The relationship between the size of a bird and its perching behavior
The materials required for the experiment are as follows:
- a long ruler (transparent)
- a roll of duct tape
- a measuring tape
- an overhead power cable line or telephone line on which birds can perch
- a calculator
- 2 sticks
1. For this experiment, the independent variable is the species of the birds that perch on a selected overhead power cable line (look for crows and sparrows in particular). The dependent variable is length of the distance between the birds when they sit on the cable. Position a ruler at a particular distance from the poles and calculate the length of the distance between the birds using ratios. The constants (control variables) are the distance between the ruler and the cable, the distance between the poles and the types of birds observed.
2. Look for overhead power cables or telephone cables that crows and sparrows often perch on. Using 2 sticks and duct tape, mount the ruler horizontally, some distance from the cable poles. When viewed from a selected position through the ruler, the two poles should be seen between the 2 sticks.
3. Measure the distance between the 2 poles using a measuring tape. Also measure the relative distance between the 2 poles, with the help of the ruler. The length ratio is to be the actual distance between the poles divided by the measured distance between the poles as recorded on the ruler.
4. When the crows or sparrows are sitting on the cable, measure the distance between them as through the ruler. Multiply this by the length ratio to obtain the actual distance between the birds. Do this with 5 pairs of birds of each species and record the readings in the table below.