Examples

Birds of a feather nest together, or do they? A pond has three islands where three different species of birds nest. Bird watchers observed the 5 nests on one island, the 8 nests on another island, and the 12 nests on a third island. Of these 25 nests, 10 belonged to birds of species A, 8 to birds of species B, and 7 to birds of species C. Do birds of the same species tend to nest on the same island?

I study culturally informed technology in the context of traditional Portuguese agriculture. As recently as the middle of the twentieth century, in many of the agricultural villages in the mountainous interior of the Beira Alta region of Portugal, virtually all the land was still owned by a few wealthy families. They rented large parcels to farming families, on a more or less permanent basis. These renters owned their own traction animals and equipment and managed their farm, but hired members of the many remaining families to work for them, on a daily basis, to perform much of the farm labor. These day-workers could work for any farmer who would hire them, usually in their own village, but sometimes also in other villages. I wondered if day- workers in the same family tended to work for the same farmer, or for any farmer, or avoided working for the same farmer as other family members.