Appendix B: Control tips for common nuisance species in New York
Click here for "Wildlife Damage Management Fact Sheet Series--Snakes" from Cornell University
This account will focus on the four species that are often found near homes; the common garter snake, eastern milk snake, black rat snake, and northern
water snake. There are 17 species of snakes in New York. Eight of them are
statewide. Listed below are the species found throughout the state, and the
rarest species, because three of them receive special legal protection.
New York is home to two endangered snakes (Eastern massasauga and queen snake),
one threatened species (timber rattlesnake), and two species of special concern
(eastern hognose snake and eastern worm snake). Although the category, "species
of special concern" does not give any extra protection, it does show that
the population is low enough to worry biologists.
For more information and color photographs, see Cornell's wildlife damage
management fact sheet about snakes.
Nonvenomous snakes, usually docile:
- Common garter snake, Thamnophis sirtalis. Common
- Eastern milk snake, Lampropeltis t. tiiangulum. Common
- Northern brown snake, Storeria d. dekayi
- Smooth green snake, Liochlorophis vernalis
- Northern redbelly snake, Storeia o. occipitomaculata
- Eastern ribbon snake, Thamnophis sauritus
- Northern ringneck snake, Diadophis punctatus edwardsii
Found only in certain parts of the state—
- Black rat snake, Elaphe o. obsoleta (found only in scattered pockets,
upstate). Common near homes.
- Queen snake, Regina septemvittata. (rare, in scattered pockets
in western New York). Endangered.
- Eastern hognose snake, Heterdon platirhinos (coastal plains and
Hudson River Valley). Species of special concern.
- Eastern worm snake, Carphophis a. amoemus (coastal plains and
north to Albany county). Species of special concern.
- Shorthead garter snake, Thamnophis brachystoma (southern tier
Nonvenomous, aggressive (found statewide):
- Northern water snake, Nerodia s. sipedon. Common
around homes with nearby ponds.
Venomous, defensive (found only in certain parts of the state):
- Eastern massasauga, Sistrurus c. catenatus (rare, in Onondoga
and Genessee counties only). Endangered.
- Timber Rattlesnake, Crotalus horridus (rare, in lower Hudson Valley,
parts of western New York, and the southern Adirondacks). Threatened.
- Northern copperhead, Agkistrodon contortrix mokasen (lower Hudson
How to tell a nonvenomous snake from a venomous one in New York:
||Pupil: like a cat's eye, vertical
|No pit between the eye and nostril
||Pit between the eye and nostril
(the 3 venomous snakes in NY are all pit vipers)
|Shape of head variable, often slender
||Broad, triangular-shaped head
|Scales underneath the tail, toward the tip,
|Scales underneath the tail, toward the tip,
Black rat snake: Up to 4 1/2 feet long.
Garter snake: 2–4 1/2 feet, usually
Milk snake: Up to 4 1/2 feet long. Sometimes
confused for the copperhead.
Water snake: Up to 4 1/2 feet long.
Signs of their presence:
- Water snakes often sun themselves on boat docks.
- Milk snakes and black rat snakes are frequently found in barns.
- On cool days, you may find snakes (especially the black rat snake) resting
on top of the heating ducts in buildings heated with forced hot air.
- Sounds: Silent, except for the rattlesnake, which rattles, and the milk
snake, which may also vibrate its tail if annoyed.
- Scat: Elongated, whitish. The scat of a black rat snake may be large.
- Large shed skin (over 2 foot long): Probably from a black rat snake.
- Evidence of their feeding: Hard to identify, because they swallow their
- Garden and crop damage: None, because they are strictly carnivores.
- Building damage: None, because they use only existing holes and entryways,
and don't create others.
Carnivores. Black rat snakes eat mostly small rodents and birds. Garter snakes
eat mostly earthworms, but also slugs, amphibians, fish, crayfish, insects,
small birds, other snakes, and carrion. Milk snakes eat rodents and other snakes.
Water snakes eat mostly fish, also amphibians, insects, and crayfish. Other
snakes add spiders, bird eggs, and rabbits to the menu.
Typical activity patterns:
Social style: Solitary, but may hibernate with other snakes, even those of
Daily activity: Mostly diurnal. Milk snakes are usually nocturnal.
Hibernator? Yes. Snakes will often hibernate (usually from October/November
to March/April) in a large group that may include snakes of different species.
Migrates? No, but they do move to hibernating site.
Distribution in NY and the Northeast: The common garter snake, milk snake,
and water snake are common throughout New York. The black rat snake is only
found in certain spots in upstate New York. There is another species of garter
snake (the shorthead garter snake) that is common, but only in the southern
Black rat snake—woods, fields, rocky
hillsides, river bottoms. Often found in barns or other areas that are home
Garter snake—wide variety of moist areas,
from woodlands to marshes to fields.
