Deer Options Enterprise

Biological vs Social Carrying Capacities


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Relating to Urban Wildlife
Dealing with rodents, feral cats, deer, and other urban wildlife

Presenters: Max, Muller, Robinson

Peter Muller
C.A.S.H. - Committee to Abolish Sport Hunting,


“Urban Wildlife” or “Nuisance Animals?”

When we deal with a human-wildlife conflict in an urban or suburban setting – we must keep in mind that what is not seen as a problem from our perspective is -- frequently perceived to be a problem from the complainants’ perspective.. The complainants and we are living in different cultures. Many of us live in the nature-embracing culture whereas the complainants live in the nature-alienated culture. We are not likely to be effective if we try to proselytize our culture rather than address their perceptions.

A typical example consists of some residents complaining to the town board that there are too many deer in the area and demand that something be done about it. If a homeowner tells the board “The deer are eating all my tulips and shrubs; they are causing thousands of dollars worth of damage” it would do very little good to respond with “That’s what plants are for– so what’s the problem?”

We know that from an nature-embracing perspective that various plants evolved in the eco-system to provide food for a variety of animals – and so it is normal, good and proper for deer eat plants. From the nature-alienated perspective of the typical suburbanite this is an invasion of his property and a destruction of his assets. No matter how wrong-headed this perception strikes us it is that perception that we must address. The nature-alienated perspective represents the politically and economically dominant culture today and that is what we must deal with it.

To say, “there are too many deer (geese, raccoons, coyotes, etc.) in this area and we have to do something about it” – is, in an ecological sense, not a problem that requires human intervention. An area has a biological carrying capacity for each particular species of wildlife. If the population size of a species exceeds the carrying capacity -- nature quickly and efficiently adjusts the size of the population of that species so that it is again at or below the carrying capacity. Clearly the complaints of the nature-alienated homeowners are not making a statement about the biological carrying capacity. Their perception of an excessive population is termed “the social carrying capacity.” The social carrying capacity is the population size of a species that the human community is willing to tolerate; it is a very subjective measure.

The general approach would be to get the complainants to agree to a social carrying capacity that is acceptable to them and the show them how that can be realized without using lethal methods. That may not be as easy as it sounds. Some residents are so totally alienated from nature that their aversion to seeing wildlife is a phobia rather than a rational concern about damage to their property. For them the social carrying capacity is zero.

Normally we can move away from zero to a somewhat larger number. Many complaints will begin with “I don’t want to see all the geese removed, I enjoy seeing some geese around the lake but....” We have to persuade them that the social carrying capacity acceptable to them can be achieved by employing non-lethal methods.
We should also get them to agree that although geese are not acceptable over here (on the soccer-field, on their lawn, on the school play ground, etc.) there is no problem if the geese hang out over there (on the far side of the lake, 100 yards north of the playground etc.) Get them to agree that some areas should be essentially goose-free whereas other areas can contain geese without any conflict.

A variety of non-lethal methods are known to be effective in dissuading geese from staying in specific areas. There are, unfortunately, many attempts at lethal control methods that can be cited that were expensive and ineffective.

The basic strategy to a sensible solution to a perceived human community – Canada Goose conflict starts out by explaining what constitutes a goose-friendly environment.

Canada Geese are attracted to areas that approach to following “ideal” conditions:

  1. Short cut grass

  2. Access to water without barriers

  3. Unobstructed view of ambient areas (no trees, bushes, shrubs)

  4. No harassing objects or animals

If those conditions met (or are close to being met) Canada Geese will settle in to that area. To dissuade them from that areas the landscape must be altered to make it less goose-friendly. At nearby areas where the geese are not in conflict with the human community these conditions should be cultivated

One common “lethal” method that has been, and still is being implemented in some regions is rounding up the geese during their molt (when they can’t fly) and killing them.

Removing geese from a goose-friendly area (either by killing them or relocating them) is not going to be neither effective nor cost-effective because other geese will settle in from nearby, less than ideal, areas once the goose-friendly area has been vacated. Rounding up and killing geese costs about $75 per goose.

In Clarkstown, NY in 1997 about 100 geese were rounded up from the town parks and killed. Two weeks after the roundup the numbers of geese in the parks was again at the same number as prior to the roundup.

Similarly, more recently, in Kent, NY Lake Carmel, NY and in Sullivan County NY – whenever roundups were used – new geese settled into the cleared areas in a very short time,

After the Clarkstown town board was persuaded to try non-lethal methods the playing fields and picnic areas in the parks contain no more Canada Geese than the acceptable to the people that use those areas.

The primary non-lethal methods are:

1) habitat modification

a. placing barriers between grassy area and water (plantings or fences)
b. letting grass grow longer
c. planting bushes and trees to eliminate a clear vie of the ambient area
d. application of chemical goose-dissuading sprays

2) harassing

a. border collies
b. noise makes (prior to nesting)
c. laser lights
d. high intensity flash lights

It’s open to question whether or not egg-destruction is a lethal method or not. Egg destruction by addling or oiling can effectively reduce the number of goslings. It’s the least preferred method, in my view – but it is better than killing hatched, live birds.