Sunday, December 23, 2007

Butcher birds seek larder in Ohio

We find a Northern Shrike (Lanius excubitor) on Delaware Wildlife Area, Delaware County, central Ohio, and we comment on unusually frequent sightings in Ohio this winter.

A Northern Shrike (a.k.a. butcher bird), rare Ohio visitor, on the lookout for rodents and small birds, Delaware Wildlife Area, central Ohio.

See a beautiful closeup photo of a Northern Shrike at Michael McDowell's Birding and Digiscoping blog.

Northern Shrikes typically perch atop twigs reaching skyward from small trees and tall shrubs along shrubby edges and roadsides. They are rare visitors in Ohio; solitary sentinels keeping watch over our wintry old fields. During most years birders find very few Northern Shrikes in Ohio and these are usually found in counties near Ohio's northern coast along Lake Erie.

Typical Ohio winter shrike habitat mimics the vegetative structure of taiga openings: An elevated perch overlooks accessible thick turf and duff supporting abundant rodents. Note the shrike on uppermost branch of tree, at center.

Shrikes hunt from their perch, and they perch where they can see prey. During their southerly sojourns they find that they see well from roadside utility wires, too. Roadsides hold small mammals and birds starved for habitat and desiring roadside minerals or grit.

Their descriptive Latin name "Lanius excubitor" is translated "butcher watchman," a perfect description. Shrikes are skilled passerine predators with voracious appetites for small mammals and birds, especially during winter. Their large heads and muscular necks power their raptor-like hooked bills through the spine of their prey, sometimes leaving their prey alive but unable to muster a response.

A full belly will not tame this aggressive hunter. Like humans, shrikes kill more than they eat, collecting their prey like trophies on display in their thorny larder, in cold storage for a snowy day. Their larder might be found in a honeylocust tree festooned with branchy spines that serve nicely as meat hooks; and meat hooks they are: Shrikes impale mice, voles, shrews, and small birds, dead or alive, on thorns and spines, and even on barbed wire. Their larders serve them well during lean times such as when rodents remain hidden under crusted snow!

This is an exceptional winter for shrike sightings, and predictably so. Northern Shrikes are irruptive: Their southerly occurrences cycle with rodent populations in their northerly range where taiga meets tundra, and wherever the taiga canopy opens to let the Northern Lights cast their electric glow on grassy turf and undergrowth.

Rodents are scarce in the far north this winter. Speaking of food availability and owls in his winter forecast (September, 2007), Ron Pittaway of the Ontario Field Ornithologists predicted good movements of northern owls in response to plummeting rodent numbers. Ron didn't mention Northern Shrikes but I'm sure the same reasoning works for them.

"Small mammal populations were abundant this summer in northern Ontario, presumably increasing after the big seed/berry/fruit crops in 2006. However, crops this year are very poor in much of the north, partly caused by cold weather and snow in late spring that froze the buds and flowers of many plants. . . . The huge population of deer mice in central Ontario is declining rapidly now because of poor seed crops this summer, particularly sugar maple samaras, which they store for the winter."

Some of Ontario's Northern Shrikes have wandered as far south as central Ohio this year, I think. No doubt, there is slim pickings up north; the rodent cycle has bottomed-out. That's good news for Ohioans because we find it a little easier to see these northern wonders when they come to our back-forty. There have been at least 26 sightings reported to the Ohio Birds Listserv since October (several, at least, are repeats of the same birds).

Saturday, December 8, 2007

Chasing birds and geology: Snow Buntings and Radnor kames

We look at glacial geology while chasing Snow Buntings and Lapland Longspurs, with mixed success, near the glacial kames* of Radnor, Ohio in northern Delaware County.

