Laura Erickson's For the Birds

Sunday, March 8, 2015

Fishicles

A Strange Sight
Photo copyright 2015 by Kelly Preheim

This winter has been colder than average over much of the Great Lakes—the ice cover over the Great Lakes system was at 88.3 percent as of March 1, and 94.1 percent of Lake Superior is ice-covered.

Here at the western end of the big lake, we can usually still see a big patch of open water, though that moves from day to day. The ice piles up on the South Shore when winds have a northern component, and on our side of the lake when winds are southerly, so our hopes of spring, pinned to that blue water, can be raised or dashed depending on which way the wind is blowing. Hamlet must have lived on the South Shore to be but mad north-northwest.

As the ice sheets slosh back and forth, colliding with the shore and other ice sheets, dead fish and other small aquatic critters at the surface end up getting embedded in the ice. By March and April, we see increasing numbers of crows, ravens, and eagles walking on the ice. When people ask me what they’re looking for, I explain about these frozen dinners, but I’ve never had a good photo of what’s happening, until I heard from Kelly Preheim, a kindergarten teacher and birder from South Dakota.

On February 28, Kelly wrote in her wonderful BirdTeach blog:
The lake at Lake Andes National Wildlife Refuge had a fish kill last year and in mid-March there were hundreds of Bald Eagles, American Crows and gulls at the lake in a feeding frenzy! It was quite loud amongst the flurry of wings and I was amazed at what I saw! This year is proving to be a repeat year. Today there were deceased fish scattered all along the surface with some fish in these vertical ice jams.
A Strange Sight
Photo copyright 2015 by Kelly Preheim
Kelly posted this amazing photo of fish trapped in the ice, and gave me permission to use it here. Apparently wind and wave action had pushed some ice sheets into a vertical position, and fish that had been trapped—probably dead on their sides when originally frozen—were propped up and appeared to be jumping—some looking quite alive within the ice sheet. She also added a photo of an eagle on the ice.

Fish Buffet
Photo copyright 2015 by Kelly Preheim
I’ve never ever seen anything so dramatic on Lake Superior. The oligotrophic nature of the lake—that is, its high oxygen content and low density of plankton and vegetation—and its sheer size, keep concentrations of fish down. Sure enough, the birds we see combing the ice aren’t nearly as concentrated on the lake as they are in Allouez Bay off Wisconsin Point, and even there I've never seen anything like what Kelly documented in South Dakota. She posted another photo to show how many eagles were gathered nearby.

Photo copyright 2015 by Kelly Preheim
Even if we can’t see the fish from shore in my neck of the woods in anything like Kelly's surreal photos, experienced birds know that fish are there, and even inexperienced ones discover them either by spotting them as they fly over or by noticing other birds picking away.  I’ve never flown over the lake myself, so I can’t be certain, but I’m sure there are both insects and fish, some mostly intact and some in bits and pieces sitting out there waiting to be eaten.

Up here in the north, ice sometimes remain in Lake Superior until May and some pockets close to the lake may not have much leaf out before June, so signs of spring can be subtle and easy to miss. Even our fish kills are apparently not as dramatic as they are in other places. Watching crows and eagles combing the decaying ice surface for bits of dead aquatic animals may not appeal to some people, but I’ll take the season as it comes.

You can learn more about Kelly Preheim's adventures with her students at Kelly's delightful  Kindergarteners on the Go! blog. And check out the Destination Nature facebook page and Kelly's flickr photostream:

https://www.facebook.com/DestinationNature

No comments :

Post a Comment