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Feral Colony Management
The Humane Solution to Cat Overpopulation

The efforts of animal shelters to place all the adoptable cats they receive are thwarted by the vast number of kittens brought to them each year.  These kittens are not the litters of house cats -- the majority of them are neutered at an early age.  Rather most are the offspring of feral cats -- often the second cousins of lost or abandoned house cats -- that have adapted to outdoor life, colonizing around various food sources -- urban dumpsters, rural fields -- wherever food scraps and/or rodents are plentiful.

They are wary of people and frequently go unnoticed until their numbers grow or they deliver a litter in someone's garage or under their porch.  Then a property owner typically traps them and takes them to a shelter where the feral adults are put down and, if possible, the kittens are socialized and put up for adoption -- otherwise, they too are euthanized.

This practice eliminates the visible cats from the territory, but does not solve the problem -- shortly after, other roaming strays will move in and take over the freed-up food source, begin reproducing, and soon fill up the territory again.  Because of this phenomenon, we know we can't eliminate feral cats altogether -- no matter how many cats we remove -- but, we can greatly reduce their numbers -- through the practice of managed trap-neuter-return (TNR).  Leave the cats where they are (to guard their food source from roaming cats) but sterilize them to stop the reproduction. 

Through this practice, the very cats that are at the root of the overpopulation problem, become the solution to it!

As a bonus, managed TNR strengthens the bond between cats and caregivers and improves the quality of life for the cats -- now sterilized, they live longer and healthier lives -- toms no longer fighting and females no longer wasting from repeated pregnancies.

Understanding Feral Cat Colonies

There are several thousand feral cats living in greater Washtenaw County clustered in colonies of 2-50 cats.  They colonize around a food supply -- in urban areas, the contents of, and the rodents attracted by, apartment, restaurant, and commercial dumpsters -- in suburban areas, rodents and food put out by people in rural areas, rodents attracted to feed put out for farm animals.

Colony Size

The size and density of the colonies is determined by the size and density of their food supplies.  Each colony anchors around a predominant food source.  The more bountiful the food source, the larger the colony.  And the denser the food sources, the denser the colonies.  A large apartment complex, with several dumpster locations, will likely have several separate and distinct colonies, as will a row of fast food restaurants.

Territory Size

The territory of each colony is well defined (by the cats) who will defend their territory from roaming cats.  The territory is bounded only by other colonies.  In areas dense with food sources, the territories are quite small -- but in rural areas, they can be very large.  The colony territories are separated by neutral territory.  Females seldom leave home, but the males roam over large areas and these neutral territories are their paths through other colonies.  In areas dense with colonies, these pathways are narrow and may even be time-shared -- Colony A gets to use it only in the morning, and Colony B only in the afternoon.

Sound feral cat management recognizes these behaviors and takes advantage of them.  We know we can't eliminate the colonies.  Removal or eradication of them just creates a void that stragglers from other colonies will quickly fill, reproduce and grow back to the size the food source will support.  The practical answer, and the only humane answer, is TNR.  Leave the cats where they are -- but stop their reproduction.

Establishing A Managed Colony

Importance of Colony Management

At first glance, the situation may look hopeless.  Given the large number of feral cats, what can be accomplished by sterilizing scattered colonies (where the property owners allow it) -- especially if we then feed them to keep them healthy? Isn't that just increasing the food supply -- allowing more and bigger colonies? No -- because the colonies exist, their territories are defined.  Adding a new food station into their territory feeds only that colony.  The former food source becomes less used -- but still fully protected from other cats.

Each colony we TNR represents one geographic segment -- one plot of land -- that protected.  It stands on its own -- irrespective of what's happening in the surrounding colonies -- so long as we continue to monitor and manage it.  And, linked together, these managed colonies will eventually end the community's reliance on homeless cat euthanasia -- by replacing it with a grass-roots network of kitten-free zones where no new cats are born.

