Cognitive adaptations in tool-using birds

Identifying the environmental and social factors that drove the evolution of human and animal intelligence is of great interest in the field of ethology. Recent research has revealed that several bird species rival primates in tool manufacture, mental time travel and social cognition, although they do not have comparable brain structures. This indicates that the underlying cognitive abilities have evolved independently in primates and birds and has raised intense debate about the selective forces behind this parallel development. The use of tools can be observed in several bird and primate species and is prominent in this debate. There are different evolutionary scenarios how tool use and the evolution of cognition could be linked: Innovation, fast trial-and-error learning, enhanced abilities to learn about spatial relationships and even causal reasoning may have been pre-requisites for the development of tool-use. However, once tools are used, selective pressure to improve this important ability may have contributed to the further evolution of intelligence. Testing the evolutionary hypothesis that use of tools has co-evolved with enhanced cognitive abilities is only possible with a comparative approach. Ideally, this comparison should comprise distantly related tool-using species in order to see whether their cognitive abilities have converged, and also a comparison of tool-using species with non-tool-using relatives to see whether the tool-using species have enhanced or different cognitive abilities. The aim of the proposed project is to investigate the role of tool-use in the evolution of intelligence, by comparing the performance of two distantly related tool-using bird species, the woodpecker finch and the New Caledonian crow, in a series of experimental tasks. If tool-use has co-evolved with certain cognitive abilities, then the abilities of the two tool-using species should have converged and the performance should be similar. However, I will also compare the performance of both tool-using species with a non-tool-using close relative (the small tree finch and the rook, respectively) in the same experimental series. If the use of tools has coevolved with enhance cognitive abilities, the two tool-using species should outperform their non-tool-using relatives. The comparison between two bird families will allow me to see whether the patterns of divergence are similar in both families. This experimental study should lay the groundwork for future comparative studies with other tool-using taxa, such as primates.