Large birds -- our closest relations to dinosaurs -- are capable of technical innovation, by solving a physical task to gain access to food.
This is the first time scientists have been able to show that palaeognath birds such as emus and rheas can solve tricky problems.
In the study, published today in Scientific Reports, emus, which have previously been called the 'world's dumbest bird' were able to create one new technique to access food (lining up a hole with a food chamber) and moved the hole in the most efficient direction towards food in 90% of cases. A male rhea used this technique but also created a second one, rotating the bolt in the middle of the wheel until the task fell apart.
Lead author Dr Fay Clark, from Bristol's School of Psychological Science, explained: "A large body of research shows that crows and parrots are effective problem-solvers, and while scientists have recently taken interest in other birds like gulls and birds of prey, all of these birds belong to the same phylogenetic group, Neognathae.
"The problem? The more we study the same species repeatedly, the more we create an 'echo chamber' of knowledge and create a false impression that other species are less 'intelligent' but in reality they haven't been studied to the same level."
Working with three palaeognath species at a local zoo, they based their research on previous research using a rotating wheel that that had to be moved to align with a hole for a food reward. Each species -- emus, rheas and ostriches -- were given the test in ten sessions.
This particular set of ostriches did not innovate.
Dr Clark explained: "We classify palaeognath innovation as low level or simplistic -- and it is certainly not as complex as the innovation we see in crows and parrots.
"However, it is still a very important finding.
"There were no reports of technical innovation in palaeognaths before our study, and there was a prevailing view that they are 'dumb' birds.
"Our research suggests that is not true and that technical innovation may have evolved far earlier in birds than previously thought."
The team now plan on conducting more cognitive research on palaeognath birds. For fair comparison, the rotary task needs to be rolled out to other bird species to assess how they respond to the same problems, and how they try and solve them.
"The more we study palaeognath birds, the more we can understand the broader picture of bird cognition," concluded Dr Clark. "And because palaeognaths birds are the closest living relatives to dinosaurs, research might shed light on how dinosaurs behaved."