Milk snake—usually seeks brushy or woody
cover in many of same habitats favored by black rat snake. Also often found
in barns or other areas that are home to rodents and other snakes.
Water snake—rivers, brooks, wet meadows,
ponds, and swamps, preferably still or slow-moving water, in areas with overhanging
branches and rocks (for cover and basking). Common near dams and bridges. Often
suns on boat docks.
Black rat, garter, and milk snakes will follow
their prey into barns and houses, usually in basements but sometimes attics.
That's especially true for the black rat snake, because it's an excellent climber.
Most snakes prefer sunny areas where rock or wood piles and other debris provide
cool, shaded hiding places. They move from sunny to shady areas to regulate
their body temperatures.
Territory and home range: Not generally territorial, but snakes are faithful
to den sites ("hibernacula") in their home range. They'll reuse these
sites from year to year, and are sometimes found in large numbers. This makes
them vulnerable to habitat destruction and persecution.
Pair bonding style: Polygamous.
Mating dates: Black rat: May–June.
Garter: first few warm days after emerging from hibernation, usually mid-March–May,
then mates again in the fall before entering hibernation. Milk snake: June.
Water snake mates in April–May and again in the early fall.
Egg-layers: Black rat and milk snakes lay
eggs in loose soil, decaying wood, or sawdust or manure piles. Black rat snakes
lay their eggs from May through early July. Milk snakes lay theirs in mid-June–July.
Live young: Garter and northern water snakes.
Birthing/eggs hatch dates: Garter snakes
give birth July-early September. Northern water snakes give birth in August-early
October. The eggs of the black rat snake hatch between July and September, those
of the milk snake from late August-October.
Clutch size: Black rat snake: average 14
(6–24). Garter: av. 14–40 (3–85). Milk snake: av. 13 (6–24).
Northern water snake: av. 20–40 (10–76).
Weaning dates: Young are able to fend for themselves at birth or upon hatching.
Common nuisance situations:
Time of year: Spring through fall.
Snakes don't damage buildings or eat crops. They only enter buildings through
existing holes, cracks or "doors" (such as an open window). Some people
are afraid of snakes. Others welcome them, because some snakes eat mice and
rats and help to control those pest populations. Remember, however, that if
a snake can get into a home, so can other creatures.
What are they doing?
- These snakes sometimes hibernate in buildings, especially the basements
of old houses with stone foundations. They usually enter houses through torn
screens, open basement windows, cracks in the foundation, or through gaps
next to pipe and cable entrances.
- They follow prey (mice, insects) into cellars, crawl spaces, attics, barns,
sheds, garages. They may also be found in wood piles and debris, in heavily
mulched gardens, and under shrubs, tarps or planks. They seek cool, damp,
- Their presence may frighten or annoy people. Several species, including
the garter snake, may emit a foul and musky smell when handled.
- Disease risks: salmonellosis (food poisoning).
- Injury risks: nonvenomous snakes have tiny teeth. They leave a faint, U-shaped
bite mark. Their bites rarely hurt much or cause problems, with the exception
of the northern water snake, which is known for its nasty bite. Few people
encounter New York's venomous snakes, and fewer still are bitten—and
even then, the bites are rarely fatal. A bite from one of New York's venomous
snakes (copperhead, massasauga, timber rattlesnake) will swell, hurt, and
turn black and blue. Children and the elderly are at greatest risk for a severe
reaction. If bitten, remain calm and get medical help. Do not use a commercial
snake bite kit; they tend to do more harm than good.
De-bunking myths about snakes:
- If bitten by a venomous snake, do NOT try to suck out the poison. Do not
slice the wound. Get medical help.
- Snakes don't dig. They can't make holes.
- The milk snake and northern water snake (both non-venomous) are often confused
for the copperhead or the water moccasin (both venomous).
Legal status in New York:
The black rat snake, garter snake, milk snake, and northern water snake are
unprotected. As are New York's other snakes, except:
Queen snake: Endangered.
Timber Rattlesnake: Threatened.
Remove their food sources:
- Grains, pet food, and bird seed will attract mice, insects, and other species,
which then attract snakes. Keep these foods in mouse- or insect-proof containers.
Exclude insects and mice from your buildings.
- Reduce the amount of mulch in your garden, around trees and shrubs (again,
this will discourage mice and other potential snake food).
Reduce their shelter:
- Mow closely around the building.
- Remove wood piles, junk, and piles of rocks.
