The good news for squirrel hunters this fall is that squirrel populations are booming, according to the Pennsylvania Game Commission field officer reports.
That's due in part to last fall's mast production. Acorns were abundant, so squirrels entered last winter fat, sassy and healthy.
Fox and gray squirrels mate early, usually in January. About 45 days later in mid-March, three or four naked, blind, helpless pups are born. Young squirrels grow slowly. Eyes open at about four weeks, and pups finally leave the nest when about 10 to 12 weeks old in mid-June.
If the adults were well fed the previous fall, they produce a second litter in late August or September. This explains why squirrels are so abundant right now.
Last fall's bumper nut crop enabled squirrels to produce two litters this spring and summer.
This fall I'm seeing few acorns, so next year I expect most squirrels to bear just a single litter. In this way, squirrel populations are tied directly to fall mast production.
Though the diet and the reproductive biology of fox and gray squirrels are similar, there are striking differences between these two closely related species.
Gray squirrels are the more widespread species, common in dense deciduous forests, backyards, and city parks statewide. They are easily recognized by the white-tipped tail hairs that give the tail a "frosted" appearance.
Fox squirrels, almost twice the size of grays at about 2 pounds, are the largest tree squirrels in North America. The head is dark, the body brownish orange, and the bushy tail is dark, not frosted.
Fox squirrels prefer open woods with a sparse understory; gray squirrels favor heavier woods with a well-developed understory.
Though relatively common in Western Pennsylvania, fox squirrels are rare or absent from the central and northeastern parts of the state.
Fox squirrels are also behaviorally distinct from grays. They spend more time on the ground, move more slowly with a loping gait, and stop frequently to search for food and sniff the air for danger.
Scott Shalaway is a biologist and author. His other weekly Post-Gazette column " GETintoNATURE " is published in the GETout section, available only in the early Sunday edition sold Saturdays in stores. Shalaway can be reached at scottshalaway.googlepages.com and RD 5, Cameron, WV 26033.