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POPULATION STUDY OF CHIMNEY PERCHING BIRDS

PURPOSE: To determine how different winter weather conditions influence the number of birds perching on chimneys.

MATERIALS: Luggage tag (6.5 x 13.5 cm), data sheet, glue or tape, pencil. Optional: thermometer, windspeed indicator.

INTRODUCTION: How do small animals like birds keep warm in the winter? Some birds roost together in a group to keep warm. Some find a place in the sun sheltered from the wind. Pigeons and starlings may perch on chimneys to keep warm. As a general rule, birds seem to perch where maximum heat is gained from the environment and minimum body heat is lost to the air.

How does air temperature and wind affect the chimney perching behavior of birds? In this activity, you will collect data on weather conditions and chimney perching birds over a week or longer as you travel to and from school. The information collected by your class will help you explain how the behavior of the birds helps them survive the winter.

PREDICTIONS: Three heat sources are labeled in the energy flow diagram below. The arrows from each heat source show how heat might be exchanged around a chimney perching bird. Use the diagram to make some predictions:

1. Do you expect to find more birds perching on chimneys on:

Cold days? Warm days?

Calm days? Windy days?

Sunny days? Cloudy days?

PROCEDURE:

A. Glue or tape a small data sheet on a luggage tag. Tie the data tag to your notebook or jacket. This will remind you to watch for chimney perching birds on your way to or from school.

B. Choose a route to and from school that is at least four blocks long and has about 20 masonry chimneys for you to observe. Count the number of birds on chimneys on this route on at least 4 different days. Use the tag to record your data as follows:

(1) On your data tag, keep track of the number of birds on each chimney. If a chimney has no birds on it, write "0". If a chimney has 1 or 2 birds on it, write "1" or "2".

(2) Record the wind speed, cloud cover, and precipitation on the tag.

(3) To calculate the number birds per chimney, divide the total number of birds you saw on a given day by the number of chimneys. Your data tag should resemble the sample tag after your first set of observations.

C. Transfer your data to the class data sheet every day. Record temperature, wind speed, cloud cover and precipitation for each set of observations.

D. Fill out the data calculation chart using the completed class data on #birds/chimney and temperature.

E. Using your data calculation chart, construct a bar graph with average number of birds/chimney on the vertical axis and temperature on the horizontal axis.

F. Optional: Make a scatterplot of the completed class data with the number of birds per chimney on the vertical axis and the temperature on the horizontal axis. Circle the data point(s) with high wind speed.

CONCLUSIONS: Use your data and the energy flow diagram to answer questions 2-5.

2. How did temperature affect the number of chimney perching birds? Give one possible explanation for these results.

3. How did wind speed affect the number of chimney perching birds? Give one possible explanation for these results.

4. How did clouds seem to affect the number of birds perching on chimneys? Give one possible explanation for these results.

5. Use your answers to questions 2-5 to summarize the type of weather that seems to be ideal for chimney perching:

Cold days? Warm days? No difference?

Calm days? Windy days? No difference?

Sunny days? Cloudy days? No difference?

6. How did your predictions in step 1 compare to the results in step 6?

DISCUSSION:

7. Under what conditions do you think a bird might prefer to sit on the small ledge on top of the window in your energy flow diagram? You may wish to draw a bird on the window and new energy flow arrows to help you answer this question.

8. Do you think that genetic programming or learning is relatively more important in the perching of birds on chimneys? Give your reasons.

9. How could you change the design of this study to obtain more or better data?

10. If birds could speak, what would a chimney perching starling say to convince its friend the house sparrow (who does not chimney perch) to fly up to the chimney. Include information from the class data to support your story.

11. Optional: Your scatterplot shows how the number of birds/chimney seen at a particular temperature varies from observation to observation. Give at least two reasons why different numbers of birds/chimney might be seen at the same temperatures.

DATA CALCULATION CHART

Temperature Interval	# Birds Chimney	Sum of # Birds Chimney	# Observations	Average # Birds Chimney
< -24
-24 to -20
-19 to -15
-14 to -10
-9 to -5
-4 to 0
1 to 5
>5

Note: Divide column 3 by column 4 to get column 5.

CLASS DATA SHEET

Time Data	Date Time	Date Time	Date Time	Date Time	Date Time
Weather Data	Temp Wind Cloud Precip	Temp Wind Cloud Precip	Temp Wind Cloud Precip	Temp Wind Cloud Precip	Temp Wind Cloud Precip
Bird Data Observer	# Birds Chimney	# Birds Chimney	# Birds Chimney	# Birds Chimney	# Birds Chimney

Precipitation: - clear, • rain, * snow