- Don't plant right next to the foundation, because that provides cover for
snakes and many pests.
Prevent them from entering building:
- Seal all openings that are larger than 1/4" with mortar, expanding
foam, cooper mesh (Stuf-Fit®), 1/4" hardware cloth, or sheet metal.
- Fences may keep them out. Use 1/4" hardware cloth. The fence should
be 3 ft. high, buried 1 ft. deep, with the bottom edge bent outward into a
"L"-shaped shelf that sticks out at a 90° angle to prevent the
snakes from slipping under the fence. Fences are more likely to work well
around a small area. Otherwise, high maintenance needs may make this impractical,
because some snakes would be able to travel through chipmunk tunnels that
pass under a fence.
- Although snakes cannot create holes, they will use holes that were made
by rodents and other animals. To prevent the problem from happening again,
you may need to identify the maker of the holes and exclude them, too.
Direct capture methods and live traps for non-venomous snakes:
- Pick them up, wearing heavy leather gloves for protection. Support the
snake's entire body to keep it calm. Hold snakes behind the head, to keep
them from biting you.
- With care, snakes can also be captured with a "snake stick,"
which is a catchpole modified for snakes. A forked stick can also be used
(carefully!) to pin down a snake.
- They can be scooped into a garbage can using a scoop or shovel.
- To live trap water snakes, add a brick-sized piece of Styrofoam to a minnow
trap (so the trap will float, allowing the snake to surface for air). Bait
with about a half-dozen minnows. Attach a rope to the trap for easy retrieval,
then float it in near the shoreline.
- If the snakes can't be found, you can lure them to a spot where they can
be easily captured. Place piles of damp towels or burlap sacks on the floor,
near the walls. Cover the pile with a dry burlap bag to keep it moist. In
a few days, return to the pile during the middle of the day, when the snakes
are most likely to be there. Scoop up the pile with a large shovel, put it
into a large garbage can, and carry it outside.
- Several variations on the above technique: Use a board or a piece of plywood
instead of the pile of towels or burlap sacks. Place some decomposing grass
clippings on top of the board, which should be 1" off the ground. Dead
mice or mouse droppings placed underneath the board will help to attract snakes.
Check every few days. This technique works well with garter snakes and black
rat snakes, but is not as effective with water snakes.
- Create a reptile tube trap, based on a technique suggested by HSUS animal
capture consultant, Dave Pauli. Inside this trap, the temperature should be
just right for the snake—more appealing than the surrounding area. The
trap is a piece of thin-walled PVC tubing that's 2–3 ft. long. Drill
a few 1/8" air holes along the length of the tube. Cap one end. In cold
weather, place a disposable hand warmer, battery-operated electric sock, or
heating pad in the far end of the tube, along with some soft cotton rags.
If you have fresh rodent droppings, you may want to toss a few in there, too.
(In hot weather, substitute an ice pack or cold, wet rag for the heat source.)
Then drill a 1" hole into a cap and use it to cover the other end of
the tube. Although the snakes can leave the trap, they usually stay inside
because it's more comfortable for them. You can install a one- way valve by
affixing a 1 1/2" stiff plastic circle over the inside of the cap. The
snake can push its way in, but can't leave easily. (This trap also works with
other reptiles, such as lizards.)
- Glue boards designed for mice will also catch smaller snakes. You may be
able to release the snake unharmed by pouring a little bit of cooking oil
onto it. Some biologists believe the oil harms the snakes.
- Only experienced snake-handlers should capture venomous snakes. They're
often handled using a catchpole and then transferred into a sturdy container.
Using a one-way door to exclude snakes from a building:
- Technique developed by wildlife consultant William Bridgeland. Roll aluminum
insect screening into a tube, then attach it over the entry hole, which is
usually found in the foundation. Angle the tube up slightly, and flatten its
outer end a bit. Leave the tube in place for at least two weeks while snakes
are active (summer). Don't substitute another material for the insect screening.
Snakes may use scent to find their entry holes. Insect screening scatters
odors, which would make it harder for the snakes to locate the entry hole,
but other materials might retain their scent and direct the snakes back to
the opening. If they find the opening, they may be able to get back inside.
For NWCOs with a commercial pesticide applicator license:
- There's a repellent, Snake-A-Way, registered for use against rattlesnakes
in New York. Its effectiveness varies greatly depending on the species.
Preferred killing methods:
First, discuss the situation with your customer. Is it really necessary to
kill the snake? (And remember, is it legal?) Would removal and exclusion be
sufficient? If not:
- Shooting, using bird shot (target the head)
- Stunning and decapitation
For more information: