Is Disease Now Controlling the Abundance of House Finches?
One general research goal of ecologists is to learn what factors determine the abundance of animals. Why are some species uncommon while others are so abundant? Does the availability of food limit population size? Does predation play a role? All of these questions have been the focus of research for decades. More recently, scientists have begun to ask whether diseases might also be responsible for routinely limiting the abundances of animals. For any factor (for example, food availability or disease) to regulate the abundance of animals, the effect of this limiting factor must increase as an animal population increases in size. For example, in order for food availability to regulate an animal’s abundance, denser populations would have to experience lower nesting success (not enough food to raise large numbers of offspring) or higher starvation rates of adults. Likewise, if disease regulates populations, then the disease should be more prevalent when bird populations are denser. One pre
