Isle Royale & black flies

A friend and I are planning on going to Isle Royale in May. For those if you who have been there in the spring, when do the black flies usually hatch and become a problem there. We plan to paddle the south shore from Rock Harbor and portage into Siskiwit and Wood lakes.

Watch the temps in the region
Typically the black flies show up in Michigan’s Upper Peninsula around the Lake Superior shoreline mid-May through mid-June. This is, however, dependent upon how much warm weather hits, as this is what causes the hatch. Note that being at a slightly more northern latitude, Isle Royale may be as much as a week later than the U.P.

Last year during the first week of May I backpacked the Pictured Rocks with a buddy of mine. The first day was fine: temps in the mid 50’s to low 60’s. The second day, however, we saw an unusual 85 degrees and every black fly in the area hatched with miserable results.

Be prepared with a head net and lots of cigars, and try to camp on a breezy point if possible. And watch the south shore on the day you paddle from Rock Harbor light to Chippewa Harbor and to a lesser extent, from Chippewa Harbor to Malone Bay–the shore is rocky and steeply sloped into the lake and it will be difficult to find a suitable landing spot if you have southerly winds.

Good luck and have fun!


Blackfles in May
Years ago, a buddy and I went back packing on Isle Royale, starting on opening day (mid May). There were plenty of mosquitos but no blackflies. At the time, we heard blackflies became more of a problem in June.

late spring
It’s been a late, late spring, so chances are you’ll be fine. But just call and ask the rangers before you head up–they have great rangers up there (you might get one of my grad students!)

June is usually the bad month.