Jim and others:
Just to be clear, the study by Koenig and Liebhold does conclude that most of the species examined experienced significant population increases during the year after the 17-year Cicada irruption. This conclusion makes sense, since the benefit of high food abundance would result in high brood numbers and overall reproductive success, which would be detected in subsequent years.
But the question of cicada cycles being timed with those of avian populations is an interesting one, and worth further exploration. Thanks for sharing, Jim.
For those who are interested, the original article was published back in the July 2005 issue of Ecology. The full citation is:
Koenig, Walter D., and Andrew M. Liebhold. 2005. EFFECTS OF PERIODICAL CICADA EMERGENCES ON ABUNDANCE AND SYNCHRONY OF AVIAN POPULATIONS. Ecology 86:1873–1882. [doi:10.1890/04-1175]
Ross GeredienEdgewater, MD
--- On Fri, 5/20/11, Jim Wilson <> wrote:
From: Jim Wilson <>
Subject: Re: [MDOSPREY] 13-year Cicada update
To:
Date: Friday, May 20, 2011, 10:32 AM
The Spring 2011 Cornell Birdscope Newsletter has an interesting short piece about birds and the 17 year cicadas. The info is very counterintuitive. I quote:
" Koening's research team found, using data from the Breeding bird Survey and Christmas Bird Count, that many insectivorous birds declined in numbers during the 1987 and 2004 emergences of the "Great Eastern Brood," another population with a 17 year cycle. Of the 24 species they investigated, they found that only 2 species, the Yellow-billed Cuckoo and Black-billed Cuckoos, increased during cicada emergences, while 16 decreased.
... It looks like the cicadas are somehow engineering the bird population by their cyclic life-history to be less common when emergences take place, reducing predation pressure. The mechanism behind this is obscure, but the fact remains that this provides a glimmer of an ecological explanation for why there might be 13 and 17 year cycles."
Jim Wilson
Queenstown
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