Allegheny River Headwaters Watershed Conservation Plan

Allegheny River Headwaters Conservation Plan
Chapter 4. Biological Resources
pools present in forestlands to lay eggs and reproduce. Reptiles, especially snakes, keep pest populations
under control by consuming a variety of insects, mice, and voles.
Timber Rattlesnake
This venomous pit viper has developed a bad reputation without much just cause. The secretive and
docile timber rattlesnake, although quite poisonous, does not readily attack humans and is a rather
important species of the forest, especially for pest control. Timber rattlesnakes will hide, move away, or
warn humans with their signature rattle to avoid confrontation. They will only strike if surprised,
cornered, or touched. Maintaining a buffer of three feet around even the largest adults should prevent any
bites from occurring (PSU, 2003).
Timber rattlesnakes can be found in both black and yellow color phases throughout the Pennsylvania
and New York portions of the watershed. They have a large, flat, triangular head; it is shaped in such a
way due to the facial heat-sensing pits used for detecting prey. Rare specimens may grow up to 70 inches,
while the average snake is between 35 and 50 inches in length. They have a rattle at the end of their tail
that is used to warn intruders before defending themselves. Segments are added to the rattle each time the
snake sheds its skin, once or twice a year. However, the rattle is fragile and often breaks. Therefore,
counting a snake’s rattle segments is not an accurate measure of age (PA DCNR 3 ).
In both New York and Pennsylvania, timber rattlesnake populations are declining. They are
threatened within New York State and are a candidate species in Pennsylvania. Their decline is due
mostly to habitat loss and fragmentation, but their negative reputation with humans has also affected their
numbers. Snakes are often killed by those who encounter
them, simply because they feel that the snake poses a threat.
However, timber rattlesnakes are very beneficial species, and
their populations within the region and throughout their range
are necessary in maintaining healthy ecosystems. If a timber
rattlesnake becomes a nuisance or is taking up temporary
residence near buildings or homes, contact a local
conservation officer to have the snake removed (PA Fish and
Boat Commission [PFBC], 2004).
A timber rattlesnake (Source PNHP) Birds
Birds vary from small, pollinator hummingbirds to forest
dwelling warblers and robins. Larger birds of prey, such as eagles, hawks, and owls, hunt small rodents
and fish. Birds provide hours of enjoyment for birdwatchers, they control insect and rodent pests, and
pollinate wildflowers and trees.
Some birds common to the project area are wild turkey, ruffed grouse, woodcock, wood duck
cerulean warbler, mourning warblers, black-throated green warbler, saw-wheat owl, great horned owl,
barred owl, screech owl, red-tailed hawk, red-shouldered hawk, broad-winged hawk, Cooper’s hawk,
northern goshawk, pileated woodpecker, yellow-bellied sapsucker, and American bald eagle. Wood duck
populations, once nearly extirpated, made a recovery in the 20 th century, and are once again fairly
common (McNab & Avers, 1994).
Bald Eagle
Bald eagle populations were once ravaged by the secondary effects of excessive hunting and
pesticide pollution; but bald eagles are now on the rebound. In the 1980s, only three breeding pairs
remained in Pennsylvania; while as early as 1960, only one pair remained in New York. Reintroductions
of juveniles in both Pennsylvania and New York and protection through the Endangered Species Act led
to a steady increase in populations. As a result, the bald eagle’s status was downgraded from endangered
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