Monday, July 1, 2013

Cambridge Bank Swallow Colony

While we were doing our breeding bird survey ("BBS") route last week we noticed at one of our stops that there was a steady stream of Bank Swallows going back and forth across the road. We were in the middle of a 50 station survey, so we didn't have time to investigate, but we returned today to search the area.

We found the colony in no time. There were approximately 200 nest cavities excavated out of the sand bank. As well, we estimated 200+ Bank Swallows circling and foraging overhead.

The birds were quite nervous at our presence. When we approached too close, the nestlings retreated deep into the nest crevices where they were not visible and the adults would not enter the nest cavities. We had to maintain a distance of about 50 metres before the birds returned to normal.

According to BBS data, populations of Bank Swallows have declined significantly in Ontario in the past 40 years. Federal and provincial government committees continue to debate whether or not these birds should be deemed to be "at risk". In the meantime, Bird Studies Canada and some of its partners have initiated the Ontario Bank Swallow Project to document the locations and characteristics of Bank Swallow colonies and roosting sites.

Bank Swallow is a cosmopolitan taxon, and is known by Europeans as the "Sand Martin" (though some eager taxonomist could probably make a case for splitting the North American population into a separate species). On a worldwide scale Bank Swallows are abundant and not considered to be a conservation concern.

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