Feeder Bird Identification and Food Preference

• What types of food are feeder bird’s beaks adapted to eat?
• What is metabolism?
• How does a bird’s metabolism compare to a human’s metabolism?
• What types of seeds or other bird foods have the highest fat content?
• What is a niche?
• What niche does each of the birds that visit the feeder fill in their ecosystem?

Unlike humans, who in most cases have the opportunity to choose from a wide variety of natural and un-natural food items, animals must make a choice of which food will sustain their metabolic needs while minimizing the amount of energy it takes to forage for food. Food preference will depend on several factors, including beak shape. Most of the birds that come to a bird feeder to eat seed will have beaks shaped for cracking open seeds. Another factor is temperature and time of year. A bird that must keep itself alive through sub-zero temperatures will need to seek food with a higher fat content. A bird that has access to alternative food sources because they are in season will not be as dependent on a bird feeder. Competition between birds becomes a factor as well. More aggressive birds will dominate a feeder. Although the task is fairly simple, considering all of the factors involved in a bird’s food choice becomes quite complicated, intertwining many aspects of population biology and animal behavior.

The materials for this project are available at a variety store like Wal-mart or Target, a farm supply or feed store, or hardware store.

• Black Oil Sunflower seeds
• Cracked corn
• Thistle
• Striped Sunflower seeds
• 4 of the same bird feeders
• Stopwatch
• Bird Identification book for your region
• Binoculars

1. Fill each of the bird feeders with one type of food. Assign each feeder a number so that you can keep track of them easily later on when you are collecting data. Black oil sunflower seed = 1, Cracked corn = 2, Thistle = 3, Striped sunflower seed = 4.
2. Hang the bird feeders for a week before you begin collecting data. This will allow the birds time to find the feeders and establish themselves in the area. Be sure not to let the feeders go empty during your experiment or the birds might go elsewhere to find food and this will affect your data collection.
3. During the first week spend some time identifying the birds that come to the feeder.
4. During the second week you will begin your data collection. You might want to have someone help you collect your data as the birds move quickly.
5. When you are ready to collect data: set the stopwatch for 3 minutes. Observe only feeder # 1 for the three minutes. Note each time a bird collects a seed from the feeder and what type of bird it is. This is where an assistant may be helpful, so that you can call out the bird type while they record it or vice versa. Set up your data sheet ahead of time so that you can quickly make tally marks while you are observing. You will find an idea for setting up your data table below. (Table 1) The birds will move quickly so you need to be ready. You may want to observe with binoculars.
6. Now reset your stopwatch for 3 minutes and observe and collect data at feeder # 2.
7. Continue until you have observed all feeders for 3 minutes each.
8. You may wish to do more than one observation for each feeder each day. This is up to you. However you choose to do make your observations it will be important to be consistent with your data collection. Note the time when you make your observations, the time of day is important when drawing conclusions.
9. Observe your feeders consistently for at least 2 weeks.
10. Compile your data. You may want to use a pie chart to show your data. There are examples below. (Figures 1 and 2)
11. When compiling your data, consider the nutritional value of each type of seed or food, the bird’s beak shape, the behavior of the bird (is it aggressive or passive?) etc. You may want to show this information graphically as well. There is an example of a bar graph to show the nutritional value of the food below. (Figure 3)

Terms/Concepts: Metabolism; Nutritional value of food; Variables; Competition; Niche; Adaptation; Pie Chart

References:

• National Bird Feeding Society www.birdfeeding.org
• National Wildlife Federation: Which Bird Seeds are Best? http://www.nwf.org/News-and-Magazines/National-Wildlife/Birds/Archives/2010/Bird-seeds.aspx
• Nolting, Karen Stray, Jonathan Latimer and Roger Tory Peterson. Backyard Birds (Peterson Field Guides for Young Naturalists). Sandpiper, Boston. 1999.