A Blizzard of Geese

By Dianne Van Dien | November 1, 2024
From Missouri Conservationist: November 2024
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Snow Geese
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A Blizzard of Geese
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Every fall, millions of snow geese leave their Arctic nesting grounds and make their way south, many heading through the Midwest and stopping in Missouri. Tens of thousands gather in wetlands across the state from Loess Bluffs National Wildlife Refuge (NWR) in the northwest to Duck Creek Conservation Area (CA) in the southeast.

Whether you’re watching 40,000 or 200,000, the sight of so many geese is stunning. The sound of their voices permeates the air as the flocks gather and maneuver.

If you arrive at a wetland in late morning, snow geese will be returning from feeding in nearby fields. A floating mass of white birds may already be forming in an open pool. Now and then hundreds of geese will rise up at once and get louder as an eagle passes overhead. At the same time, more geese will be flying in to join those on the open water. Calling to each other, they’ll suddenly descend, twisting their bodies back and forth, sometimes turning completely upside down, to slow their speed before they splash onto the water’s surface. Adjust your binoculars to look higher and farther, and you will see strands of geese at different altitudes stretching across the sky. Eventually the sky will empty, and the entire wetland pool will be covered in geese, packed shoulder to shoulder.

Estimating the number of geese — not just on individual wetlands, but of the snow goose population as a whole — is something biologists have been doing for decades, and the data they’ve collected show that there are far more snow geese today than there were in the middle of the 20th century. For some species, this increase would have been celebrated, but for snow geese, that is not the case.

“On one side of the coin, it is amazing to see that many birds all in one location,” says Frank Nelson, MDC wetlands systems manager. “On the other side of the coin, there’s been a lot of concern and effort put into trying to keep these populations from running away.”

Monitoring Goose Populations

Wildlife agencies in Canada and the U.S. work together to monitor and manage Arctic-nesting geese whose annual life cycles span both countries. Snow geese are managed as separate populations based on breeding area and migration route. While all have seen growth, the midcontinent population (the ones we see here in the middle of the U.S.) has had the biggest increase. In the 1970s, estimates for midcontinent snow geese averaged about 2 million, but in the 2000s, yearly estimates were ranging from 11 to 18 million.

Snow geese are not the only Arctic-nesting geese that are monitored and migrate through our state. We also see flocks of Canada geese and greater white-fronted geese. And mixed in with the migrating snow geese are Ross’s geese. These geese look very much like snow geese but are smaller (about the size of a mallard). They nest in the same areas as snow geese in the central Arctic, and while most Ross’s geese take a more westerly route, some migrate to the Midwest. Collectively, snow geese and Ross’s geese are referred to as “light geese.”

Although the Ross’s goose population is far smaller than that of snow geese, it has also seen phenomenal growth from an average of about 160,000 in the early 1990s to about 2.5 million in 2018.

Population estimates, past and current, can be found in an annual waterfowl status report provided by the U.S. Fish and Wildlife Service (USFWS) at short.mdc.mo.gov/4RV.

What’s at Stake?

Geese are herbivores, or plant eaters. They are considered grazers, but “snow geese have serrated, strong bills and tongues,” explains Andy Forbes, USFWS biologist, “which enable them to ‘grub’ more than other species of goose and take advantage of the roots of plants versus just grazing like other species of goose.”

Sprouts and plant roots provide snow geese with high-quality nutrition, but because they pull up the entire plant instead of just grazing, it takes longer for the habitat to replace the plants that the snow geese eat. Biologists are concerned about how the increase in snow geese will affect the tundra and salt marsh habitats where the geese breed. Over time, a larger breeding population can reduce the amount of ground cover and change the soil quality, ultimately damaging the Arctic habitat and causing problems for other species, such as shorebirds that rely on the vegetation for nesting cover.

What Caused the Population Growth?

During migration, birds burn a lot of energy. Unlike hawks and vultures, geese don’t glide as they travel but flap nearly constantly. Weighing an average of 5 pounds, snow geese need a lot of food if they’re going to make it from the Arctic to the wintering grounds and back. Surviving migration can be a major challenge.

