Mites hitch lift in birds’ beaks

Eastern Spinebill Credit: Rohan Clarke, Wildlife Images
Eastern Spinebill. Credit: Rohan Clarke, Wildlife Images

Nectar-eating Australian birds make clever choices about which flowers to raid. And so do the flower mites which hitch a ride in their nasal passages, according to zoologists Jolene Scoble and Assoc. Prof. Michael Clarke at La Trobe University in Melbourne.

During winter, eastern spinebills are particularly dependent on nectar from the mountain correa, a shrub which flowers over several months. During this time, a single bush may display hundreds of flowers at different stages of development.

Jolene and Michael showed the birds did not feed at random. Rather, they selected flowers at the peak of their nectar production. What’s more, they avoided flowers which displayed a split or tear showing they had previously been visited by other nectar feeders, such as silvereyes. Just what flower features acted as a cue to attract the spinebills is the subject of future studies.

The spinebills were not deterred from feeding by the presence of another nectar robber—flower mites. In fact, Michael says, the mites travel from flower to flower by crawling into the nasal passages of the bird. “By choosing when to climb on or off the bill, the mite is also choosing where to feed.”

For more information: Zoology Department, La Trobe University, Michael Clarke, Tel: +61 (3) 9479 2244, m.clarke@latrobe.edu.au