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Jon McCracken, program manager at Bird Studies Canada in Port Rowan, documents the decline in the most recent issue of BirdWatch Canada. In the article, McCracken examines possible explanations for the increasing scarcity of common, beloved species such as swifts, swallows, martins, flycatchers and whip-poor-wills. McCracken concludes that we should find answers to this mystery sooner rather than later. "There are a whole lot of question marks out there," McCracken said during a telephone interview. "That's what's got our attention. We feel time is of the essence."
"Aerial insectivores" belong to a "guild" of birds that feed on flying insects. Patterns of decline have been documented in recent years in the Breeding Bird Survey and the Ontario Breeding Bird Atlas. In some cases, the decline is continent-wide and not just in Ontario.
In his article, McCracken suggests population reductions may be related to changes in the food supply. However, insufficient data is available to assess the state of the flying insect population. Key members include moths, butterflies, dragon flies, damsel flies, midge flies, bees, wasps and hornets.
Any number of factors could be in play. Suspects include climate change, the widespread use of pesticides in agricultural areas, changes in ultra-violet light from the sun, and increasing light pollution in expanding urban areas.
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http://www.brantfordexpositor.ca/ArticleDisplay.aspx?e=934752