Robins start with a magnetic compass in both eyes, and end up with just one

Here’s an amazing fact: Adult robins have a magnetic compass in their right eye that allows them to sense the direction of the Earth’s magnetic field, and navigate when all other landmarks are obscured. Here’s an even more amazing fact: Baby robins have two such compasses, one in each eye. They lose the left one as they grow up.

Robins kick-started the study of magnetic senses in the first place. In the 1950s, a German biologist called Hans Fromme showed that robins would always try to escape from a cage in the same direction when it came time to migrate. Even though they had no visual bearings, they headed south-west, as if sunny Spain lay just beyond their cages. In 1966, the husband and wife team of Wolfgang and Roswitha Wiltschko showed that a powerful magnet could disrupt this constant vector, sending them skittering in all sorts of directions.

Lees meer: Not Exactly Rocket Science

Cuckoo Tricks to Beat the Neighborhood Watch

To minimise the chance of being recognised and thus attacked by the birds they are trying to parasitize, female cuckoos have evolved different guises. The new research, funded by the Natural Environment Research Council, was published August 3, in the journal Science.

The common cuckoo (Cuculus canorus) lays its eggs in the nests of other birds. On hatching, the young cuckoo ejects the host's eggs and chicks from the nest, so the hosts end up raising a cuckoo chick rather than a brood of their own. To fight back, reed warblers (a common host across Europe) have a first line of defence: they attack, or 'mob', the female cuckoo, which reduces the chance that their nest is parasitized.

Lees meer: ScienceDaily