Imagine crouching behind a bush, doing your best to be still and quiet so as not to alarm the herd of elk 150 metres in front of you. With your binoculars, you study the group from your hiding place, carefully taking notes. You are a wildlife biologist and for the past few weeks, you have been surveying elk herds in the area to determine the health of the local population. Your department will use this information to determine how many elk hunting tags can be issued this year.

Every year, thousands of hunters apply for a licence to hunt elk, but the existing populations can't sustain that many losses from their herds. You survey these populations to determine how many animals the population can afford to lose, which will determine how many hunters will be granted licences and allowed to hunt mature elk.

As a wildlife biologist, you know how dangerous overhunting can be to wild game populations and how critical this survey is to the proper management of local elk herds. For the herd you're watching today, you count their numbers to measure the herd's size. But this alone won't tell you how many hunting tags can be issued this year. You must also look at the herd's makeup, which will indicate other factors that could be affecting the population.
 

First, you count the number of males and females the herd will need a certain number of each in order to reproduce. You also look at the relative age of the elk, particularly how many mature animals there are, how many adolescents, and how many of last year's young have survived. There must be enough young elk to replace the older ones as they die.

After gathering as much information as you can on the area's elk herds, you will compare that to data from years previous to get an indication of the population growth or decline. If the population is growing, you can use the information to determine how much hunting should be allowed.