Making the most out of a terrible situation — that’s how Dr. Matt Reudink describes his research into a mass mortality event of Vaux’s Swifts, an aerial insectivore that has experienced population declines throughout North America since the 1970s.
It is estimated that during the 2012 event, there were as many as 3,000 Vaux’s Swifts trapped in a residential chimney in Cumberland, BC. Unable to escape out of the top of the chimney, the homeowner created a tunnel using tarps, and opened up the bottom of the chimney to allow the birds to escape. While approximately half went free, the remainder perished; Reudink was contacted because of his experience with swifts, and asked if he could make use of the deceased birds for his research.
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The results, which published this week in The Condor: Ornithological Applications, found that the birds all came from the same two or three tropical wintering sites or habitats. According to the paper, “Patterns of migratory connectivity in Vaux’s Swifts at a northern migratory roost: A multi-isotope approach” bird breeding populations strongly connected to specific wintering areas may be more vulnerable to population declines, meaning this research has important implications for swift conservation.
To get these results Reudink and his research team, which included undergraduate Lauren Steele and graduate student Andrew Pillar, randomly sampled 98 birds, measuring each and taking a small sample from the tip of the claw for isotope analysis. Pillar then spent a week completing the stable isotope analysis at the Smithsonian Institution in Washington, D.C.
Proportions of isotopes of hydrogen, carbon and nitrogen in birds’ bodies can tell researchers where they have been, because isotopes in bird tissue are determined by the isotopes found in whatever the bird has been eating or drinking in nature. The research shows “a moderate level of connectivity” in the wintering grounds, and acts as a springboard to conduct other research and answer other questions about this under-studied bird.
“Most of the aerial insectivores are declining, and it’s been very perplexing. Why are all these different birds experiencing population declines? They live in different habitats and in different parts of the country and different parts of North America. We’re trying to get at the root causes, but we really know very little about these birds and about most migratory birds in general throughout their annual cycle,” said Reudink.
More information
Dr. Matt Reudink
mreudink@tru.ca
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