Population Dynamics in Animal Welfare

Wild Populations

One of the main goals of engaging with feral cat populations is to bring the number of cats down to the carrying capacity in your area. Pretty simple. Or is it? Basically, carrying capacity is maintaining the number of animals to a level that is not detrimental to the animal’s population or the environment. Pretty simple stuff; keep the animal population to the level that the land can support it. Oh, but there are so many things that can go wrong.

Several years ago, communities were trying to understand how their local efforts at Trap, Neuter, and Release or TNR were failing, in spite of all their efforts to sterilize all of their free-roaming cats. One of the big obstacles was little old ladies in white tennis shoes (LOLWTS). Who can watch an animal starve? So, these folks began changing the dynamics of the carrying capacity of their neighborhoods by feeding the feral cats that come into their yards.

As long as there is a food source, animals will breed. Even though the communities have spent a small fortune in sterilizing their feral cats, there are always enough fertile cats to join the cause to breed. Most of the fertile cats were indoor/outdoor cats owned in the neighborhood or abandoned by a previous owner. TNR programs failed when they believed that they had their feral cat problem under control. The current population of cats increased as cats immigrated into the area and others were abandoned by their owners. Soon, these fertile cats started causing the population to climb again.

The climbing population of cats resulted in neighbors calling their local animal control officer to trap and remove the cats. Those trapped cats create an unnecessary burden on the animal shelter and place the shelter’s animals at risk. Feral and outdoor cats are largely unvaccinated. When an unvaccinated animal enters the stress of being trapped and caged, the animal becomes susceptible to disease. We had an extremely difficult time maintaining the health of our cat population in Roanoke because the animal control officers in one jurisdiction kept rounding up the sick feral cats in their jurisdiction which provided a constant source of sick cats to the animal shelter. As a result, many potentially adoptable cats were prevented from finding new homes because of the constant quarantine conditions that the shelter was experiencing.

In Jacksonville, we were so effective in removing the nuisance feral cats in one neighborhood that neighbors began to complain of the rise in the rodent population. Jacksonville is home to a Norwegian Rat that grows to the size of a large cat. The neighborhood didn’t understand the benefit that their feral cat population provided and incurred larger problems in the removal of the cats.

Mother Nature provides a great equalizer for population control. Her efforts are frequently disturbed by human intervention; whether it is backyard feeding or animal removal programs. Ironically, as the shelter fills up with sickly feral cats, the carrying capacity of the area where the cats were removed opens up to new arrivals.

TNR is a short-term solution. It just seems like it takes forever. But when you announce your success and curb your TNR efforts, mother nature will begin to swart your original efforts. TNR isn’t a won-and-done proposition. Since you have already interfered with the carrying capacity of your program area, you’ll will need to continue those trapping efforts to ensure an ongoing effort to keep those cat numbers to a minimum.

I have always believed that the solution to the feral cat problem is an oral sterilant, that was used in controlling wildlife populations. The advantage of an oral program is that it treats both wild and domestic free-roaming animals. The offside is the effect that it would have on young children that seem to pick up and eat anything they find lying on the ground. Adding a rabies vaccination to the bait would help keep rabies under control and help minimize children running around biting one another.

Shelter Populations

A veterinarian once told me that the best way to keep disease down in your shelter is to keep the population of animals to a minimum. As the population of animals increases in an animal shelter, the stress of the animals rise. Stress weakens the immune system and disease outbreaks become common.

A feral cat may keep an illness under control until that cat undergoes the stress of being captured, caged, and confined. Illnesses in feral cats begin to manifest after three or four days in captivity. Then shelter staff, in their routine of feeding and cleaning, inadvertently begin spreading the illness to the rest of the cat population in the shelter. Then you have an outbreak.

Disease within an animal shelter population is generally spread by direct touch. Shelter staff need to clean themselves between cleaning each cage. Shelter visitors need to keep their hands to themselves. It is not uncommon to watch a visitor going down the line of cages petting one animal after another. Each touch creates an avenue for disease to spread.

When dealing with internal and external population limits, animal welfare staff have to consider what is in the best interest of the community’s people and animals. And always remember that Mother Nature (and well-intended people) will be constantly battling you along the way


War on Cats

I read an article this morning about Australia declaring war on feral cats.  The feral population has grown so large that their government is worried about the impact that the cats have on other species.  They have started putting a bounty on the cats. 

Australia is not alone with this problem.  In the United States, we have been fighting this problem for years.  At one time or another large communities have discussed methods to reduce the feral cat population.  Many community begin by trapping, neutering, and releasing the cats back where they were found.  TNR programs are considered a humane way to deal with the surplus problem.

The idea behind TNR is to create a community of infertile cats.  It is believed that every area has a maximum carrying capacity for a specific species and that by loading up an area with cats that cannot reproduce will eventually lead to reduction of the cat population.  In theory, it looks good on paper.

The problem is that people caused the problem of feral cats and humans continue to undermine the success of feral cat programs.  Although Mother Nature has a specific carrying capacity for any species, that does not keep us humans from messing it up by leaving food out for the cats and increasing the capacity for an neighborhood to support more cats.

In Jacksonville Florida, we had a problem in which groups of citizens took it upon their selves to set up shelters and feeding stations for feral cats throughout the city’s parks.  Some engaged in TNR, but many only had the funds to just buy food.  The Parks Department was not very happy with the increasing amount of feces deposited where children were playing.

One neighborhood in Jacksonville took on the challenge of removing all of their feral cats, only to discover that rats moved in.  Clearly the art of dealing with feral cats needs to be balanced.

Our government created food pellets that could vaccinate raccoons for rabies.  I had always wished that someone would create food pellets that would vaccinate and sterilize cats.  This sounds like such a simple solution to our feral cat problem, until you begin to worry about non-target species, for example: children picking up the pellets and eating them.  Kids do stupid things like that.

TNR is part of the solution, but we are still dealing with the pet owners who moves out of town abandoning their fertile cats.  Differential licensing fees work in many area where infertile pets are licensed are a ridiculously low fee and fertile pets are licensed at a much higher fee.  In Gainesville Florida, the owners of impounded fertile pets had a choice to pay a lower reclaim fee if they allowed us to sterilize their pet.  After all, animals that are running at large are the problem.

We have a lot of citizens who just refuse to do the right thing.  We create laws, in hopes of regulating their bad behavior.  Unfortunately, these folks don’t care very much about following rules or laws.  It is because of people like this, that Australia had to declare war on cats because people along the way failed to do the right thing of controlling or sterilizing their cats.  Australia is proof that many people do not have what it takes to be a responsible pet owner.

In Salt Lake City, we had an education program in which we went into all of the elementary schools to teach humane education to 3rd and 5th graders.  One of the favorite parts of my job was to listen to parents complain to me that their child came home from school and pointed out that they were bad pet owners.  It gave me an opportunity to remind them of their responsibility to set a good example for their children.  We hoped that this program would create a whole new change in pet ownership for the next generation.