Friday, September 9, 2011

Nature Guide: Signs of Fall

Since Hurricane Irene passed through, it suddenly feels like autumn. The leaves of oaks and maples haven't yet begun to change color, but there are other signs that fall is coming. Our Nature Guide Jon Latimer points out a few of them.

"After competing for mates and raising a family in spring and summer, robins and blackbirds are beginning to gather into flocks. Some of these flocks will migrate south, but others will spend winter in the deep woods. Smaller birds such as chickadees, titmice, nuthatches, and Downy and Hairy Woodpeckers are also gathering into mixed feeding groups that will forage together throughout winter.

"It won't be long before we begin to see Slate-colored Juncos. They travel in flocks of up to 30 individuals. If you watch a flock for a while, you will notice they have a definite social hierarchy, or pecking order. Adult males occupy the top rung of the social ladder, followed by young males, adult females and, lastly, young females. When they arrive at a feeder, dominant individuals eat first; lower-ranking juncos must wait their turn.

"There are also subtler signs that fall is on the way. For example, you may find a large number of spider webs around your home. This is because many spiders mate in fall, and female spiders spin webs to attract a male. Also, you may notice an abundance of acorns dropping off mature oak trees. Acorns are one of the most important food sources for wildlife. In fact, our squirrels are acting even crazier than usual as they rush to collect and store acorns for winter.

"Finally, one of the surest signs of fall is the appearance of the Woolly Bear Caterpillar. These fuzzy black and brown caterpillars wander around searching for a place to rest through winter, such as beneath loose tree bark or inside a log. Some people believe that the size of the brown middle section on this caterpillar predicts how severe the coming winter will be. The narrower the brown section, the harsher the weather. However, Woolly Bears with different sized sections commonly appear in the same year, so this folktale seems unlikely to be true."
Woolly Bear Caterpillar photo by IronChris