on the edge

Tromping around Weaver Dunes, south of Wabasha MN, for 8 hours trying to identify every bird we could find was exhausting but rewarding, and what an absolutely beautiful day to participate in The Nature Conservancy’s bird blitz on May 12.

Cape May Warbler-

First bird of the day — Cape May Warbler, high in a leafy tree (bane of photographers — the tree, not the bird)

The spring migration was running a little behind schedule, but we managed to find (and identify) 58 species (which admittedly doesn’t sound like a lot for 8 hours of work).  We explored a variety of habitats, but the best places to look were edges between shrub and forest, or prairie and forest.

Yellowrump Warbler-

Yellow-rumped Warblers outnumbered other warbler species, and thankfully posed at much lower elevations in the trees.

Rose-breasted Grosbeak-

We only saw one Rose-breasted Grosbeak, and he was quite shy about coming out in the open to show off his raspberry bib.

Lark Sparrow

Lark Sparrows were more common than the warblers, flashing their white outer tail feathers as they flew. True to their name, their song is much more of a warble than a buzz — i.e., lark-like.

Lark Sparrow

Lark Sparrows typically nest in shrubs and forage in grassy areas removed from the nest. They have the unusual habit of walking, instead of hopping.

Northern Waterthrush-

Down at the edge of a small pond, a Northern Waterthrush hunted for insects.

Northern Waterthrush-

A distinctive eyestripe and wagging tail made this large warbler easy to identify.

Brown Thrasher-

A Brown Thasher was very uncooperative about posing, and remained hidden in the dense foliage of trees in the grassy savannah.

Baltimore Oriole-

Orioles foraged high in leafy treetops, but were easy to find by listening for their characteristic song.

Gray-cheeked Thrush-

Another edge-lover found skulking among the low vegetation in the woods surrounding a pond was the Gray-cheeked Thrush, with its characteristic white eyering.

Our efforts were added to those of the birders walking other TNC properties throughout the tri-state region of MN, North Dakota, and South Dakota.  Together all observers on May 12 found over 200 different bird species, or approximately 50% of those known to reside or pass through MN on migration in May.  Not bad…it’s a nationwide competition, so we’ll see how MN bird numbers stack up with those elsewhere in the U.S.

Considering that our American birds have to navigate and survive stormy weather and drastic climate changes, glass windows and glass-covered buildings, marked habitat alterations, and depleted food supplies from all the pesticide and herbicide applications, it’s a wonder that we see the diversity that we do.

Prairie scenes

Fall color in central Minnesota farm country is a little past its peak, but is still colorful on a warm autumn day.

Ordway Prairie, MN

Ordway Prairie, a Nature Conservancy preserve near Starbuck MN shows off its mix of upland prairie (bottom left), lowland wet meadows with cattails and Phragmites reeds, and interspersed woodlands of aspen and oaks.

sheepberry fen-

A few yearling steers gallop around the corner of their pasture to return to the safety of the rest of their herd grazing on pasture at TNC’s Sheepberry Fen preserve.

sheepberry fen-big bluestem

Big Bluestem (center) and the other grasses of the native prairie have taken on their russet-colored autumnal hues and dangle seeds to be carried off by the wind.

pothole lake in sheepberry fen

The water was so still in this prairie pothole lake, it provided a perfect mirror reflection of the landscape.  Click on the image to get a larger view of this amazing reflection.

sheepberry fen-prairie pothole lake-

These prairie pothole lakes are important breeding sites for waterfowl in the summer, and a few of the more productive ones support migratory birds that stop over on their way south in the fall.

BioBlitz at Sheepberry Fen

It’s amazing how much more you can see when a dozen pairs of eyes are looking. We drove out to the central Minnesota prairie early yesterday morning to participate in a BioBlitz event organized by the Land Stewardship Project — i.e., walk the prairie and record as many species as you can find.

Sheepberry Fen, near Glenwood, MN

Although we originally split up into a bird team and a plant team, we ended up recording everything we saw, which included a few more flowering plant species (47) than bird species (31).

