Although it is possible in principle to use a compass for this task, the directional information that is required to maintain a heading need not involve any absolute geographical reference at all.
Moreover, that anosmic birds did not differ from controls in their track straightness indicates that anosmic birds' ability to maintain a heading, most probably by reference to a compass36, also remained intact.
"All they have to do is to maintain a heading relative to that landmark and they'll be OK," he says.
But to these two steps we should perhaps add a third, in which directional information is used to maintain a heading that has been set, without updating that course on the basis of some updated estimate of position relative to home.
To put this in perspective, at a cruising speed of 60 km/h, and in the absence of any wind, a homing pigeon maintaining a constant heading with respect to the sun would fly a circular arc of radius 229 km.
One way is by giving it to Burton, who has long maintained a head-turning aplomb as he presents each new theatrical entertainment.
Here we investigated whether tactile information from the feet can be used as a (partial) substitute for vision in maintaining a stable heading direction.
Migrating monarchs rely on the sun to maintain a constant heading.
First, a flying animal might use the sun to maintain a constant heading towards a target with which it is not in sensory contact.
Daldry, though, is maintaining a level head.
But the incident, and our panic, showed me how important planning is to maintaining a clear head.
