For American birders, a winter trip to Sax Zim Bog in the Minnesota Northwoods west of Duluth is the natural history equivalent of the visit to Mecca. Midwinter sees some of the best chances in the US for Great Grey Owl, Northern Hawk Owl, Hoary Redpoll, Bohemian Waxwing and a host of other cold-weather specialties. Birding Sax Zim in spring and early summer isn’t quite the same tour de force, but it can be birdy with northern warblers like Connecticut, Nashville, Mourning and others, as well as Sharp-tailed Grouse.
But I came to Sax Zim this weekend with a different agenda: butterflies and odes, with a smattering of botany. The weather didn’t cooperate very well, with a strong cold front bringing torrential rain and a tornado risk yesterday, but the hours I did get in yielded some nice sightings — and provided a scouting trip for a return visit at midwinter! And of course if a breeding Great Grey Owl crossed my path, I wouldn’t mind that either.
Some of the usual suspects I’d seen earlier in the week with Beth at Crex Meadows also put in an appearance here: Canadian Swallowtail (in much larger numbers here), Arctic Skipper, a few very tattered American Ladies, and very fresh Hobomok Skipper. Monarchs were frankly almost abundant; one of the most numerous butterflies in the bog. I had tantalizing glimpses of what could have been bog-specialist fritillaries as I drove through the tamarack/black spruce bog, but they’ll have to wait until a return trip with more time to venture into the bog’s interior. Dreamy Duskywings were probing most of the colonies of a creamy white vetch along roadsides and trails, and on the extensive patch of white clover on a sand mine in the northern part of the bog.Two new northwoods butterflies did end up on my trip list, Pepper and Salt Skipper in good numbers along a productive snowmobile trail, and true Spring Azure (wisconsinbutterflies.org notes it as Celastrina ladon ladon, but on BAMONA it’s C. lucia). It’s a rather large species with very heavy spotting on the ventral hindwing and brilliant blue wings on the male.
My odes want list was very short: Ebony Boghaunter. There wasn’t nearly as much dragonfly action in Sax Zim as in Crex Meadows, but what dragonfly numbers there were, were dominated just the same by squadrons of baskettails. I spent most of the day Friday after my arrival looking for boghaunters in the deeper parts of Sax Zim without success — as elusive as Great Grey Owls. But just as the clouds piled in and put an early end to my day in the field yesterday, the last ray of sunshine tempted one very dark, almost solid black dragonfly to light on a patch of sand where I was watching some tiger beetles. And — as fate sometimes would have it — there was my Ebony Boghaunter.And speaking of tiger beetles, the sandy terrain that underpins the bog provides a perfect habitat for a number of interesting species, although all I saw in my brief window of sunshine yesterday morning were two species that occur also in Maryland — Cow Path Tiger Beetle (Cicindela purpurea) and Oblique-lined Tiger Beetle (C. tranquebarica). Both were abundant on the afore-mentioned sand mine spoils, allowing even a so-so photog like myself to snap a few pictures (and even to get a short video of a female Cow Path Tiger Beetle digging and ovipositing in a shallow hole in damp sand).
No trip to Sax Zim would be complete without a stop at the one local eatery — The Wilbert Cafe in Cotton, MN — where I whiled away a couple of the worst hours of rain using their WiFi hotspot. As is the way of many of our local mid-Atlantic LepLunches, the Wilbert is a truly unprepossessing spot with very good food, in this case a double hamburger with cream cheese and green olives, followed by an amazing rhubarb sour cream crumble pie.