As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Thursday 21 March 2013

Deus ex Cicada: Are Predatory Bird Populations Influenced by Cicadas’ Odd Life Cycles?

Bird population crashes seem to correlate with the strange 13-year and 17-year cycles of periodical cicadas. Some researchers suggest that the dissonant insects actually orchestrate the behavior of their predators

As the first day of spring approaches a scientific mystery will soon return with a roar— the 2013 return of the east coast brood of cicadas, or Brood II. Now a team of scientists hint they may have a solution as to why this brood and its fellows bizarrely emerge only after lulls more than a decade long—to control their surroundings in ways that may lead to crashes in numbers of predatory birds.

Magicicada septendecim
Periodical cicadas are the longest-lived insects known. After childhoods spent underground living off the juices of tree roots, broods of red-eyed adults surface in precise cycles— 13 years long in the southeastern U.S. and 17 years long in the northeastern part of the country. Fifteen broods are known to exist today on Earth, all native to North America. Brood II is set to emerge this spring in New York State, Connecticut, Maryland, North Carolina, New Jersey, Pennsylvania and Virginia with choruses of males bent on wooing mates with their din. It remains an enigma why these cicadas only emerge together in the adult stage every 13 or 17 years, as opposed to some other duration — other cicada species are not so synchronized.


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