Locating Feeding Stations

So the first step in managing a colony is determining where to put the feeding station -- where best to place the daily meals for the cats.  This is subject to several constraints:

  • It needs to be where the cats can safely and comfortably access it -- in an area of minimal human activity (at least in the times surrounding your selected feeding time) and out of clear public view.
  • It needs to be where you can conveniently access it -- even in the winter months with heavy snow.
  • It needs to be where the property owner wants it (or at least where they will allow it).
  • It needs to be in the colony's territory -- if there are many colonies close together this may require observing the cats for a few days to see where they eat, rest and sleep.  Or experiment -- pick a spot that the other constraints allow and see if it draws the cats you first saw and expected to draw.  If it draws none or just an occasional random cat, it's probably in neutral territory -- between colonies -- and should be moved.  If it draws different cats than you expected, it's probably in another colony's territory and you'll need to decide whether you want to manage that colony in addition to the one you initially targeted.
Generally, the ideal spot is as near their current predominant food source as the constraints allow -- but if a dumpster, far enough away to be shielded from the dumpster's normal daytime human activities (pickup and disposal).  If you place the feeding station away from where the cats are already eating, do it gradually -- move it a few feet each feeding until you have it in the desired location.

Managing The Colony

Daily Feeding

With the feeding station located, start feeding -- once a day -- dry and/or wet cat food and fresh water.  Pick a time that's convenient for you -- early morning, mid-day, late afternoon.  Pick a time in the daylight -- don't forget that those hours are shorter in the winter.  Food put out after dark is more likely to draw other wildlife (unless you remain in the area while the cats are eating -- which you might be reluctant to do on cold winter nights.  Be consistent -- same time, same place, every day.  Find someone who'll do it for you on days you can't make it.  Soon you'll have seen all the females in the colony.  Some of the males might be out roaming so it may be several weeks before you've seen all of them.  If there are several cats, you may wish to keep notes to help you identify them.


Once you have a feeding routine in place so the cats come at the same time each day to eat, you can start the most important part of managing a colony -- getting the cats spayed and neutered.  Be sure you have a willing vet lined up before starting -- and try to trap in coordination with the vet's schedule.  Although it doesn't make much difference (as your goal is to fix all of them), if you have a choice, start with the females.  But, if you have a nursing female, it's probably best to wait to sterilize her until the kittens come out of hiding and you see them eating solid food.  If you find a pregnant female, we recommend spaying as soon as possible -- sad as that may be.

This will seem to be a daunting task but once you start the process it'll be over sooner than you think.  Once the colony is sterilized the cats become more friendly and will no longer engage in fighting, spraying and yowling.  The resulting colony will be more mellow and more rewarding to take care of.



You'll need one or more live traps.  You can buy them from local pet stores, hardware stores -- or online from a company like Tomahawk (Model 608 for cats, Model 605 for kittens).  You can also rent traps from general rental businesses and some vet clinics.  Be sure your traps are clean for each use.  Wash them with hot soapy water and rinse well, disinfect with a diluted bleach spray (1 part bleach to 32 parts water).  (Diagram courtesy of Best Friends Animal Society.)

Trap Bait

Bait the trap with a generous dollop of pungent food -- wet cat food, sardines, oil-based tuna, canned mackerel, etc.  Put it on a small paper plate, plastic dish, peanut butter lid -- anything that doesn't have sharp edges and can't break.  Then put it as far back in the trap as possible -- behind the trip plate but inaccessible from the outside.  You may want to trail some bits of the food out to the opening to help lure the cat in.  Cover all but the opening with an old towel, blanket or sheet -- this gives added camouflage and will help calm the cat after it's caught.

Trapping Process

Plan to trap at your regular feeding time.  You may wish to skip feeding the previous day so they'll be extra hungry.  Place the trap near the feeding station.  Under a bush or in a hedge is preferable to out in the open.  Make sure the rear (sliding) door is latched.  Line the bottom of the trap with newspaper just covering the trip plate -- the cats may be hesitant to walk on wire mesh.  If you're using multiple traps, place them where they'll be visually isolated from each other.

Wait quietly in an area where you can observe, yet far enough away that the cats aren't wary.  Do not leave the trap unattended -- other animals can be a danger to the trapped cat and the cat can be a danger to people who may not realize that it's feral.  After trapping the cat, take it immediately to the vet to be sterilized.  Leave the covering on the trap -- besides helping calm the cat, it helps protect you from the cat.  Carry the trap only by the top handle and carry it safely away from your body.

Over-Night Care

If you have to keep the cat overnight, put it in a protected area such as your basement or garage.  Keep the trap covered and check it periodically -- but don't stick your fingers in or allow children or pets nearby.  Lift it up from the floor on 2x4s with newspaper underneath so they can eliminate with minimal soiling.  Do not feed for 12 hours before surgery.

Long-Term Care

If the cat is in the live trap for more than a day, -- not recommended -- you'll need to give the cat food and water.  Be careful! The cat is wild and it's scared.  It will try to escape if given any chance and may strike out at you at any moment.

Use the rear (sliding) door for access.  Use a trap divider (if available) or a blunt stick to encourage the cat to the opposite end of the trap.  (Don't use anything sharp or splintered that might injure the cat.) Then open the sliding door just enough (no more than an inch) to fish out the bait dish (using the stick -- not your fingers).  Clean and refill it with cat food and slide it back in.  Slide in another shallow dish for water.  Fill the dish with water from outside the trap using a watering can, an old turkey baster, etc.  You'll need to repeat this a few times until the day of surgery but remember to withhold food for 12 hours before surgery.

Special Situation Trapping

The following are some special situations you may encounter:

  • Stray.  The cat you trapped may turn out to be "stray", i.e,, a house cat that's been lost or abandoned but not feral.  Stray cats will usually meow, move around and make eye contact from the trap, while ferals will be either very aggressive or remain absolutely still and quiet in the back of the trap.  With a stray, we recommend that you try to find the cat's guardian -- and, if you can't, then leave the cat in the colony while you try to find a permanent adoptive home.  See our handout, "Stray Cat Tips", on our web site.
  • Hard To Catch.  For cats that are especially trap wary, you may need to condition them to it for a few days.  Move the trap closer to the feeding station and tie the door open with string.  Put some food outside the trap near the open door.  Each time you feed, move the food nearer, then into the trap.  When the cats are accustomed to eating in the trap, remove the tie.  If this isn't working, try other foods -- a catnip or valerian broth (very pungent), warm baby food.  If nothing works, try waiting a week or two before resuming trapping.  A short break can reduce the cats' fear of the trap.
  • Trapping Kittens.  If you have young kittens in your colony, we recommend trapping them when they are 4-10 weeks of age to socialize and adopt out as pets person-to-person.  See our handout, "Kitten Care & Socialization", on our web site.  If this is not possible, or if the kittens are older, we recommend leaving them in the colony and sterilizing them -- typically at 3-4 months of age.  To trap kittens, use a kitten trap or add weights to the adult trap's trip plate.
  • Trapping Mother Cats.  To trap an evasive mother, first catch her kittens and put them in a pet carrier.  Then set a trap and place the carrier behind it with the door facing the back of the trap).  The food and the sound of the kittens will lure her into the trap.
  • Selective Trapping.  After most of the cats have already been trapped, you may need to control when the trap door closes to catch the right cat.  On the Tomahawk trap, a small L-shaped pin holds the spring-loaded door open -- a mechanical linkage from the trip plate pulls the pin back, releasing the door.  To release it manually, wedge something under the trip plate to prevent it from releasing the door (a scrap of wood, bulk eraser, etc.).  Tie a loop in the end of a string and, through the top of the trap, slip it over the L-shaped pin.  From anywhere behind the trap, gentle tug on the string will release the door.  (For best leverage, the string should be in the crook of the L and pull back straight toward you.) Put extra food in the trap as many cats may go in and out before the right one does.

Veterinary Options


Leave the cats in the traps when you take them to the vet.  This alerts them the cats are feral and they can anesthetize them through it without having to handle the cats while they're awake.  They should put them back in the traps after surgery so you can safely release them.  If you are a participant in our TNR Assistance Program, plan your appointments when you first receive your vouchers -- they expire in 30 days and vets cannot always take a cat immediately.  Explain you are bringing in feral cats and that there is a chance you may have to cancel if you don't catch one.  Most vets will understand but schedule only one or two cats at a time so they don't lose their whole surgery schedule if you are unsuccessful at trapping.

In addition to spaying or neutering, our vouchers cover the full cost of the following services: ear-tipping, vaccinations for rabies and FVRCP, one dose of Revolution (for parasite treatment).  The bill for this work is sent directly to us for payment.

If you authorize work beyond our scope, you will need to pay for it -- and the vet should quote the work before doing it.  Below are the most common procedures done when a cat is sterilized -- including the ones we cover.  If you're not a participant in our Plan, this list gives you information you'll need to decide which services you want performed.

Distemper & Upper Respiratory Vaccinations

Most pet cats are vaccinated for FRTC or FVRCP (a combination vaccine that covers feline distemper (panleukopenia) and upper respiratory diseases (URI).  Arguments against vaccinating feral cats are that the protection of one injection is unknown -- and it's unlikely you'll bring the cats back for booster shots.  Once a feral cat is a year old, it has probably been exposed to these viruses and may have built up an immunity.  On balance we recommend the cats be vaccinated.

Note: If you bring in a cat with signs of a URI for sterilization, the vet may send him home with antibiotics to bring back when the cat is healthy.  URI's are like human colds -- viral and untreatable -- but, they can develop bacterial infections at the same time which antibiotics treat.  If you see green or yellow goop coming out of the nose or eyes of your cat, it's good to get treatment for the bacterial infection.  Cats vaccinated for URIs will still get them, but generally will not get as sick from them.

Rabies Vaccination

Vets commonly vaccinate for rabies.  An argument against it is that rabies in cats is extremely rare and they are not a reservoir species for it.  However rare, it is a public health risk and will affect the public's perception of your cats and we strongly recommend getting the vaccination.

Parasite Treatments

Vets treat parasites they find or suspect (ear mites, fleas, tapeworms, hookworms, roundworms).  Arguments against this on feral cats are that, while the parasites are bothersome, they are a serious threat only to the very young -- and that the cats will reacquire the same parasites when returned -- as the medications work for only a month or so.  We recommend that cats be treated for visible parasites -- and, recommend that the caregiver provide ongoing treatment.  The vet can recommend medications that can be mixed in food to avoid handling the cats.

Pre-Surgery Blood Work

Veterinary practice recommends taking blood work prior to surgery to ensure there are no hidden health issues that will make the cat a poor risk.  And, we support this practice as a "general" rule.  However, feral cats tend to be younger cats and the blood work, although important, is not as needed as it would be with an ill cat having other types of surgery.

Post-Spay/Neuter Antibiotic

This is a procedure that vets commonly do not do -- that you may wish to consider adding.  Cats are sterilized in sterile settings -- no antibiotics are needed.  However, these cats are not being returned to an indoor home.  The colony's environment provides greater opportunity for infection.  Alternatives to the injection include keeping the cats confined while their incision heals -- or watching closely for signs of infection at feeding time and re-trapping the cat if necessary.

Post-Surgery Pain Medication

Some vets recommend pain medication for your newly-sterilized cats -- or give them an injection of it.  This may be good for some cats, but not generally needed -- during surgery they're under anesthesia and do not suffer from pain.  You may want medication if you are worried about post-surgical pain -- or may wait to see signs of pain first.

First Aid

While the cat is anesthetized, the vet may want to treat other injuries -- bites, cuts, scratches, even bad teeth.  Here you have a decision to make as there is no absolute answer.  What treatments you provide depend on how seriously ill or injured the cat is, how able you are to provide follow-up treatment, and how much money you are able to spend.


Leaving the cat overnight for observation after surgery may be helpful -- especially in the winter -- if you have no place to keep the cat yourself and if you can afford the boarding fee.


All feral cats being sterilized should have their left ear tipped at the same time.  This is a symbol used internationally to identify cats that are members of managed feral cat colonies.  It also helps you to spot the still-unneutered cats (and newcomers) that still need to be done.

Viral Testing

Vets test for Feline Leukemia (FeLV) and Feline Immunodeficiency Virus (FIV).  These viruses cannot be transferred to humans and less than 4% of all cats have either.  Sterilization stops the behaviors most responsible for the transfer -- biting, mating and birthing.  We don't test but respect others that do -- provided they can handle the consequences.

Returning Cats To Their Colony

Generally you can release the cats as soon as they are out of the effects of the anesthesia -- alert with a normal body temperature.

Some vets recommend holding them -- especially females -- a day or two to be sure no complications develop from the surgery.  If you can, it's best to do so, but if it is not feasible, don't worry.

When holding them after surgery, follow the same procedure outlined earlier for holding them before surgery -- protected area, trap covered, free of children and pets and carefully providing food and water.  You may wish to add something soft and absorbent -- like an old towel -- for the cat to lay on -- crack open the sliding door and push it in with the stick (not your fingers).  When the holding time is up and the cat is fully alert with no complications, return the cat to where you first trapped him (still in the trap, the trap still covered).  Hold the trap with the door facing away from you and open the door.  The cat will likely bolt out immediately -- it's scared and finally given a chance to "escape".

If the cat doesn't leave the trap, tilt the back of the trap up slightly and tap on it -- or prop open or remove the door and leave it for awhile.

Occasionally a cat may disappear for a day or two after being returned -- but don't worry -- they will eventually return for their scheduled feedings.

Providing Dry Shelter

Cats need shelter from wind and wet.  Cold is not a problem -- outdoor cats grow a heavy winter coat and will naturally huddle together (left) to share body warmth when it's especially cold.  (Cats were primarily outdoor animals before kitty litter came along in the 1950s.) But they do need protection from the elements -- something to crawl into or under to stay dry.  This may be something that already exists -- a porch, a utility shed, an unused doghouse.

Or you can build something -- Alley Cat Allies' web site has plans for a marvelous shelter (see snow photo below) that comfortably shields six or more cats.  Or jury-rig something -- a plastic bucket, deep tray or garbage can -- turned upside down with an access hole cut in it (and anchored to the ground so it doesn't blow away) -- or a wood or perforated plastic crate with a garbage bag tied over the top to keep the inside dry.

What's important is to make sure the cats have something to shield them from rain and snow and break the wind -- and in the winter months, that "something" is as important to their survival as their food.

Monitoring The Colony

All that remains is to keep a close eye on your cats at feeding time to spot newcomers or ones you may have missed.  Get them sterilized quickly as they are (or have become) part of your colony.  Over time, some or all will become friendly to you -- you've become their "Mom-cat".  Don't be tempted to take one home with you -- or bring them inside -- or attempt to adopt them out.  They will not exhibit the same friendliness to others.  And they will not appreciate being cooped up.  Their territory is their home -- and you've made it extra special for them simply by providing food, water and shelter.

Transfer Of Care

If for any reason you are unable to continue the care of the colony, make every attempt possible to find someone close by to pick up their management.  Fortunately, since the cats are now all sterilized, the number of cats present will be much less -- and may have dropped more through attrition over the years.

If no one is available to care for them, you have two other possible choices: one is to move them with you to your new home and continue their management and the other is to find someone with a farm or large yard that will take the cats to manage.

Neither of these choices is optimal and, will not work, unless you move as many of the colony as possible to the same new location and confine them in a large dog crate or safe room -- that they cannot get out of -- for 21 days.

The territorial nature of cats dictates that if you move them, they will try to go back to their old home.  The confinement keeps them in the new location long enough for them to adapt to it and think of it as their home.