View of Radnor Cemetery gate where Radnor Road crosses the crest of a glacial kame.
Kames are glacial landforms, piles of sand and gravel left by water flowing on a glacier or leaving the glacier's ice margin. Pioneers often used glacial kames for burial because they are easy to dig. Fruit orchards were planted on kames because sand and gravel under shallow soils ensures good drainage. Professional aerial photo interpreters sometimes refer to cemeteries as "marble orchards" because these cultural practices were so common and widespread in the Midwest, and so easily seen when examining 3D stereo photo sets used in drafting topographic maps.
The Welsh "Lych" Gate to Radnor Cemetery was constructed in 1910 of locally quarried limestone, another geological resource influencing settlement patterns in central Ohio.

Wintertime is great for geologizing* landscape while chasing seasonal specialties--birds that occur in Ohio landscapes only seasonally. Absence of foliage opens our view to landscape and birds alike. Snow cover is not only pretty, it makes finding some of our bird species of open-field habitats a little easier. There's no better time than the first big snowfall of the season to explore new landscape.

Snow Buntings are a wintertime favorite of mine so a recent Ohio Birds Listserv post about Snow Buntings and Lapland Longspurs seen near Radnor, Ohio inspired me to chase them.

Snow cover makes these two species easier to see. They spend much more time along the roadside berm when their preferred bare farm fields are blanketed with snow. And it's easier to pick out longspurs and flocks of Horned Larks sitting still on distant dirt clods of plowed fields when background snow frames their silhouettes. Finding Horned Larks is the first step in chasing Snow Buntings.

Snow Buntings are occasionally found with larks and longspurs. It's fortunate they often hang-out together because Snow Buntings are cryptically colored: Perched atop small rocks in a vast farm field, they blend well with the snowy landscape. Their white, tan, and black patterned winter plumage hides them very well until they fly, flashing their broad white wing patches tipped with black.

I didn't find Snow Buntings this trip. I did find a half-dozen Lapland Longspurs and numerous small flocks of Horned Larks. As usual, they were uncooperative when I reached for the camera. The image below is of our more common Horned Larks.

Two Horned Larks seen here in typical habitat, farm fields.

Horned Larks are common in central Ohio farm fields in winter. They often gather in small flocks along the roadside when snow cover blankets fields. These larks were found along Price Road near Radnor, Ohio. Radnor Road and Hedely Road were productive drives as well.

Reasonable speculations. . .

I envision Snow Buntings as strongly associated with Ohio's pre-settlement prairie regions. They still occur most commonly in the lake plains and central till plains of Ohio where wet prairies once reigned. I think they follow ancient winter routes to the south, over Lake Erie and over the former Great Black Swamp country of northwest Ohio, taking them to former prairie country where snow blows less frequently and where bison once trammeled vegetation and moved snow, exposing wide swaths of prairie grass and bits of larval protein excavated by bison hooves. Today, buntings find open farm country along these ancient flight-paths, a habitat bonanza. Most Snow Buntings remain in the northwestern third of Ohio today. Scattered flocks of hundreds of wintering "snowflakes" may be found in the windswept fields of the lake plain some winters.

Imagine along with me a once wild Ohio where Snow Buntings follow bison to forage the seeds uncovered by their great snow-plow snouts, and to pick seeds from their dung. In the distance there is a band of Native Americans led by a sage hunter possessing the cherished natural wisdom of his clan. He sees a distant flash of white of Snow Bunting wings over tall Indian grass and pointing, whispers to his band, "There! Bison are there."

A little glacial geology. . .

A very brief Primer: Continental glaciations have sculpted Ohio at least four times during the last 1.6 million years (probably seven, but as many as seventeen glaciations may have sculpted Ohio but sediments from only four events survive). Ice covered much of the Northern Hemisphere during each ice-time, for many tens of thousands of years each ice-time, with comparatively brief intervals of ice-free warmth in between the ice-times; like the ice-free warmth we now enjoy. Ice sheets were thousands of feet thick. They spread and thinned toward their margins from thick accumulation areas toward their centers. They reworked the landscape by scraping-up material at their bases and conveying it toward their margins; more like conveyor-belts than like bulldozers. Along the way, low areas were filled-in with drift and highs were scraped and flattened.

