Tally of  the  bog

More than 900 species of animals and plants have been found, identified and counted on 300 square miles of land near Cotton, Minn., northwest of Duluth.

That's just the beginning of the tally.

This mix of Aspen upland, spruce and tamarack forest, meadows, old hayfields, bogs, lakes, rivers, farms and towns contains what birders know as the Sax-Zim Bog.

The bog has been an important birding destination for many years, particularly in wintertime.

It's an excellent example of biodiversity — the wide range of living things animal and vegetable for which preservation is so important.

Sparky Stensaas and Clinton Nienhaus manage an annual counting and educational event known as the BioBlitz. Stensaas told me he believes the potential number of life forms for the count area exceeds 2,000.

The fourth annual BioBlitz took place in July with more than 40 participants, many from the support group Friends of the Bog. Included were several experts in various species categories.

"For example, August is better for spiders and fungi, while June is much better for orchids and birds," he said.

A total of 374 species were found this year. Ninety were new to the composite list.

Just how diverse in this land? The species list for the day included 16 different trees and shrubs, four different reptiles and amphibians, 10 mammal species, 23 moths, 22 dragonflies, 90 wildflowers, 28 grasses, five fish, 28 butterflies, one crustacean, 27 spiders, four lichen, seven ferns, eight culbmosses, two mosses, two horsetails, one grape fern, three bumblebees, two ladybird beetles and four other insect species.

Highlights of this year's count, Stensaas said, included a bobcat, two new fish species, the butterflies, the dragonflies, and an estimated 100,000 Northern yellow-eyed grass plants, a species of special concern in the state.

"We've counted all the regular bird species [85], and many of the wildflowers," Stensaas said in an interview.

Over 23,000 acres of the area are preserved as a wetland bank. Friends of the Bog owns 326 acres. There also are several state wildlife management areas.

Stensaas said there is concern about lowland black spruce and tamarack logging. "The rotation on this type of forest is 80 to 100 years," he said, "and sometimes it doesn't grow back to spruce-tamarack."

The BioBlitz is a chance to get experts into the bog to help build the master list of species, Stensaas said. It's also just plain fun, he said.

Sax-Zim is famous throughout North America because of its birds, many of them boreal specialists most easily seen in winter. The town of Meadowlands, on the bog's edge, holds a well-attended annual winter bird festival (Feb. 17-19, 2017, saxzimbirdingfestival.com).

It is believed to be North America's only such festival held in what we regard as winter.

Read Jim Williams' birding blog at startribune.com/wingnut.