Sydney, Oct 8 (Inditop.com) The amazing flight patterns and landing precision of birds rely on their ability to detect edges, scientists have discovered.
The research suggests that edge detection is crucial in helping all animals, including humans, move around safely, and may be more important than our ability to see colour.
The study by the Vision Centre and University of Queensland found that budgerigars ignore colour and look for the edge of an object in order to ensure a smooth landing.
This is the first study to reveal how budgies navigate from moment to moment and choose where they land, said Partha Bhagavatula, who completed the research as part of his PhD.
“It makes sense that birds use contrasting edges to target their landing. The edge of an object normally presents a good place to get a strong grip and it can help birds to avoid over or undershooting,” said Bhagavatula.
The findings have helped scientists understand how birds fly and land so accurately, particularly in dense spaces and low light, and also provide insight into human vision.
Bhagavatula and a team placed a feeder tray in the middle of a disc on a background of blue paper. Even though the food was in the centre of the disc, the birds landed on the edge and then walked to the middle.
“This showed that they were using the contrasting edge of the disc to guide a safe landing, instead of just setting down close to the food,” said Bhagavatula.
Different coloured disks were used under the same conditions, and although the budgies had the ability to differentiate among all the colours and the background, there were certain shades that they appeared to be unable to find the edge of. When these discs were used, the budgies landed anywhere.
“Birds can see in all three of the human primary colours – red, blue and green – and also ultraviolet, but their edge detection skills appear to be colour-blind,” said Bhagavatula, according to a Queenaland release.
“When birds are flying through dense foliage they may not be able to see much colour, as it is often in the low light of dawn or in the dark, but the contrast between edges is a fairly constant marker. It may be more practical for them to manoeuvre this way.”
The paper was published Wednesday in the October edition of PLoS ONE.
