Bowerbird creates an illusion
The researchers turned the order of the objects around. The largest objects were placed near the females and the smallest near the stage. This way they could investigate how important the optical illusion is for the male. Within three days the males had put the objects back in their original order.
According to the researchers the bowerbird is the first non-human animal species that uses optical illusion to mislead others. This shows that bowerbirds not only use structure and colour (some kinds of bowerbird only place blue objects in their bower) but also use the geometry of the arrangement.
Back to the bowerbirds. After the females have gathered, the show can start. The male shows himself to the females and waves around a bit with a colourful object. This is followed by a strut across the stage and then the females that are up for it can mate with him. The females build a nest themselves (not at the bower) and take care of the breeding.
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