Lessons from a mayfly

Recently I attended the Aldo Leopold Chapter of Trout Unlimited fundraiser. This chapter's leadership was essential in enabling Groundswell Conservancy to purchase 40 acres on Dell Creek in Sauk County. The Dell Creek watershed has the chance to become a stronghold for wild brook trout and much of the 40 acres is excellent bird habitat in the form of healthy oak woods.

TU fundraisers, like those for many hunting and fishing organizations, consist of auctions and raffles, with a favorite being the bucket raffle. Lots of buckets paired with great prizes; attendees choose the prizes they want to win by putting their tickets in the appropriate buckets.

Mayfly, photo by Aaron Carlson FCC

Since I don't tie flies and since TU chapters always have some highly skilled tyers donate some great collections, that's what I try to win: a truly lovely collection of flies by a member of the Leopold Chapter. I paused, though, when I realized most of the flies imitated the gorgeous mayflies that used to inhabit southern Wisconsin streams. You probably noticed that sad word, "used." They don't anymore and I realized I'd never use those flies.  

A nearby bucket offered a prized bourbon as the prize. There went my tickets and I won!

You're probably wondering by now, what is the connection between that whiskey and Cedar Waxwings? In my last blog, a Cedar Waxwing, my favorite bird, is photographed eating a serviceberry. That's the characteristic pose of the fruit-loving beauty. I have a different favorite image of the Cedar Waxwing. For much of the summer, small flocks of Cedar Waxwings gather in trees along trout streams. They wait to feed on mayflies that have hatched from the stream and are flying into streamside vegetation before they return to the waters to mate and lay eggs.

The waxwings then fly with amazing agility as they hover, turn, and swoop to catch the mayflies. I fear this cherished and anticipated sight will become a memory. 

Cedar Waxwing, photo by Kelly Colgan Azar

Science is just beginning to quantify, document, and analyze what trout anglers in southern Wisconsin and elsewhere around the country have noticed for years; many species of mayflies have disappeared or vanished. Anglers and the myriad birds and bats that gathered at Black Earth Creek for the spectacular hatch of Hexigenia limbata, our largest mayfly, wait in vain or don't bother. You might remember old magazine covers or sporting art that showed trout leaping out of the water to catch a flying mayfly. That used to really happen (I saw it frequently and it was always a thrill) and the mayfly was probably the Hendrickson. It too is just about gone from southern Wisconsin streams.

We don't know with any certainty much about these losses. From a bird lover's perspective, I don't know how much harm the loss of such abundant, seasonal protein means to birds such as swallows and Cedar Waxwings that feed heavily on the hatches. Since some of the hatches occur in the late afternoon or early evening I'm not even sure if we know which birds focused on those hatches. A friend has asked anglers on Black Earth Creek to participate in a survey on Hexagenia limbata. From the few and early reports I've seen the results are discouraging.

One signal for anglers around here that the hexagenia would be hatching would hover over one's lawn in the evening: lightening bugs, on everyone's Top Ten list of favorite insects. I just had the sad realization that I have not seen a single lightening bug this summer. And don't even ask about monarchs. We have a lot of work to do.

We also don't know why the flies are disappearing. The neonicotinoid pesticides which seem to be devastating many pollinator species are prime suspects. The Wisconsin DNR is beginning to research this possibility. The problems with these pesticides are many: they're highly toxic to a variety of insects, they persist, they easily move from plants and soil to the water, and they are everywhere one finds commercial agriculture. As of last year, just about all of the field corn and soybean seeds sold in Wisconsin were treated with neonics. For some of the key crops, the neonics have left the plants and entered the environment before they affected the targeted pests. As a result they did not improve farmers' yields.

I have noted that my friends who fish the northern Wisconsin streams where commercial agriculture is much less prevalent or absent still witness the mayflies we no longer see.

American Kestrel eating a grasshopper, photo by Gary Leavens FCC

By the way, the problem probably extends beyond pollinators and aquatic insects. The New York Times published a long report on the decline of kestrels. Young kestrels aren’t skilled enough to hunt the bigger prey of the adults (little birds and mammals, for example) and need easier prey. Grasshoppers might be a key food and they too are vulnerable to neonics.

From an advocacy perspective, the first course of action is to accelerate research. The real work will come if neonics should be subject to more thorough and careful regulation in order to protect bugs and birds. This might be our generation's version of the battle that conservationists waged against DDT. If so, we'd better have the gumption and persistence they demonstrated.

Take care,

Topf Wells, advocacy committee