Squirrels Achin' for Acorns, Attack Pumpkins

By Ann Posegate

Wx and the City

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By John Mossesso Jr. Courtesy the National Biological Information Infrastructure digital image library.

Two days after Halloween, while in Arlington, I happened to see a squirrel devour a front-porch pumpkin. At first, I thought it was cute. But I quickly realized that I'd never seen this before, and wondered why the squirrel was so hungry. Other nearby porch pumpkins had bite marks and holes in them as well.

A few weeks later, I noticed this comment by gpmega in response to our Winter Outlook:

"Ok, this may be a bit silly, but... All over my Arlington neighborhood, and in other areas around DC (according to a very unscientific survey of my coworkers), the squirrels ate large portions of the jack-o-lanterns. This is the first time I've ever seen such behavior. Are they fattening up for a severe winter, perhaps???"

Keep reading for more on the strange behavior of area squirrels and the role weather might play...

According to folklore, "squirrels gathering nuts in a flurry will cause snow to gather in a hurry." Does this apply to pumpkins too? Or is the lack of acorns the work of thousands of squirrels across the region tricking us with swift acorn-gathering in the middle of the night? While there is scientific evidence of squirrels' caching behavior (storing nuts for winter), little is known about a direct relationship to the severity of the coming winter.

This fall was a fateful season for Jack O' Lanterns and pumpkins across the region. According to a recent Washington Post article, squirrels in Northern Virginia, parts of Maryland and the District have been chowing down on pumpkins, bird seed and garbage scraps because there are few to no acorns to be found. It seems that oak trees in the D.C. area and other places did not produce an acorn crop this year, and one culprit might be weather.

Being a nut-bearing tree, an oak's life cycle is directly tied to seasons, and its productivity is dependent on weather. For example, white oak tree flowers are pollinated in the spring; acorns grow and mature throughout the summer; and acorns fall to the ground in autumn. According to the U.S. Forest Service, anthers (the flower parts that produce pollen) on white oak flowers open and close with changes in humidity. Also, a very rainy spring can damage flowers, delay pollen production or reduce pollen dispersal. The most productive white oak acorn seasons are those with a stretch of 10 warm days followed by a few weeks of cool days; whereas, the least productive are those in which cool temperatures precede warm.

The weather could be one factor in the lack of acorn crop this year. As you may recall, spring of 2008 was wet, with a May rainfall total of 10.66 inches -- the second wettest on record. The rainy spring was preceded by several months of drought.

Even though a single mature white oak can produce 10,000 acorns annually, it will also go through years of little to no acorn production depending on external conditions. One year without acorns shouldn't cause us too much worry. However, it is definitely something to monitor; if the lack of acorn crop becomes a trend, this behavior could be an indication of other environmental and climatic factors at play.

Want to help monitor the seasonal life-cycle events of plants or animals? Check out the USA National Phenology Network's citizen science projects, where you can volunteer to help monitor changes in plant and animal life cycles and behavior.

For now, watch out for hungry squirrels...