Seeds on Our Socks

Hitchhikers on the Home Course

1Ines Varghese runs on the cross-country team at Pinecrest Middle School. The team's home course loops through a mown field, a strip of tall meadow full of wildflowers and weeds, and a paved path beside the practice fields. After a meet in late September, Ines found her socks covered with small seeds. Her coach, Dorota Halloway, who also teaches science, helped the team turn the seeds into a study.

2For five practices, six runners each put on a new pair of the same kind of white cotton socks. Two runners ran 1 km in the mown field, two ran 1 km through the meadow strip and two ran 1 km on the paved path. Afterward, the team picked every seed off the socks and sorted them by their structures: seeds with tiny hooks or barbs, seeds with a fluffy parachute of fine hairs, and smooth seeds with no special parts. They found the mean number of seeds per pair of socks for each route.

3To find out which plants grew in the meadow, the team also marked out a strip 10 m long and 1 m wide and counted every plant that held ripe seeds. They sorted those plants by the same three kinds of seeds.

4The team noticed something else on the course. At the edge of the practice field, a pair of killdeer, a kind of shorebird that often nests far from water, had laid four speckled eggs in a shallow scrape in the gravel. From a few steps away, the eggs looked like the stones around them. The two parents took turns sitting on the eggs. When a runner came near, one parent ran ahead along the ground, calling loudly and dragging one wing as if it were hurt. Once the runner had followed it far from the nest, the bird flew back. Coach Halloway set out cones so the team could measure how far from the nest each display began and ended. About 25 days after the team first saw the eggs, all four chicks hatched, and within hours they were walking and pecking at insects.