Here is a problem: swans choose their partner for life. A Black Australian swan nicknamed Petra has fallen in love with a pedal boat, which looks like a swan. When winter came Petra stayed with boat rather than flying south. This could have been fatal for Petra when the cold weather arrived.

In the end though local zoo chiefs took pity on the swan and gave her and her boat boyfriend a place to spend the winter, and this week the pair were once again on the lake together. According to biologists in Muenster, northwestern Germany, Petra has been circling its plastic lover, staring endlessly at it and making crooning noises, all the typical signs of a swan in love.