Palaeognath birds innovate to solve a novel foraging problem

The ability to innovate implies flexible cognition, and is used as a broad metric of intelligence. Innovation in birds has been intensively studied in the larger and more taxonomically diverse Neognathae clade (particularly crows and parrots) and overlooked in the smaller and more ancestral Palaeognathae clade. The current study provides the first known evidence of technical innovation in palaeognath birds. We tested the ability of nine individuals of three species to move a hole towards a chamber to access a food reward. This problem was different to traditional innovation puzzle-boxes where an obstacle is moved away from a food chamber. Three emus and one rhea produced a wheel-turning innovation, moving the hole in the most efficient direction (closer to the nearest food item) in 90% of cases. One rhea dismantled the task twice by removing the central bolt, which we suggest is a second type of innovation, and it did not persist once they innovated the wheel turning solution. Ostriches did not innovate. We classify innovation in palaeognaths as low level/simplistic, relying on general exploration and asocial trial and error learning. Our research suggests that technical innovation may have evolved far earlier in birds than previously thought, and palaeognath birds are a compelling taxonomic group for further cognitive research.