Avian clutch size of increasing clutch size with increasing latitude. The proximate and ultimate causes for this pattern have been a subject of intense debate involving the ideas of group and individual selection. David Lack observed a direct relationship between latitude and avian clutch size. Birds near the equator laid approximately half as many eggs as those that resided in northern temperate habitats. He observed an increasing clutch-size from the equator towards the poles (something he referred to as the “latitude trend”) for many passerine (perching) birds, near-passerine (tree-dwelling) birds and in various other groups: Strigiformes, Falconiformes, Ciconiiformes, Laridae, Ralliformes, Galliformes, Podicipedifomes, and
Which Side Are You On? but his wife, Florence, and their children were terrorized. That night, after the men had gone, Florence wrote the lyrics to "Which Side Are You On?" on a calendar that hung in their kitchen. She took the melody from a traditional Baptist hymn, "Lay the Lily Low", or the traditional ballad "Jack Munro". Reece supported a second wave of miner strikes circa 1973, as recounted in the documentary "Harlan County USA". She and others performed "Which Side Are You On?" a number of times throughout. Reece recorded the song later in life, and it can be heard on the album