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Monitoring Monarch migration at the Mackinac Straits

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Newsletter of the Michigan Entomological Society. 65(1): 2-5.


An active group of expert birders have been monitoring spring and fall raptor migration across the Mackinac Straits for the past several years. These birders are members of Mackinac Straits Raptor Watch (MSRW;, a nonprofit group dedicated to the research and conservation of raptors in the Straits of Mackinac. Nearly daily spring counts started in 2012 near the tip of Michigan's Lower Peninsula in Mackinaw City, and nearly daily fall counts struted in 2018 in the Upper Peninsula (UP) at Point LaBarbe, which is less than 2 miles west of where the Mackinac Bridge links to the UP near St. Ignace (see map; N 45.8397, W -84.7550). Point LaBarbe is a relatively flat and open site with mostly small trees. About 3.5 miles of open water separates Point LaBarbe from the nearest land at the northern tip of Michigan's Lower Peninsula. Spring counts usually start in late February and end in early June. Fall counts typically start in late August and end in November. In addition to raptors, the birders who first evaluated the UP site at Point LaBarbe in 2017 also noticed large numbers of monarch butterflies (Danaus plexippus L). Therefore, when the official fall raptor counts started in 2018, daily counts of monarchs were also recorded.


monarch; Lepidoptera; Michigan; butterfly migration


Haack, Robert A. 2021. Monitoring Monarch migration at the Mackinac Straits. Newsletter of the Michigan Entomological Society. 65(1): 2-5.

Last updated on: March 23, 2021