“Geese and other waterfowl have comparatively large, powerful pectoral muscles made up of large proportions of aerobic (dark) muscle fibers that allow them to be strong fliers with great endurance,” Forbes says. “Their behavior on staging areas involves intensive feeding, which enables them to build fat stores, which power longer distance flights.”

As they travel, snow geese stop at wetlands on refuges and conservation areas, often leaving during the day to forage on waste grain in nearby agricultural fields. Before farming covered the Midwest, these fields were not there. Scientists believe that feeding on agricultural leftovers in Missouri and other states is the main reason why the snow goose population has seen so much growth. Extra winter food equals better survival.

Darrin Welchert, wildlife biologist at Loess Bluffs NWR, explains it this way: “It’s been one of those stories where the geese have figured out so well how to survive with feeding on waste grain as they migrate south, as the land’s been converted over the last 100 plus years from prairie to agriculture … Then [the population] boomed and they started eating themselves out of house and home [on the breeding grounds].”

Light Goose Conservation Order

In 1999, to help bring the snow goose population back to sustainable numbers, the U.S. established the Light Goose Conservation Order (LGCO), allowing snow and Ross’s geese to be harvested outside of the regular hunting season. Canada implemented a similar measure. The goal was to decrease the population by increasing the number of geese harvested each year. The dates and harvest limits for the conservation order are determined by each state to fit with local conditions. In Missouri, the LGCO begins after the other waterfowl seasons have ended and runs from February 7 to April 30. During this time, there is no daily bag limit or possession limit for light geese.

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Missouri’s Arctic-Nesting Geese
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Snow Goose

Anser caerulescens

Length: 28 inches (tip of bill to tip of tail)

Where: Statewide

The snow goose has two color forms: white morph and dark morph. Dark morph snow geese are often called “blue geese” and were thought to be a separate species until 1983.

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Canada Goose

Branta canadensis

Length: 24–48 inches (tip of bill to tip of tail)

Where: Common statewide on ponds, lakes, and marshes

Although some Canada geese migrate to and breed in the Arctic, many remain and breed in the U.S., including here in Missouri.

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Ross’s Goose

Anser rossii

Length: 23 inches (tip of bill to tip of tail)

Where: Statewide

In Missouri, most large flocks of snow geese also include a few Ross’s geese. Like snow geese, Ross’s geese also have a white and dark form.

To tell a snow goose from a Ross’s goose, look at the head and bill. A snow goose has a proportionately larger bill with a distinctive “grin patch” or black “lipstick” mark. A Ross’s goose has a more rounded head, a smaller bill, and little to no grin patch.

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Greater White-Fronted Goose

Anser albifrons

Length: 28 inches (tip of bill to tip of tail)

Where: Uncommon migrant statewide. More common in the western half of state

Adult greater white-fronted geese have white feathering around the base of their bill and black streaks or splotches on their bellies. Their calls are described as a high-pitched yelping, laughing sound.

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Snow Goose Range

Snow geese have three main populations: western, eastern, and midcontinent. These populations generally breed and migrate within their separate geographic groupings. The midcontinent population — the one we see in Missouri — breeds in northern Canada and along the Hudson Bay and winters mainly from Missouri to the Gulf Coast of Louisiana and Texas.

Where to See Snow Geese in Missouri

  • Loess Bluffs NWR
  • Nodaway Valley CA
  • Bob Brown CA
  • Swan Lake NWR
  • Fountain Grove CA
  • Grand Pass CA
  • Duck Creek CA
  • Otter Slough CA

The LGCO has been in place for more than two decades. Although the harvest rate increased after the conservation order was issued, it wasn’t enough to keep up with population growth. Snow goose numbers continued to rise, with the adult midcontinent population averaging around 17.5 million in the late 2000s and remaining relatively stable for nearly a decade. But in 2017, the numbers began to drop. In 2022 the midcontinent population was estimated at a little less than 5 million, similar to what the population had been in the early 1990s.

