Beaver, Muskrat & Nutria

BEAVER, MUSKRAT, & NUTRIA

Beaver, muskrat and nutria are all three considered wildlife nuisance because of being invasive species as they can cause much property damage, especially near shorelines.  A species is considered invasive if it meets these two criteria:

  1.  It is non-native to the ecosystem under consideration.
  2.  2.  Its introduction causes, or is likely to cause, economic or environmental harm or harm to human health.

This definition is derived from a Presidential Executive Order issued February 3, 1999.

All three of these mammals have caused quite a bit of property damage around Lake Harding.  So many members wrote to ask if I knew what could be causing numerous and large sink holes near their sea walls.  After reaching out to everyone and getting your feedback, I did some digging.  Using your information and that from numerous internet searches and information provided by employees of the Alabama Division of Wildlife and Freshwater Fisheries and the Georgia Department of Natural Resources, I have merged the data into one document for your convenience.

BEAVER

Beaver are one the largest rodents in the world and usually have one litter of kits of about 1 – 6 each spring.  Varying reports say adults can weigh from 40 – 55 pounds and be 3 – 4′ in length and live for about 24 years.

Beaver

They move with an ungainly waddle on land but are graceful in the water, where they use their large, webbed rear feet like swimming fins, and their paddle-shaped tails like rudders.  These attributes allow beavers to swim at speeds of up to five miles (eight kilometers) an hour. Their fur is naturally oily and waterproof.

They use powerful front teeth to cut trees and other plants that they use both for building and for food.  A beaver’s teeth grow continuously so that they will not be worn down by chewing on wood.  In fact, they can grow up to about 4′ in a year.  Their four incisors are composed of hard orange enamel on the front and a softer dentin on the back.  The chisel-like ends of incisors are maintained by their self-sharpening wear pattern. The enamel in a beaver’s incisors contains iron and is more resistant to acid than enamel in the teeth of other mammals.

beaver_teeth

In the absence of existing ponds, beavers must construct dams before building their lodges.  They are known for their natural trait of building dams on rivers and streams, and building their homes, known as ‘lodges’, in the resulting pond.

First they place vertical poles, and then fill between the poles with a crisscross of horizontally placed branches. They fill in the gaps between the branches with a combination of weeds and mud until the dam impounds sufficient water to surround the lodge.  Like many rodents, beavers construct nesting dens for shelter and for protection against predators. These may be burrows in a riverbank or the more familiar lodges built in the water or on the shore.  However, the basic interior design varies little and consists of one or more underwater entrances, a feeding area, a dry nest den, and a source of fresh air.  You can see from the diagram how this would undermine your shoreline.

Beaver Dam & Lodge

They are known for their alarm signal:  when startled or frightened, a swimming beaver will rapidly dive while forcefully slapping the water with its broad tail, audible over great distances above and below water. This serves as a warning to other beavers in the area.  Once a beaver has sounded the alarm, nearby beavers will dive and may not reemerge for some time.  They can stay underwater for 15 – 20 minutes.

A suggestion from one member to get rid of beavers is to take a piece of PVC pipe and drill holes in it.  You insert the pipe into the wall of the dam.  The beavers will try to repair the holes and once they realize they can’t, they will relocate.  You will also find trapping suggestions below.

MUSKRATS

The muskrat is classified as a rodent because of its four incisor teeth in the front of the mouth.  The two upper and two lower incisors overlap, allowing them to self-sharpen as they are used.  Folds of skin behind the incisors allow a submerged muskrat to cut vegetation without getting water into its mouth.  The size and weight of muskrats varies with regions, and the quality of food available.  Southern muskrats average around two pounds in weight, and weights of three and four pounds are common for muskrats in the Northern states.  Most adult muskrats attain a length of 22-25 inches, including the nearly hairless tail.

Muskrat.

The muskrat has relatively small front feet, with four major toes and small thumbs.  Hind feet are much larger, and partially webbed.  The tail of a muskrat is deeper than it is wide, and it tapers to a blunt point at the end. The species use their tails as an aid to swimming.

