The population of snow geese has exploded in recent decades. In the early 1900s, overhunting had decimated snow goose numbers, with only a few thousand remaining. But with changes in hunting regulations and agricultural practices, their numbers have rebounded in a major way.
In the opening section of this article, we’ll look at some quick answers to key questions about the snow goose population explosion:
Why were snow goose numbers so low historically? Overhunting in the late 1800s and early 1900s severely depleted the population. Snow geese were easy targets for hunters and their bright white plumage was popular for women’s hats.
When did their numbers start to increase? Snow goose numbers started to climb in the 1930s and 1940s after new hunting regulations limited harvests. The establishment of wildlife refuges also helped goose numbers recover.
How many snow geese are there today? Current estimates put the mid-continent snow goose population at around 15 million birds. In some nesting colonies, numbers have increased tenfold in just 30 years.
Why did their population increase so rapidly? A few key factors enabled the snow goose population explosion: reduced hunting pressure, ample food supplies from agricultural crops, and an ability to adapt nesting habits.
What are some concerns about the surging population? Too many birds are damaging fragile Arctic nesting grounds. Overgrazing impacts other bird species and reduces plant diversity. Goose droppings can degrade water quality.
Historical Context and Hunting Pressure
Snow geese have not always been so numerous across North America. In fact, uncontrolled hunting in the late 19th and early 20th centuries decimated their numbers.
Back in the 1880s, there were an estimated 20,000–30,000 snow geese nesting on Wrangel Island off the coast of Siberia. This was one of two key nesting sites for snow geese, along with Canada’s Baffin Island. Over the next few decades, market hunting harvested snow geese by the thousands. Their bright white plumage became a prime decoration for women’s hats.
By 1916, Wrangel Island’s snow goose population had plunged to just 288 nesting birds. On Baffin Island, numbers dropped to between 2,000 and 3,000 geese. Overall, it’s estimated that the total mid-continent snow goose population may have dwindled to fewer than 3,000 birds.
This overhunting clearly took a major toll on snow goose numbers. But what enabled the population to start recovering? Changing attitudes and regulations helped snow geese bounce back.
New Protections and Refuges
In 1916, the United States and Canada signed the Migratory Bird Treaty, which prohibited the spring hunt of migratory birds. This offered the decimated snow goose population some much-needed relief from hunting pressure.
Additional protections came in 1975 when snow geese were listed under the Migratory Bird Treaty Act. This federal law implemented hunting restrictions such as daily bag limits.
Snow geese also benefitted from wildlife refuges established starting in the 1930s. Federal, state, and provincial refuges protected vital snow goose nesting grounds. Snow geese received sanctuary from hunters on these lands.
Wrangel Island became a preserve in 1976. And in the Canadian low Arctic, Queen Maud Gulf Migratory Bird Sanctuary was founded in 1961. This sanctuary provides a safe nesting area for over 2 million snow geese.
Reduced hunting and expanded refuges gave snow goose numbers a chance to start recovering. By the 1960s, the population had rebounded to around 800,000 birds. And the explosion was only just beginning.
Changes in Agriculture and Foraging
Another major factor in the snow goose population boom was the increased availability of forage crops on their migration routes and wintering grounds.
In the mid-20th century, important agricultural changes took place across North America:
- Widespread irrigation provided reliable water for crops.
- Fertilizers boosted crop yields.
- Big machines enabled large-scale farming.
As a result, fields grew larger and croplands expanded. Snow geese started finding abundant food resources along migration pathways and on wintering grounds. These agricultural lands provided nourishment in the form of waste grains like corn, wheat, rice, and soybeans.
Some key wintering sites with prime forage for snow geese include:
- Central Valley of California
- Texas Gulf Coast
- Coastal marshes of Louisiana
On these winter habitats, snow geese can gorge on agricultural crops to build up fat reserves for the spring migration. These augmented food supplies support higher survival rates.
There’s also evidence that snow geese have increased their consumption of farm crops over time. Researchers in Texas examined snow goose diet from 1975 to 2006. They found that the proportion of sorghum in the diet rose from 2-12% to 33-40% over this period. Easy access to these nutritious crops boosts geese survival.
Adaptations in Nesting Behavior
Snow geese have also adapted some of their nesting behaviors in ways that increase nest success and recruitment of young.
Starting in the 1950s, some geese began to establish nest colonies in coastal marshes rather than inland on Arctic tundra. These lower elevation sites tend to be warmer with fewer predators.
Snow geese also adjusted their breeding timing. Birds that nest in coastal marshes lay eggs up to 1-2 weeks earlier than those nesting in colder, higher elevation tundra habitats. Earlier breeding improves chances for goslings to survive.
Finally, snow geese shifted from dispersed solitary nesting to dense colonies with synchronized breeding. In some cases, over 90% of adults may attempt to breed in a given year. More parents mean more offspring added to the rapid population growth.
Current Status and Concerns
Thanks to reduced hunting pressure, abundant forage crops, and flexible nesting strategies, snow geese have flourished beyond what anyone could have imagined a century ago.
But just how many snow geese are there now across North America? And is this population explosion actually problematic in some ways?
