Causes and consequences of avain range expansion

当我们观察到有人住的房子时，我们通常会认为房子是可居住的。如果我们看到里面住着一个幸福的家庭，我们对房子的评价可能会提高。这些线索中的任何一个都是确定房子质量的捷径，而无需亲自尝试。事实证明，动物也以同样的方式评估栖息地。这种行为是在如此强烈的选择下产生的，以至于之前的实验表明，如果鸟类在不合适的栖息地（类似于人类的停车场）观察到其他鸟类，它们就会占据那里。

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.