What Seeds Do Birds Prefer to Eat?

1. Do background research on the birds in your area and their feeding preferences. Then decide which types of seed you want to test.
2. Build your bird feeding platform.
   1. The platform is a simple square of plywood material, with strips of wood glued or stapled on top to divide the platform into four equal quadrants (see Figure 1, below).
      

      Figure 1. Top view of bird feeding platform. The surface of the square piece of plywood is divided into four equal quadrants using 3/4" wide by 1/4" thick strips of wood (exact dimensions not critical). In each quadrant, a bottle of seed (see below) is mounted on a 3/8"-diameter dowel.

   2. In the central corner of each quadrant, drill a hole and glue a 6 in (about 15 cm) length of 3/8 in (0.95 cm) dowel in place. The four seed bottles will be mounted to these dowels.
   3. You'll need to drill holes in the seed bottle caps so that the seed can come out. Make a '+' pattern with four separate holes, as shown in Figure 2, below. The holes are shown in gray. Knock out the central area if any plastic remains.
      

      Figure 2. Hole pattern for seed bottle caps.

   4. Optional: if there are squirrels in your area (often the case), you may find that your bird feeding platform becomes a squirrel-feeding platform instead. To prevent squirrels from raiding the bird seed, attach a piece of sheet metal to your feeder's mounting post, either in an upside-down funnel or cylinder shape as shown in Figure 3, below.
      

      Figure 3. Two different methods for keeping squirrels away from your bird feeder. Attach a piece of sheet metal to your feeder's mounting post in the shape of an upside-down funnel (left) or cylinder (right). (Feeder images ©Project FeederWatch, 2007, used by permission.)

   5. Optional: depending on how much precipitation you get in your area, you may want to consider making a cover for your feeder. Think carefully about the dimensions of your design. You want to make sure that your feeder can accommodate all of the birds that are likely to visit in your area.
3. Load up the containers with seed. The bottles can be mounted to the dowels with a rubber band or cable tie. Mount the bottles upside down, so that the caps are slightly above the surface of the platform, allowing some seeds to fall out. The seeds on the platform should then block the hole. As seeds on the platform are eaten by birds, more will fall out of the corresponding bottle so that the platform has a constant supply. Test to see that each seed bottle dispenses seed as expected, and make any necessary adjustments (e.g., change mounting height, enlarge dispensing hole) before starting your experiment.
4. Measure and record the height of seed in each bottle, and the time that you made the feeder available for birds.
5. Mount the platform on a sturdy pole or post in a convenient location both for bird access and for viewing/monitoring. It is ideal if you can view the platform from a window in your house.
6. Monitor the feeder at regular intervals to see what birds visit.
   1. Use your field guide to identify visiting birds.
   2. In your lab notebook, record the number and type(s) of birds that you see, and the time that you see them.
   3. If you have a camera, take pictures of the birds, using a telephoto lens, if possible. The pictures will aid in confirming your identifications of the birds, and will add interest to your project display board.
   4. Keep an eye out for squirrels, and take measures to keep them from raiding the seed, if necessary.
   5. To get an estimate of the amount of seed consumed for each quadrant, measure the height of the seed remaining in each seed bottle. Subtract this from the previous height measurement to see how much seed was consumed in the preceding time period. (Alternatively, remove each bottle and weigh it.)
   6. Re-fill bottles as necessary to assure a constant supply of seed. Be sure to record the new seed height (or weight) and time when bottles are refilled.

Ideas for Analyzing Your Data

1. At what time(s) of day is your feeder most frequently visited?
2. Do times vary for different species?
3. Do different species prefer different seeds (and thus different quadrants of the feeder)?
4. Which seed(s) are most popular?
5. How much of each seed type, on average, is consumed per day? Make a bar graph to compare the different rates of consumption.
6. Which types of birds are the most frequent visitors? Can you think of a way to estimate the number of birds that visit your feeder each day? Can you estimate how much seed is consumed per bird per day?