Population Size
According to surveys by the U.S. Fish and Wildlife Service, the mid-continent snow goose population has swelled to an estimated 15 million birds today.
That’s up from fewer than 3,000 around 1916 after overhunting had decimated the population. This represents a 5,000-fold increase over the last century!
Some individual nesting colonies have grown tenfold in just 20-30 years. For example, the nesting colony at Wrangel Island off Siberia rebounded from 2,000 birds in 1975 to over 200,000 by 2010.
The following table summarizes current snow goose population estimates by region:
| Region | Population Estimate |
|---|---|
| Mid-continent (includes lesser snow geese) | 15 million |
| Western Arctic (greater snow geese) | 200,000 |
| Wrangel Island, Russia (lesser snow geese) | 200,000 |
These numbers make it clear that snow goose populations are now many times larger than they were even just 50 years ago.
Damage to Tundra Nests
But there can be downsides to populations that are overly abundant. One issue stemming from the mid-continent snow goose explosion is damage to fragile Arctic nesting habitats.
In their haste to build nests and raise young, large flocks of geese can degrade tundra vegetation. Their grubbing uproots plants, exposes soils, and leads to erosion.
One study in Canada found that within just 5-10 years of colonization by Dense nesting snow geese, up to 40% of vegetation may be lost through overgrazing damage. Lichens and mosses are especially slow to recover from trampling impacts.
Overabundant birds also deposit massive amounts of feces that can alter soil nutrients and pollute nearby lakes. One researcher measured summer input of snow goose poop at 400-600 kilograms per hectare!
Their huge numbers enables snow geese to decimate preferred foods like cotton grasses. This forces them to switch to less nutritious plants. Chick growth and survival suffer as a result.
Ultimately, degraded nesting habitat could reduce goose recruitment. But for now, the booming population outpaces any declines so far seen.
Threats to Other Species
Overgrazing of Arctic plant communities also impacts other bird species that share these nesting grounds. The lesser snow geese and Ross’s geese that have ballooned in number compete with other birds for food and nest sites.
Declines have been noted in nesting shorebirds, ducks, jaegers, and swans where snow goose numbers have soared. For example, breeding Pacific black brant are a Species of Special Concern in Canada largely due to competition with booming goose populations.
Snow geese also trample the above-ground nests of dolphin gulls, parasitic jaegers, and plovers. These species suffer lower reproductive success as a result of habitat degradation from overabundant geese.
Management and Control Measures
Wildlife officials have implemented various management actions aimed at curbing mid-continent snow goose numbers. These measures try to strike a balance between preserving population health and minimizing habitat damage.
Some key management strategies include:
Relaxed Hunting Regulations
Since the late 1990s, wildlife agencies have allowed more liberal snow goose hunting. This includes use of electronic calls, unplugged shotguns, and extended shooting hours. The goal is to increase daily bag limits and goose mortality.
Spring conservation hunts starting in the 2000s also target snow geese just before they migrate north to breed. By reducing adult numbers, fewer birds reach the tundra to degrade sensitive nesting habitat.
Habitat Modification
In some areas, land managers are altering snow goose habitat to disperse dense colonies. Efforts may include controlled burns, herbicide applications, or planting trees and shrubs.
For example, planting willows on barge islands used by foraging geese provides cover for predators like foxes to increase goose mortality.
Egg Addling
Egg addling involves shaking eggs or coating them with oil to kill the embryos prior to hatching. When done on a large scale, this reduces the number of goslings that can contribute to population growth.
On Wrangel Island, addling the eggs of up to 10% of nests per year has kept colony expansion under control.
Support for Predators
In some cases, wildlife officials take measures to support predator populations that provide natural control over snow goose numbers.
Nest platforms and feeders can boost raven and gull populations. And construction of artificial dens helps sustain Arctic fox populations that prey on eggs and goslings.
The Future of Snow Goose Management
The mid-continent snow goose population clearly recovered from the brink of extinction in the early 1900s. But wildlife managers now face the challenge of controlling their overabundance.
Looking ahead, it will be critical to employ thoughtful science-based policies that strike a sustainable balance. The goals are to:
- Preserve healthy snow goose numbers
- Protect their fragile Arctic ecosystems
- Support biodiversity of other tundra-nesting species
With careful ongoing management, snow goose populations can be sustained at levels that safeguard their future while minimizing environmental damage.
The snow goose population explosion makes for an ecological conundrum. But with collaboration between scientists and policymakers, solutions are within reach to benefit both snow geese and their nesting habitats.
Conclusion
In summary, overhunting devastated mid-continent snow goose populations in the late 1800s and early 1900s. Only a few thousand birds remained by the early 20th century.
New hunting regulations, refuges, ample forage, and flexible nesting behaviors enabled snow geese to rebound in a major way. Estimates now put the population at around 15 million.
But such overabundance comes at a cost, degrading fragile Arctic nesting grounds and harming other bird species.
Wildlife officials now face the complex challenge of managing booming snow goose numbers. With thoughtful policies and science-based habitat management, sustainable populations can be maintained while protecting Arctic ecosystems.
The snow goose population explosion makes for a remarkable wildlife conservation success story. Ongoing stewardship efforts can ensure these birds continue thriving while nesting habitats remain healthy.