While snow goose numbers have declined, scientists do not believe the LGCO is the reason. They note that the adult survival rate still has not changed much, so the population decline cannot be from the number of geese that are being harvested. Instead, research indicates that fewer goslings are reaching adulthood, likely because the dense number of geese on the breeding grounds is taking its toll — there is less food for the offspring.

Some recent journal articles suggest that climate change may also be playing a role. With a warming Arctic, the vegetation emerges earlier in the season and may no longer be at the optimal stage for the growing goslings. A warmer climate can also cause cooler, wetter springs, which can delay nesting and reduce nesting success.

Adult survival is still high and harvest rates are not high enough to reduce the number of adults, so the LGCO will not change. Biologists will keep monitoring the situation and, if needed, update hunting regulations in the future.

For full details about goose population monitoring, research, and management history, visit the Arctic Goose Joint Venture website at agjv.ca.

Are We Seeing Fewer Snow Geese in the Midwest?

“This is complicated,” says Forbes. “The overall population has declined, but there are possibly more birds [snow geese] now in the Midwest during the winter than historically, as they are wintering proportionally more northward.”

Not all geese are going to Texas and Louisiana for the winter as they did in the past. Winter food (waste grain) is now available in states like Missouri and Arkansas, so the geese don’t need to fly all the way to the Gulf Coast to survive the winter.

How Do Snow Geese Affect Wetlands in Missouri?

Wetland managers don’t need to do anything special to accommodate the visiting masses of snow geese, especially since the geese tend to feed in surrounding agricultural fields. Managing for other waterfowl and shorebirds gives the geese what they need. Yet their presence can have an impact, varying by year and location.

At Loess Bluffs NWR, Welchert says the snow geese are “primarily using the refuge as a roost and loafing area.” The sheer number of geese, which can reach more than 1 million in the spring, can crowd ducks out of a pool, he says, but there doesn’t seem to be any direct competition for food.

In other places, such as Grand Pass CA, “High numbers of snow geese, especially in the fall, compete with other waterfowl for high energy foods and can quickly use up those resources,” says MDC Wildlife Biologist Robert Henry. “Likewise, large numbers of snow geese can knock down vegetation, making it difficult for hunters to hide during waterfowl season.”

MDC Wildlife Biologist John Marshall explains that snow geese sometimes cause nutrient loading. “The snow geese like to loaf on Cypress Lake, a 90-acre lake on Otter Slough, and the waste (bird poop) that builds up through the winter leads to summer algal blooms and fish die-offs when we have several days of overcast weather,” he says. “So, we often try to flush the lake with fresh well water in late summer to prevent fish kills.”

But snow geese also provide additional hunting opportunities and amazing wildlife viewing as well as food for predators. Coyotes “take off wounded or sick birds that are on the edge of the wetlands,” Welchert says. “And I’ve seen red-tailed hawks and northern harriers also take them … Eagles, when they’re here, feed on a variety of things and a lot of the time they’re feeding on snow geese.”

For snow geese, gathering in large flocks is a natural behavior — a survival strategy. Forbes explains that they are “overwhelming predators with their superabundance” and their “white coloration likely helps them blend in with patches of snow or ice, and possibly makes individual birds harder to target by predators when [the geese] are in large flocks.”

On winter wetlands, when an eagle flies overhead and the geese rise up in a moving sea of white, the chaos and commotion you see has a purpose. Those ten thousand goose voices you hear and the streams of geese you see crossing the sky are part of a story that spans two countries, connecting very different habitats. It’s a story that biologists are watching closely.

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This Issue's Staff

Magazine Manager - Stephanie Thurber
Editor - Angie Daly Morfeld
Associate Editor - Larry Archer
Photography Editor – Ben Nickelson
Staff Writer - Kristie Hilgedick
Staff Writer - Joe Jerek
Staff Writer – Dianne Van Dien
Designer - Marci Porter
Designer – Lyndsey Yarger
Photographer - Noppadol Paothong
Photographer - David Stonner
Circulation – Marcia Hale