Drongos and Cuckoos

The Kalahari Desert appears to be an inhospitable place, but it’s prime real estate if you’re a meerkat. Hot in the day and cold at night is the typical desert weather. The mornings tend to be slow as everything warms up and the meerkats stand up to let the sun warm their chests, in that typical pose seen so often on posters. They dig around for insects but also munch on lizards and scorpions for lunch. With your head in the ground you’re a prime target for predators like hawks, so the troop has sentries standing guard who call a warning if one is seen and then they all dash for cover.

The fork-tailed drongo bird doesn’t have to time or inclination to go digging around, so it just mimics the meerkat alarm and pops down to steal their lunch. Flower from U of Cambridge has published the final version of his study of this sharp practice (1). The dreaded drongos are sharp enough to toss in a few genuine hawk alarms to maintain their credibility. If the meerkats aren’t working hard enough for the drongos, they are not beyond scaring the pied babblers and stealing their lunch instead.

Mimicry of a different order is the annual practice of cuckoos. Spottiswoode and Stevens from U of Cambridge (2) have recorded a defense being developed by some warblers against the cuckoo finch. Very discriminating species may spot slight differences in the cuckoo’s egg compared to their own. Not all warblers are that capable as the cuckoos are pretty capable mimics.

The latest defense strategy has been to lay lots of different colored and patterned eggs so the cuckoo’s egg is way out of fashion and stands out like last years design at a fashion show. The “oh so yesterday’s” egg is then pierced and kicked out. A high price for being unfashionable.

  1. T.Flower, Proc. R. Soc. B May 22, 2011 278:1548-1555
  2. http://rspb.royalsocietypublishing.org/content/early/2011/04/05/rspb.2011.0401.full?sid=1ea23cb9-f497-4607-8183-4f7911b4b548

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