Muskrats are one of our most prolific species.  Adult muskrats can have up to five litters in a year’s time.  Muskrats in northern states seem to average about 2.5 litters a year. Muskrats in southern states often average 3 litters.  Litter sizes vary, and 5 or 6 kits per litter are common.  There is evidence that muskrat populations may be somewhat cyclic.  Muskrats produce fewer litters when populations are dense and more litters when populations are sparse.  The quality and abundance of food also affects the number of litters as well as litter sizes.

Muskrat Litter With Six Kits

Muskrats dig into dams, dikes, and other embankments to make dens.  Typically these dens have 2 feet or more of earth above them. However, when fluctuating water levels flood their initial den, muskrats burrow farther into the bank or dig new, higher den chambers close to the surface.  In such cases this can weaken the bank, or livestock and other large animals can pierce holes in the bank, starting the erosion process.

NUTRIA

Nutria are large, web-footed rodents that are more agile in the water than on land.  Their average life span is 8 – 10 years old and reports vary on their weight from being about 10 – 22 pounds.  The biology of the nutria species allows it to reproduce at rapid speed, making it an unwieldy animal to control if released into the wild.  A female nutria averages about five young per litter, but can birth as many as 13 at a time.  A female can breed again within two days after giving birth, meaning one nutria can have up to three litters per year.

nutria2

They live in burrows, or nests, never far from the water. Nutria may inhabit a riverbank or lakeshore, or dwell in the midst of wetlands. They are strong swimmers and can remain submerged for as long as five minutes.  Nutria constructs burrows in the banks of rivers, sloughs, and ponds, sometimes causing considerable erosion.  Burrows can weaken roadbeds, stream banks, dams, and dikes, which may collapse when the soil is saturated by rain or high water.  Rain action can wash out and enlarge collapsed burrows and compounds the damage.

Nutria Den Site

All of this information has been compiled from multiple sources.  Keep in mind the laws in Alabama and Georgia differ in some areas.  So, as you study this pay attention to what specifically applies to where you live.

Beaver, Muskrat & Nutria Size Differences

ALABAMA

According to Richard Tharpe, a Wildlife Biologist with the Alabama Division of Wildlife & Freshwater Fisheries, “All three species are considered furbearing animals in Alabama and have a regulated trapping season.  That being said beavers still have an open season year round and can be trapped or removed (by firearms where legal and safe during daylight hours).  I can’t give you the authority to discharge a firearm within the jurisdictional limits of a city, town, etc. that prohibits that activity.  Muskrats and Nutria don’t have a year round season so a permit to remove those species would be required.

For any wildlife which is causing property damage or is a ‘nuisance’; the Department can and, in most instances, will issue a Wildlife Control Permit.  This allows a landowner or their agent to remove the offending animal(s).  This permit originates out of a District Office and can be tailored to meet the needs of most situations.

I am not aware of nutria occurring on the east side of the state. We do have nutria moving up the western side of Alabama and have been documented as far North as Lock 17.  This information doesn’t conclusively mean you don’t have nutria, it would just be a surprise.  Their range continues to expand.  You could have muskrat in your area and we certainly have a wealth of problem causing beavers.  Nutria and muskrat normally eat aquatic vegetation but certainly may feed in the yard of a lakeside home.  Gnawing, cutting, debarking of trees and damage to seawalls should probably be attributed to the beaver.

I will assist you in any possible way.  My contact information follows.”

Sincerely,
Richard Tharp
Asst. Supervising Wildlife Biologist
Division of Wildlife & Freshwater Fisheries
Wildlife Section District IV
3520 Plaza Drive
Enterprise, AL 36330
334-347-1298 (Office)
334-347-9030 (fax)
334-432-0825 (cell)
Richard.tharp@dcnr.alabama.gov

Captain Chris Lewis with the Alabama Wildlife and Freshwater Fisheries, noted that, “beavers are one of our nuisance species listed as one the landowner can remove one that is causing damage without obtaining a permit.
Muskrat and nutria are listed as fur bearing animals and therefore having a trapping season.  Their season runs from about the first week in November until the end of February.  They can be trapped legally during that time and no license is required as long as it’s not being done for any commercial purpose.  Check one of the listed web sites for each year’s specific start date.”

