# Hoofin' It! - The Bean Counters: Mark-Recapture

### Overall Rating

Subject:
Mathematics, Wildlife Biology, Wildlife Management
Duration:
30 - 45 minutes
Setting:
indoors
Keywords:
graphing, observation

### Overview

The lesson plans in our 'Hoofin' It!' unit help students learn the basics of animal classification and what characteristics are common to mammals, mainly through studying Dall sheep.

Lesson fifteen explores how scientists estimate populations.

### Objective(s)

Students will be able to estimate population size through sampling rather than with a complete count, and be able to compare different methods.

### Background

The "Hoofin' It!" unit explores the natural resource management of Dall sheep in the national parks of northwest Alaska. Students will learn about Dall sheep, where they live, how they have adapted to their environment, and how wildlife biologists study them to understand how to protect their populations within national parklands. Links to other lessons in the unit can be found at page bottom.

Dall sheep are a wild sheep that lives on steep mountain slopes across the Alaska. The sheep are an integral part of the natural ecosystem, and they are prized by subsistence and recreational hunters. In the early 1990s, the Dall sheep population in the Baird Mountains of Noatak National Preserve declined dramatically, losing half its population in two years. Wildlife managers closed the sheep hunting season for seven years to allow the population to grow again.

Why did the population drop so suddenly? What are the natural and human factors that affect the Dall sheep population? In the spring of 2000, Brad Shults, a wildlife biologist for the National Park Service, began a research project to learn more about Dall sheep population dynamics. Shults hopes to better understand sheep by studying the number of lambs that are born, how long sheep live, what are the most common causes of death, where do they go from season to season, and just how many sheep are there?

### Materials

Each group will need a marking pen, a bag of beans, a container, a small scoop, and a copy of the Mark-Recapture Data Table.