Observe nesting birds. Watch a nest for an hour each day. Extrapolate over all the daylight hours. Try to relate different calls to different situations and speculate on their function. Compare with published findings.
Many mockingbirds mimic the calls of other birds.
Try to identify them. Observe birds at feeders. Tree Studies Examine the trunks of dead and living trees in a wooded area and compare them for woodpecker holes and fungal growth. Speculate on the ecological role of dead trees. Study leafing patterns of trees or bushes.