Captain Chris Lewis
Alabama Wildlife and Freshwater Fisheries
Law Enforcement Section
Office 334-242-3467
Fax 334-353-1603
chris.lewis@dcnr.alabama.gov
Check out ‘Outdoor Alabama’ at:
www.outdooralabama.com

GEORGIA

As far as Georgia goes, Theron Menken, a Wildlife Biologist with the Georgia Department of Natural Resources Wildlife Resources Division sent the following information.

“Susan, as we discussed on the phone, you have a couple of options for controlling the beaver/muskrat populations.  You can either take on the capture of the animals yourselves or to sub it out to nuisance wildlife trappers.  The list of trappers can be found at www.georgiawildlife.com/NuisanceWildlife.  Beavers may be trapped anytime and there are no permits required.  Muskrats have a trapping season in GA (Dec. 1-Feb. 28) and can be trapped during this period (trapping license required).  I mentioned the possibility of continued trapping in the area to maintain lower populations of beaver and muskrat so damage to property would be minimized in the future.  I would contact the Georgia Trappers Association (GTA). They have a website, www.gatrappersassoc.com and a list of officers for the association with contact information for each.  I would probably start by calling the president of the association and go from there.

If you decide to tackle the problem yourselves, you will need a permit to remove muskrat.  Trapping is the most effective method for removing beaver and muskrat.  I would use 110 connibear traps placed in front of burrows along the lake bank for muskrat.  Larger size connibear traps (330) are available for beaver as well.

If anyone wants to give it a try, I can supply you with instructions on setting/using these traps and information on where to buy them.  You can also shoot them under the permit.  This would have to be restricted to shotguns with small size shot to minimize the chance of ricochet and hitting houses/people with a bullet.  The small size shot will not travel far when shot into water and the chance of shot deflecting to an unintended target is very low.

I will not authorize the use of any rifles on the lake due to safety concerns.  Let me know if the lake residents would like to take the project on themselves and I can even come out and demonstrate how to use the traps and where to set them if you like.

I included a fact sheet on beaver.  Drop me an email or give me a ring if you have any questions or need additional assistance.”

Theron

Theron Menken
Wildlife Biologist, Game Management
Wildlife Resources Division
(478) 825-6354 | M: (404) 780-9432

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Jeff Cody shared the following information.  “The newest pest we have here on the lake is called nutria.  They are a cross between a muskrat and a beaver.  This is a link to an article about controlling them as a pest.   http://icwdm.org/handbook/rodents/nutria.asp”  He also included a link to Georgia’s web site on the permits or lack of permits needed to control beaver, muskrat and nutria.   www.georgiawildlife.com/node/130

So, where can you get the traps mentioned earlier?  B W Capps & Son has two locations.  You can purchase a trap from them and the salesman can help you with instructions.

1210 Broad Street, Phenix City, AL  36867  Tel: 334-298-5502

5196 U S HWY 80 West, Opelika, AL  36804 Tel: 334-298-4212

Adam Cail suggests you add cut up apples or watermelon to the trap and hang on the side of your sea wall or floating dock about 3/4 of the way in the water with each side tied up.

As far as the information sent in to “shoot these pests” – that is something which might get you in trouble around here.  Georgia Power does not approve of this.  So, please, just use the traps.  The feedback on the traps has been extremely positive, with people saying they have caught as many as 40 in two – three weeks.

www.gatrappersassoc.com

www.georgiawildlife.com/node/130

www.georgiawildlife.com/NuisanceWildlife

http://icwdm.org/handbook/rodents/nutria.asp

www.outdooralabama.com

Compiled by Susan Webster Tompkins November 2014

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