Safety Precautions With Feral Cats

Much of this material has been extracted from an article appearing in the November, 1999 issue of Catnip, a publication of Tufts University School of Medicine.  The article was entitled, "Wildcats in Your Backyard", authored by Jennifer Hunter.

Don't worry too much about feral cats attacking you.  They're terrified of you and will only bite or scratch if handled or provoked.  The greater threat is disease.  If you're handling the cats, wash extremely well before handling your own cats.  It may sound like overkill, but you may even want to change your clothes.  Cats can sneeze on your clothing and disease may be transferred that way.  Remember, too, that it's not just your pets at risk -- some diseases can be passed from animal to humans.

Territory Issues

Most ferals won't even allow themselves to be touched, much less settle into your home as a house cat.  If you try to take one in, remember that the cat is used to having total freedom.  His territory may have extended for a couple of blocks.  Now he's limited to half an apartment.  This can make for some nasty fights with other cats present.  Generally, introducing a feral cat to your home cat population is a bad idea.

Bites and Scratches

In making contact, let the cat set the pace or you may get scratched or bitten.  Wear padded gloves and long sleeves as a precaution.  Feral cats can inflict some serious damage.  If a cat bite breaks the skin, wash it well and go immediately to a doctor.  Cats' nails and teeth harbor bacteria and the risk of infection is very high.  If you get scratched, wash out the wound and keep an eye out for infection and fever.  Infected cat scratches can cause lymph node enlargement, fever, fatigue, sore throat and headaches.  If you're scratched, immediately wash the wound.  Contact your doctor if any symptoms occur.


Rabies, although feared, is relatively rare among humans.  Still, you might want to get a pre-exposure vaccination and have all ferals vaccinated.  Any cat who bites a human must be quarantined and examined.


Felines with this upper respiratory infection can pass it to humans in the form of conjunctivitis (pinkeye).  Don't touch your eyes after contact with feral cats.

Fleas and Ticks

Feral cats may carry ticks infected with Lyme disease, which could transfer to humans and other animals.  Check your whole body carefully after spending time in a feral cat area, especially if tall grass is present.  If you find a tick, send it to a testing center to determine if it's a carrier.  You may want to spray the area for fleas and other pests.


Ringworm is actually a fungus and can be transferred to both humans and other animals.  It makes cat fur fall out in circular areas, and the skin underneath will look red.  Wearing gloves will help protect you.

Cleanliness and a little precaution will reduce or eliminate most health risks.  Make sure to clean up leftover food and keep cat feces areas cleaned up.

Our TNR Assistance Program

Our TNR Assistance Program provides free veterinary vouchers for outdoor cats -- feral or barn -- living in greater Washtenaw County (see web site for service area map).

The vouchers cover the full cost to sterilize, ear-tip, vaccinate for rabies and distemper and treat for visible parasites.  Surgeries are performed at local veterinary clinics.


Because our goal is overall feline population reduction, we focus only on cats that stand the best chance of living in their habitat for the longest time.  Cats must have long-term committed caregivers providing daily food, water and dry shelter -- and the property owner's permission to live out their lives in their original habitat.  Since relocation of feral cats is discouraged, rescued or adopted cats are not eligible.


Whenever possible, young kittens should be brought indoors, socialized and then adopted out person-to-person to indoor homes.  Our Snip 'N Chip Assistance Program will sterilize qualified kittens after they are permanently situated -- but, if the kittens are still outdoors after 16 weeks they can be sterilized through our TNR Program -- provided they remain members of their outdoor colony.


An ongoing good faith effort must be made to monitor the colony and promptly sterilize all cats (male and female) -- including subsequent newcomers -- even when live-trapping is necessary.


Call us during weekday business hours for an application.  Allow 10-14 days total processing time from application to receipt of initial vouchers.  Any work done before or without vouchers cannot be reimbursed.

Some restrictions apply.  Program can be changed or modified without notice at the sole discretion of the Zimmer Foundation.

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