"And how do do you know when you are managing a wild animal population?"

Leading question! First, we may not be managing an animal population. We may not need to. We are managing a resource, the wild animal resource. Some will say, "Because I say that I am!", (not very satisfactory). Others take the negative: It is the difference between what agencies do when they have wilderness and park-like areas...and other areas.

But how do you know when you are managing (ignoring for the time whether you are doing it well or not)? There are many ways to know things (epistemology), but perhaps there ought to be some agreeable way to know about wildlife resource management. You can say what you do, as in the definition, but what should we expect to see? What evidence would be acceptable? In the public agency, what is the contract with the public? What should they expect as proof of a manager having "managed"?

Wildlife managers manage whole systems, at least viewed as one resource-system for a region and a period. The above questions are about the system performance, and by inference, the performance of the manager of that system. A manager can list many activities, things that they do, but the question usually dodged is that of the performance measure. The field person often gets the question of "how are things?" and rarely knows how to answer and quickly turns attention to the weather. The question is about the performance measure, but it is unclear just what that really is.

Typical wildlife agency performance measures are hunters buying licenses and county-level or statewide game harvests. They may suffice for some managers but increasingly they become estimates of thousand hours of quality-weighted hours spent in animal-related activity.

Managers produce annual reports, usually usually about their miles of roads built, meters of waterfowl dikes replenished, acres fertilized and limed, feeding areas constructed, nest boxes placed, miles of boundary marked, arrests made for poaching, trees girdled to open the understory, acres flooded for waterfowl, and survey-routes run. These are all actions, processes within the system. Presumably they were done for a reason and the question is: what is that reason...and were you successful? The answer is: all of these things, some together (and only sensible if done together), were done to achieve a set of objectives. These are system processes, not outcomes.

The objectives are many and complex and some are difficult or expensive to measure, and so managers have picked one or two things that suggests how well we are achieving all of them. We use system performance measures.We may plot the reported annual harvest of wild turkeys. We know this is limited because the reports may be limited and law-violations are well-known (but there have been few studies of the magnitude). We report the annual harvest but we realize that the population this year was very much a function of the populations present over at least the past 2 years. We are unclear about the sex or ages of the birds taken. We study the turkeys because their habitat (read "faunal space") requirements range from grassy areas to mature forests so if the turkeys are doing well (that is, a population is doing well enough to stabilize or increase even under fairly presumed-constant hunting pressure), then animals that depend on small units of this range of young-to-old habitats are probably doing well. The wild turkey harvest is a system performance measure. Of course it is flawed! It is a performance measure, not the performance itself, but since we cannot or do not know how to communicate that, we use a "measure." There may be several measures. Too many confuse the users. A measure, by nature, is a simplification. It is the same type measure used to express the national economy (e.g.,the Dow-Jones), the state of the nation (the gross national product), or the status of an industry (e.g., the cars leaving the line)...but all of these are flawed...but decision makers, knowing they are flawed, still use them.

Use is the argument of the pragmatists. Good? Used well? Over-inflated? Use is a poor argument and begs for an alternative.

Reported harvest (H) is interesting but harvest per hunter (h) may be a better statistic to use as a performance measure. Harvest per hour spent (S) (averages obtained from hunter interviews) may be an improvement. Area of habitat (A) can be grossly mapped and included. Thus an index (K) can be devised that might allow in a word the question of "how are things?" to be answered:

K = H h S

For example on a 30,300-acre managed area, where 90 birds are taken and the average hours spent in a season is 15.6 per bird taken,and there are 777 hunters, the unsuccessful ones spending 19.4 hours, then

K = (90 x 15.6) + ((777-90) x 19.4)

K = 14,732

K expresses the hours of turkey hunting provided by the management area. Other performance measures could have been the kill per hunter (0.0116), the harvest per 1000 acres (2.7), or the hours produced per acre (0.486). The index can become very complicated but computer assistance is readily available. Not so readily available is the answer to questions such as what are we trying to show? Are we producing animals or hours of hunting experience? What happens to the index if the hunters decrease (maybe the kill per hunter will increase!) What happens to the index if the hunters become more efficient? What happens if there is a forest fire and the area of habitat increases one year, declines the next? Besides, perhaps the objective was preserving an endangered ecological community. Turkey harvest may be irrelevant. Even complicated performance indices may fail to capture the essence of why the managers are at work. I call the complicated indices "magic numbers" because few people will ask about their derivation (or understand the answers). It is possible to get indicators of how well a system is performing and to take out some of the annual variability out of them due to rules, regulations, gas prices, land use changes, and local population fluctuations. Kill per hunter per 100 acres per day of the season is an example. The per...per...per gives it away. One systems person joked that if you give any biologist a columns of numbers, he or she will divide one by the other. The modern wildlifer wont and will realize that a complex performance measure, an index, can be very dangerous. Very different states of a system can produce the same index (e.g., K = 3 / 10 vs K = 0.891 / 2.93).

There has to be a way out of this mess. There is. First, system performance indicators are designed to reflect how systems are performing. As compared to what? Hopefully, to objectives. Thus, as will be said and will be evident soon... as compared to objectives. Few wildlife managers (or their agencies or companies) have clear objectives, thus "as compared to what?" has little meaning. The objectives are essential for clarifying what the system should be doing, then a measure, some estimate, something that reflects the major aspects of those objectives, can be devised.

Next, do not use magic number indices for the above reasons. There can be equifinality; the different conditions can produce the same result.

Do use regression. Once the performance measure (e.g., cars passing an entrance point) is selected, then call it the "dependent variable" and develop regression equations (at least simple linear ones; later get help with developing multiple regression and logistic regression procedures that estimate the probability of an event).