Menu
Back to The Life

Why do license numbers change every year?

 

Herd of wintering bull elk
Photo credit: Getty Images

Have you ever wondered how the license number system works? We talked to Colorado Parks & Wildlife to find out how big game license numbers statewide are determined every year. 

To understand how it works on a micro level, we will show you what we learned about one particular Data Analysis Unit (DAU) — Colorado’s DAU E-12. This Data Analysis Unit contains 3 Game Management Units (GMUs): 361, 35 and 36.

Some vital statistics for DAU E-12

2004 population: 6680 elk
    Bull to cow ratio: 30:100
    Calf to cow ratio: 47:100

2013 population: 3730 elk
    Bull to cow ratio: 34:100
    Calf to cow ratio: 44:100

This doesn’t mean bulls make up 34% and calves 44%, because that leaves cows with only 22%, and we know that can’t be the case because there are 3x as many cows as bulls and 2x as many cows as calves, because that’s how ratios work.

Those are the numbers as recorded during those years. Now, let’s see how this decrease in population happened over time.

Elk population of Colorado DAU E - 12, 2004-2013
Since 1988, the population objective for this unit has been 2950 elk. Through the 1990s and early 2000s, the population of the herd ranged from 5000-6800. The decrease in the population has been achieved mainly through the release of more antlerless licenses. This has worked, as the observed population has decreased steadily since 2001. 

One thing to consider in regard to population is antlerless harvest in potentially underestimated by an unknown amount due to youth harvests in the late cow season, due to the DAU being one of the closest units to Denver to offer this late hunt. Unfilled antlerless or either-sex tags from the regular season are eligible in almost any unit statewide, regardless of from which GMU the regular season license came.
 

Cow elk in snow
Photo credit: Getty Images

Underestimating antlerless harvest can result in incorrectly higher population size estimates and lower than actual success rates, meaning that more licenses could be available than intended.

Although the number of elk overall decreased in this DAU, bull to cow ratios are still high.

Why do sex ratios matter?

Bull ratios are one indicator of bull quality. In the early 1980s, the sex-ratio was too low. A 4-point antler restriction was put into place in 1986 as an effect to increase the bull ratio. Now bull to cow ratios consistently exceed the set objective.

License numbers adjust to population trends and management objectives

Tags issued vs. elk population estimate

Here’s why tag numbers change from year to year

The number of tags issued each year is directly related to what is needed to control the elk population in the desired way. Since 2001, the goal has been to reduce the overall population while still maintaining a relatively high bull ratio.
 

Small herd of elk
Photo credit: Joe Lewandowski, Colorado Parks and Wildlife

The main way this control has happened is through an increase in antlerless licenses. Since 1993, efforts have also focused on moving herds from private to public land in the form of private-land-only antlerless licenses.

Elk harvested vs. population estimate
This shows that most of the elk live instead of die. 278 total bulls were harvested in 2013 across this DAU, out of a total of 561 elk.

Tags issued vs. harvest numbers for DAU E - 12

Why were 1,862 licenses issued for 2014?

Colorado licenses issued in 2014 for E - 12

Compared to 2013, there was a 6.5% reduction in licenses issued to compensate for the elk population’s decrease in the past year.

Final facts:

  • In 10 years, licenses have reduced by 47% for E-12.
  • In the same period elk population has reduced by 44%.
  • To keep the population size stable, licenses for antlerless elk might reduce further.

Why it matters?

Elk harvest numbers and bull to cow ratios are important for the hunter to understand in order to grasp what the state is doing to tag numbers. Bull to cow ratios are an important indicator for bull quality and herd quality. Tag numbers fluctuate each year because they are directly related to controling the elk population in the state. For the past 14 years, the goal in Colorado has been to reduce the overall population while still maintaining a relatively high bull ratio. The hunting community needs to continually support conservation efforts from groups like the Rocky Mountain Elk Foundation, in order to keep elk population levels near management objectives and ensure that quality habitat remains to keep an elk herd healthy.

Comments

Log in or register to post comments.