托福听力

🎧 听力原文

Listen to part of a lecture in a biology class. The professor is discussing the behavior of a particular species of bird. "Today we're going to talk about the American robin, a bird you're probably familiar with. But what you may not know is how its migratory patterns have changed over the past few decades. Traditionally, robins were considered short-distance migrants, moving south in the winter and returning north in the spring. However, recent studies have shown that many robins now stay in the northern parts of their range year-round. Why is this happening? Well, one factor is the increased availability of food during the winter months, due to ornamental plants in suburban areas that produce berries. Another factor is climate change, which has led to milder winters in some regions. Interestingly, this shift in migration behavior has had effects on the robins' breeding cycles. They are now beginning to nest earlier in the spring. This earlier nesting could have both positive and negative consequences. On the positive side, it may allow them to have more than one brood per season. On the negative side, if they nest too early, a late frost could destroy their eggs. So, while the robin is adapting to new conditions, it's not without risks."