Causes and consequences of avain range expansion

当我们观察一所有人居住的房子时，我们通常可以假设这所房子是适合居住的。如果我们看到一个幸福的家庭住在里面，我们对房子的评价可能会提高。这两条线索中的任何一条都是判断房子质量的捷径，而不需要自己实际尝试。事实证明，动物评估栖息地的方式也是一样的。这种行为是在如此强烈的选择下进行的，以至于之前的实验表明，如果鸟类在那里观察其他鸟类，它们会占据不合适的栖息地(类似于人类的停车场)。

When we observe a house that is occupied, we may generally assume that the house is habitable. Our assessment of the house may be improved if we see that a happy family lives inside. Either of these cues is a shortcut to determining the quality of the house, without actually trying it out for ourselves. It turns out that animals assess habitats in the same way. This behaviour is under such strong selection that previous experiments have shown birds will occupy unsuitable habitats (akin to parking lots for humans) if they observe others there.