We had driven by The Nature Conservancy’s Sheepberry Fen property several times, but never walked it.  In addition to the rarer plant and animal species that occur there, the area features a collection of calcareous fens fed by alkaline (high calcium and magnesium) ground water.

The weather looked ominous, with a giant storm front parked over central Minnesota, but it didn’t start raining until we had walked around for three hours and were eating lunch under cover.

Red cedar on the prairie at Sheepberry Fen, MN

The prairie was burned this spring to control invasive Red Cedar and other woody species, but was only partially successful as indicated by the dead lower branches of the larger trees in the foreground.  Many of the spring blooming perennials were set back and were still flowering, just as the summer blooming species were starting.

Most of the birds were spotted from afar as they flew over us or perched in remote trees.  Even on a dreary, cool morning, the birds were pretty active, if not highly visible nearby.  However, the insects were mostly absent:  a few Halloween Penant dragonflies and one Widow Skimmer comprised my entire species list for that group.  We saw one or two Monarch butterflies (there were at least three species of milkweed blooming in our patch of the prairie), a couple of small unidentified skippers, a few flies (no mosquitoes were even out to “bug” us), and just a couple of bees.

However, we did see a few other unusual species that would not have been obvious without the help of those dozen pair of eyes, studying the ground as we walked.

A mound of Thatching Ants at Sheepberry Fen, MN

A mound of Thatching Ants, about 18 inches high and 2-3 feet across stuck up out of the prairie floor.  This relatively large-bodied ant can form “supercolonies” that are connected below ground.  One such supercolony found in Oregon contained 251 nests and over 56 million ants!

Thatching ant, Formica obscuripes

A closer view reveals at least two castes (red-headed and black-headed) working on the top of the mound.  I might entitle this photo “organized chaos”, but these ants have a system for adding vegetation they collect from around the mound to build it even higher.

Thatching Ants (Formica obscuripes) build their mounds in the sandy soils of arid scrub, old fields, and prairies, but they forage widely to feed on insects and milk the honeydew of aphids that they tend on plants near the mound.  Through solar radiation and the heat provided by decomposing vegetation, the mound remains warm during the cooler months, and ants remain active repairing and adding to it.  Some have lasted up to 40 years and reach a meter in height.

Soldier Fly, Odontomyia cincta, on whorled milkweed

A Soldier Fly (Odontomyia cincta) was spotted on a tiny Whorled Milkweed plant.  Its distinctive green and black body and huge brown eyes made it easy to determine its identity with the help of BugGuide.net.

Soldier Fly, Odontomyia cincta, on whorled milkweed flower

The soldier fly appeared to be almost comatose on this cool morning. Normally these flies feed on flower nectar as adults, so they might be good pollinators of prairie plants.  They lay their eggs near the shores of slow-moving water (like a fen), where their larvae feed on pond algae and are important food sources for other aquatic invertebrates like dragonfly naiads.

Millipede, possibly Pleuronema flaviceps, at Sheepberry Fen prairie

When you’re looking at tiny plants, sometimes you find tiny animals, like this prairie millipede.  About an inch long with double sets of legs in each segment, he was scurrying along.  According to BugGuide, this might be the species (Pleuroloma flavipes) that herds its young in huge densities through forest litter.

Sharp eyes detected movement in the crack of a rock, and we found a Prairie Skink (Plestiodon septentrionalis) hiding there.

Prairie Skin, Plestiodon septentrianalis at Sheepberry Fen prairie, MN

We were lucky to see this guy (gal?), because they are quite secretive and usually not seen in the open.  During the breeding season, males sport an orange throat, so perhaps this is a female.

Skinks have very smooth scales and look shiny.  They tend to lose their tails rather easily when snatched by a predator, and the tail keeps wiggling after it is detached, so the predator concentrates on that rather than the skink itself.

Prairie Skink, Plestiodon septentrionalis, at Sheepberry Fen prairie, MN

Their shovel-shaped snout helps them dig a deep burrow where they can take refuge or where they might hibernate from September to April, below the frost line.

BioBlitz is a great way to learn a great deal more about a particular place, and meet a few new friends along the way.