SEED PREFERENCES OF WINTER BIRDS

PURPOSE: To determine seed preferences and feeding behavior of winter bird species.

MATERIALS: Two bird feeders, sunflower seeds, finely cracked corn, bird field guides, stopwatch.  Optional: binoculars.

INTRODUCTION:  By the time the temperature drops below freezing and the snow is on the ground, most insect-eating birds have flown south for the winter.  The birds that stay behind mainly eat seeds and fruits available in winter.  The niche, or ecological role, of each bird species is defined by how the birds use the environment, including what and where they eat.

This activity focuses on two factors which influence the feeding behavior of birds in the winter: seed type and feeding location.  Two bird feeders have been established, offering sunflower seeds or corn to area birds.  The birds can take seeds from each feeder, or from the ground below each feeder.  You will describe the behavior of the birds that visit each of the four feeding sites.  You will then look for relationships between the food preference and behavior of the birds, and their body size and bill structure.

PREDICTION: Use what you know about birds, sunflower seeds, and cracked corn to make a prediction.

1.  Is the size of a bird's body or the shape of its bill related to the kind of the seeds it eats?  Explain your ideas.

PROCEDURE: The class should be organized into four groups.  Each group should collect data at one of the four feeder sites high sunflower, low sunflower, high corn, low corn.

A.  Complete one or more Feeder Data Sheet(s) for your feeding site. Divide the following tasks among the members of your group:

TIMER: Keep track of time for your group.  Birds must be counted at your site during four separate time periods spaced throughout the class period.  Your teacher will tell you how long the counting periods should be.

COUNTERS: Count the number of birds of each species that ARRIVE at your feeding site during the four observation periods.  Use the Bird Count Data Table to record your results as follows:  Before you start, make sure you can identify males and females of each bird species.  At the beginning of each counting period, use tally marks (||||) to record the number of birds of each species already at the feeder.  After that, record each bird that lands on the feeder.  DO NOT RECORD ANY DEPARTURES.

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EXAMPLE DATA TALLY
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4 sparrows present at station during whole 
count period                                      sparrow |||| 

1 chickadee present at feeder initially, 
leaving and returning 2 more times                chickadee |||
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The differences between the feeding patterns in the example will be recorded by the Observers.

OBSERVERS: Write detailed observations on how each bird species behaves at your feeding site.  Before you begin:  Make sure you can identify both males and females of each bird species at the feeding site.  Study the Bird Behavior Data Table.  It describes the behaviors that you should look for and record.

C.  Share your data with the class.  Each student should complete a Class Data Sheet.

CONCLUSIONS:  Give specific examples from class data to support your answers to questions 2-6.

2. Which bird species preferred sunflower seeds?  Cracked corn?

3. Is bird body size related to the size of the seeds eaten?

4. Is there a relationship between the bill size of the birds and their seed preferences?  Was your prediction correct?

5. Which bird species preferred to eat on the ground?  On the feeder?

6. Is there a relationship between the size of the birds and the preferred feeding location?

DISCUSSION:  Give specific examples from class data to support your answers to questions 7-9.

7. Do seed eating techniques differ between large and small birds that eat sunflower seeds?  Explain your ideas.

8. Do seed eating techniques differ between large and small birds that eat corn?  Explain your ideas.

9. Do large birds show a different pattern of visits to the feeders than small birds?  Consider the number and length of visits when you explain your ideas.

10. Do you think that the placement of the feeders could be important in the choice of where to feed? Explain your ideas.

11. What factors, other than seed size and caloric content, might be important in the choice of seeds by birds? Explain your ideas.

12. How could you change the design to obtain more or better data?

CLASS DATA SHEET

BIRD COUNT SUMMARY TABLE:

BIRD BEHAVIOR SUMMARY TABLE

FEEDER DATA SHEET

BIRD COUNT DATA TABLE:

Feeder Site:______________ Observer Name:__________________

BIRD BEHAVIOR DATA TABLE:

Feeder Site: ________________ Observer Name: ________________