the smallest among large swan species — imposingly at any who get too close for comfort.
Outside of the breeding season, however, these swans are quite sociable and can be found in flocks of upwards of one hundred individuals.
4. On the fourth day of Christmas my true love said to me: “I love you” and tundra swans are fierce parents that mate for life.
Resident pairs operate as a team to rear chicks. The female incubates the eggs while the male keeps on constant lookout for predators. Stealthy predators must capitalize on the absence of aggressive parents who otherwise very successfully stand their ground to prevent predation attempts on their young.
If both parents are distracted, usually by a territorial dispute, predators can opportunistically invade nests. Brown bears are the main source of nest failures. They cruise through the isthmus, raiding and destroying nests in search of eggs and chicks.
On the fifth day of Christmas my true love said to me: Compared to the approximate 150,000 tundra swans found in Alaska, the Izembek resident swans are a small, unique sub-population.
These swans make up the most southerly and westerly breeding tundra swans in North America. Biologists use spring aerial surveys to identify critical nesting habitats and estimate annual populations. The most recent survey was conducted in 2022 and reported 72 non-migratory Izembek swans in breeding pairs and 48 birds in flocks, likely indicating non-breeding birds.
Since the refuge began counting and monitoring resident swans in 1978, the Izembek area has consistently supported low swan densities, with overall long-term trends in declines and occasional short-term drops, followed by gradual rebounds. In fact, these swans have experienced about a 90% decline since the 1980s. This requires further study, as the reason for decline is not well understood. Biologists have observed, however, that increased human activity and an expanded off-road vehicle trail system are at least in part to blame.
6. On the sixth day of Christmas my true love said to me: healthy adults have very few natural predators.
Izembek tundra swans have an average lifespan of around 10 years. About 15% of adults die each year from various causes. Reports of large predators like brown bears, golden eagles, and wolves have been documented killing adult swans, but most deaths are caused by humans. Hunting and the accidental killing of swans while hunting other birds, lead poisoning from shotgun ammunition left in their environment, and habitat encroachment are the biggest threats for most swan populations.
7. On the seventh day of Christmas my true love said to me: building a road through Izembek would be catastrophic for resident Izembek tundra swans.
If a road was built through the narrow isthmus of Izembek NWR, as is currently planned, opportunities for swans to escape or simply avoid human threats would be limited. Adults reliably leave nests in response to approaching humans, even when people are over a mile away, and rarely return if activity remains. Refuge adult swans with cygnets have been recorded moving up to 6 miles away from brood-rearing waters in response to human activity.
Like many other roads in this area, off-road use would likely develop as a maze of informal spur roads as people seek closer wildlife viewing or hunting opportunities. This would extend human disturbance effects farther into swan habitat and would crush nest success.
Defenders filed a lawsuit against the federal government to keep a road out of Izembek and protect the countless migratory and resident birds, mammals, and fish. There are more than just nine ladies dancin’ in celebration of these incredible swans, and hopefully you’ll join us in celebrating and protecting them for years to come.
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