According to the passage, populations of insects preyed upon by pied flycatchers A. are finding less food as temperatures rise in the Eurasian forests that they inhabit B. are endangered because of global warming C. have recently experienced changes in the timing of their life cycles relative to the calendar D. have recently begun inhabiting cooler climates largely unfrequented by pied flycatchers. E. have increased significantly because of lack of predation.