In response to environmental pressures, many species of birds have developed the practice of nesting in colonies. A. The abundance of food on rocky islands makes them an attractive environment for bird species that nest in colonies, including the yellow-rumped cacique. B. Because they are not able to physically defend themselves from predators, yellow-rumped caciques rely on hiding their active nests among empty nests to confuse predators. C. The concentration of bird colonies along coasts makes their inhabitants especially vulnerable to food shortages and weather-related destruction. D. The challenge of protecting nests and newborn chicks from predators is a major contributor to the evolution of large colonies. E. Colonial life provides birds with benefits besides protection from predators including help with finding food. F. There are some disadvantages associated with life in large colonies like the increased rate of infestation by parasites.