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Impact of snow on birds and insects

A. Drew Smith
Fort Smith Times Record

In Arkansas, the rare snow has brought out bird watchers and raises the question of the impact on insects.

Dr. Ragupathy Kannan, an ornithologist with the University of Arkansas-Fort Smith, noted the increase in the number of birds coming to bird feeders.

When it snows, birds are not able to find their natural food sources as easily so they turn to bird feeders as easier sources of food.

According to Kannan, Juncos are some of the most popular birds to make their appearance in the snow.

During the recent snowstorm, the birds didn't seem to care who came to their "buffet." Here there are a dark-eyed Junco, a Northern cardinal and a goldfinch (in its winter garb) all sharing space at the feeder.

"Juncos are sometimes called snowbirds since they show up with the first snow." said Kannan.

Kannan also pointed out that Juncos, American Robins, Northern Cardinals, Carolina Chickadees, and Tufted Titmice enjoy black-oil sunflower seeds. These birds are native to Arkansas and would be seen by birdwatchers in the River Valley.

“These sunflower seeds are full of fats and carbs that keep the birds warm, and Blue Jays are always attracted to shelled peanuts - unsalted, please!” said Kannan.

Other birds, including owls, come out in the snow. According to Kannan, owls fly around even in the daytime and are most often seen in open fields like the ones found in Charleston and Fort Chaffee.

A sparrow peaks out from behind a bird feeder on February 9, 2021.
A male cardinal seeks food from a bird feeder on Feb. 17, 2021 in Fort Smith

Bugs in the snow

Insects, on the other hand, sometimes benefit from the snow.

Nature adapts to the climate and this strange winter storm had the potential to damage the lifecycle of several different animals, this snowfall was the opposite of dangerous to insect life.

Kelly Loftin, extension entomologist for the University of Arkansas System Division of Agriculture, also said not to look for the cold to have reduced fly or tick numbers,

In general, Loftin said that “insects that are endemic to our region have evolved various mechanisms to survive cold winters.” However, invasives that originate from warmer climates don’t have those means for survival.

Fire ants and freezing weather

“Imported fire ants are a good example of an exotic species that can be adversely impacted by extreme cold temperatures,” he said. “This pest ant has expanded its range about as far north as it can under normal winter conditions. And north Arkansas is the northern limit of its range.

“Although imported fire ants are native to South America, they survive most Arkansas winters,” Loftin said. “However sustained cold can cause a temporary population reduction.”

He said that a decade ago, when parts of the state sustained seven days below freezing,  “Arkansas’ fire ant population experienced a 70 percent reduction in the number of fire ant colonies.” he said. 

But you can’t keep fire ants down for long. 

“About 1.5 years later, fire ants returned to the prior population level,” he said. “Fire ant colonies associated with sidewalks, parking lots, foundations, and other areas tend to survive simply because these structures serve as heat sumps thus preventing colonies from freezing.”

Ticks

Ticks are pretty good at finding protected places to ride out the freezing weather, UA Division of Agriculture writer Mary Hightower points out.

“Species such as the American dog tick and lone star tick survive the winter by seeking shelter as adults and nymphs in the leaf litter,” Loftin said. “Other species such as the winter tick are attached to a warm host during the cold winter.”

“If you look at the geographical range of the American dog tick, black-legged tick and winter tick, all three survive up to the Canadian border and beyond,” he said. “Even the lone star tick survives up to the Great Lakes region.”

Loftin said temperatures will influence when ticks become active. 

“For example, if we have a warm spring, we will see active ticks in March or April,” he said. “And during warm spells during winter months you may see an occasional active lone star or American dog tick in January or February. Likewise if temperature remain cold in the spring, ticks will not become active as early.”

Flies

Don't count on a week of freezing temperatures to knock out flies, Hightower adds.

“The house fly range is worldwide including the Arctic, so obviously we wouldn’t expect to see much winter mortality,” Lofton said, adding that “our most important livestock flies have different mechanisms to survive cold winters. 

House flies and horn flies of cattle survive cold temperatures as larva or pupae under manure piles and other protected breeding material.

The face fly is a pest with a different overwintering strategy as a hibernating adult. Introduced from Europe into Nova Scotia, Canada, about 1950, face flies hibernate in church steeples, attics, barns, and other protected areas. 

“I routinely see hibernating face flies on warm days in manmade structures,” Loftin said. “Many times they are numerous enough to become household pests.”

Row crop pests

The effects of the deep freeze are uncertain, said Ben Thrash, extension entomologist for the Division of Agriculture. 

“We can safely say the redbanded stink bugs and southern green stink bugs will be knocked back for the next several years,” he said. “I think many our native species will be relatively unaffected.”

However, the cold’s effects on insects that migrate to Arkansas isn’t known yet. 

“Insects like corn earworm and fall armyworms do overwinter here Arkansas, the cold should have killed them here, but many of our most damaging corn earworm populations migrate from places like the lower Rio Grande Valley in Texas and south Louisiana,” Thrash said. “I’d bet we will still see these insects, but they may just be delayed in getting here.”

“I would like to put some data together sometime to see if there are any trends I can pick out with weather and certain species,” he said. “Other things like how wet our spring is can also have major effects on our insect populations by promoting weed growth.”

Thrash recalled something former Arkansas soybean breeder Chuck Caviness said when asked to predict a field’s soybean field. Caviness declared “Only fools and newcomers try to predict soybean yield, and I’m neither.”

Thrash said, “I’m beginning to feel the same way about predicting insect numbers.”

According to professors from Washington State University and the University of Idaho in a 2019 article, large amounts of snow actually lend to the ground being insulated and not freezing as deep as without snow.

Since February is still during the winter hibernation cycle for insects, the impact on them is low even though this is an unexpected snowstorm with the highest amount of snow in several years.

According to Ryan Pankau of the University of Illinois, bugs bury their larvae deep enough to avoid the level of ground freeze. Since Arkansas experiences mild winters, insects would usually bury their larvae deeper than places that experience regular snowfall where the ground does not freeze as deep.