Zebra finches select nest material appropriate for a building task

Across the animal kingdom, many animals build structures. One especially diverse example is that of nest building by birds. It remains unclear, however, what birds know or whether they learn about the structural aspects of the material with which they build a nest. Here we tested whether nest-building male zebra finches would choose the appropriate type of material when building in a novel situation. They did do this: males provided with a nestbox with either a small or a large entrance hole and with nest material of two types (‘long’ and ‘short’) chose the type of material that was appropriate for the box in which they built. Additionally, the birdsʹ material use improved with experience: males building in nestboxes with small entrances became less choosy in their material choice as they became more skilled at inserting material of either length into their nestbox. The birds, therefore, first chose the appropriate materials for the nestbox in which they were building but then modified their handling skills so as to make use of all of the available material. How the cognitive abilities used in this nest-building context compare with those used in solving other physical problems such as tool use tasks is not yet clear.