200,000 snow geese once flocked to this Pennsylvania lake, but climate change has caused the number to plummet

Patricia Exley of Valley Forge makes the hour-plus drive to Lancaster County each winter to witness a spectacle she believes everyone should experience — tens of thousands of snow geese that stop at Middle Creek Wildlife Management Area during their migration north.

“The experience was beautiful,” Exley said of her trip there on Sunday. “To think that so many of one species has agreed on something, anything, to stop here, and that we are lucky enough to be included in this moment. All of it is beautiful, the geese as well as the many people who are gasping in wonder as they take it in.”

Exley, a Realtor for Berkshire Hathaway, who posted video of the scene on Facebook, is one of tens of thousands of people who visit Middle Creek each year to see the spectacle or visit the Pennsylvania Game Commission’s live webcam.

But the peak number of snow geese arriving at Middle Creek’s lake has dropped precipitously in the five-year period from 2018 through 2023, according to Pennsylvania Game Commission records, raising the question: Why?

Up to 62,000 snow geese, the peak number so far this year, were counted Tuesday at the lake and ponds of Middle Creek, which is set in a valley of rolling hills and fields spread over 6,000 acres. Staff at Middle Creek count the geese twice a week, so it’s always possible a lot more, or a lot fewer, birds were present on the other days.

Though still a sizable number, Tuesday’s number was far below the record peak of nearly 200,000 that arrived during a count in 2018. Ever since, there’s been a steady decline in peak numbers. Of course, the migration season isn’t over and larger numbers of snow geese could arrive in coming weeks.

Lauren Ferreri, biological manager at Middle Creek, said in an interview in February that there is no threat to the overall number of snow geese, which are abundant in the U.S. And, she said, the number of birds that travel to the lake fluctuates yearly for multiple reasons.

“Their numbers are subject to pretty rapid change,” Ferreri said. “So I could report 15,000 one day, and then the next day, we could have 70,000.”

She said the populations are given to peaks and lulls that play out over years. However, climate change, she said, is likely a factor.

The birds’ migratory treks can take them 3,000 kilometers, or about 1,864 miles, as they seek to breed in the arctic and subarctic regions of North America in spring, then migrate south in the fall to spend the winter in inland and coastal areas, including Pennsylvania.

But warmer winters and less snow north of Pennsylvania mean the birds can travel closer to their ultimate destination rather than lounging in Pennsylvania waiting for a thaw.

“If you look at a snow coverage map northward, New York has very low snow coverage compared to normal, and the northern parts of the Finger Lakes are open,” Ferreri said. “So the birds that usually would stage at Middle Creek and wait for that snow cover to fade don’t have to wait anymore. They can keep going.”

Data show, for example, that the Finger Lakes region is warming, making it more inviting for birds to arrive earlier in the past.

Since 1893, five of the top 10 warmest winters in Ithaca, which lies at the base of Cayuga Lake, have occurred since 2000, according to data from the National Oceanic and Atmospheric Administration’s Regional Climate Centers. The current 2023-24 meteorological winter consisting of December, January and February is on track to end as fourth warmest at Ithaca.

Jessica Spaccio, a climatologist at the Northeast Regional Climate Center based at Cornell University, which is in Ithaca, sent The Inquirer data showing that the number of days with snow cover has declined there since the 1970s. It’s the same in other New York communities like Syracuse, Aurora, and Elmira, the data show.

“Winter temperatures have been increasing in New York, particularly when looking at the last 50 years,” Spaccio said. “There is year to year variability, with cold winters still occurring, but the trend is clearly warming. Temperatures can still be cold enough for snow, but we are seeing more warm-ups, causing the snow cover to melt or reduce between snow events. These trends are expected to continue as we continue to live in a warming world.”

Snow geese, with their black wing tips and pink beaks and feet, are among the most abundant water fowl species in the world and are widely hunted as game.

The greater snow geese that stop at Middle Creek can weigh up to seven pounds. And, as the name suggests, the greater snow goose is bigger than the lesser snow goose, which are not present at Middle Creek.

The greater snow goose can fly at speeds of 50 mph in flocks of more than 1,000. It mates for life and travels with its family. Armed with serrated beaks, snow geese are voracious feeders, ever in search of food. They start their migration moving north along what’s known as the Atlantic Flyway as ground cover and lake ice allows.

Ferreri explained that the birds are driven by their search for food and open water. So they flock to the 400-acre lake at Middle Creek when it’s not frozen and when there is not a lot of snow covering surrounding farmland or wetlands where they can feed on roots, plants and shoots.

The amount of open water and snow cover can strongly affect Middle Creek’s appeal for migrating snow geese in a given year. During extreme winters, they may bypass or stop only briefly at Middle Creek, as they fan out to other areas in search of food.

Likewise, warmer winters can have them heading north earlier. The trend is toward earlier springs in the Arctic, likely bringing more snow geese there sooner.

Agriculture practices also can scatter them away from Middle Creek, Ferreri said. For example, farmers planting winter wheat or other crops elsewhere can be a lure, because the birds can feed on surplus grain at industrial agricultural sites.

So predicting when, or how many, snow geese will arrive each year is difficult. They begin arriving at Middle Creek in early February as a migratory stop that can last through mid-March. Indeed, the peak for 2019 occurred on March 12 when 150,000 birds arrived.

“At the end of the day, it’s difficult to tell what the peaks will be, and when they will be,” Ferreri said. “Every year is different. "