What's what: Drift is a general term for anything carried and deposited by glacial processes. The term "drift" includes ground moraine, mostly unsorted stony clay and silt materials deposited under the glacier; recessional moraine, more unsorted stony clay and silt materials dumped and mounded at the snout of the glacier as it paused its retreat for periods of time; and kames, piles of water-sorted sands and gravels deposited on, within, or against glacier ice by melt-water flow; and many more drift types we won't go into here.

Delaware County is a young landscape, likely less than 15,000 years young, formed of glacial drift. Thin ground moraine covers most of the county. Ground moraines and recessional moraines are dissected by several large river systems formed during deglaciation. Geologists have mapped the glacial geology of Ohio and of Delaware County.

The Glacial Map of Ohio includes county outlines. Look for Delaware County at the center of the map colored yellowish-green (ground moraine) with dark green arcs (recessional moraines) bending southward, and a few small pink blobs (kames) in the northwestern corner of the county. Do you see the cleft in the county's central moraine? Now look for that cleft on the shaded elevation map below and you have the county located. The shaded elevation map shows the moraines as raised elevation areas. We see the river systems cutting nearly straight north-south channels through the raised recessional moraines and ground moraines alike.

The Shaded Elevation map (large file (pdf)) of Ohio helps you see drainage at large scales. Click the "+" sign in the toolbar about eight or ten times and you will zoom in on the Radnor area. Do you see the shaded arcs indicating the recessional moraines? They are dark green on the Glacial Geology map above.

Now, look at the pink blobs mapped in the NW corner of the county on the glacial map. This is the terrain pictured below.

View of glacial kame from the north approach to Radnor, Route 203.

The flat ground moraine (foreground) abruptly terminates at the base of the kame where slopes rise steeply. Coarse deposits like gravel and sand piles hold steeper slopes than fine deposits like clay and silt. A home is built on the gravelly kame. Kames are elevated, easy to excavate, and are well-drained compared to ground moraine.

Now look at it on the topographic map found at this link:

This is the map view of the kame and it is obviously narrow and long like a segment of the deposits in a stream channel. These deposits probably were laid down by water running through eroded channels on the surface of the ice sheet. When the ice melted away the supra-glacial stream deposits were piled on the ground where they remain today.

The hill in this view is a glacial kame left forested. The flatish ground moraine in foreground surrounds the kame as seen at distant left.

Cows guard access to a borrow-pit dug into the end of the linear kame. Unconsolidated sand and gravel is easily borrowed from kames and borrow-pits are common in the area.
Huge glacial erratic seen from Route 203.

Glacial drift includes erratic boulders, chunks of bedrock carried from somewhere else. This one found south of Radnor along route 203 may be the second largest in Delaware County, exceeded only by the Sunbury boulder, largest in the state (a topic for a future post). It's height exposed above ground is around ten feet. Undoubtedly, as much as half remains hidden beneath ground. This large igneous rock was carried from central Canada.

Buttermilk Hill Road, west from the record bur oak tree pictured below at the entrance to Gallant Woods Preserve, ascends a recessional moraine. Many homes are built along the crest of the hummocky moraine. The ice sheet paused for a time at this position. Glacial drift piled at the snout of the ice sheet here.
State record (second place) bur oak tree at the entrance to Gallant Woods Preserve.

Ice sheets sculpted two-thirds of the state of Ohio. It's fascinating to think of the topographic impact of these behemoths on our state and beyond. Ice sheets reduced terrain, built terrain, and altered drainage patterns over huge areas of continents. The Ohio River is a product of drainage reversal caused by ice sheets!

An immense amount of drift is carried within creeping ice sheets. Many people imagine that ice sheets operated like bulldozers surging south from points north and pushing large chunks of Canada ahead of them before quickly melting away. A venerable local county extension agent wrote a history of my home county terrain that employs this misconception; and it remains assigned reading for school children today.

I read this account as a youth and I was thrilled to adopt the misconception that our latest ice sheet, the Wisconsinan age Laurentide Ice Sheet, had bulldozed spruce trees, nearly intact, all the way from Canada to my backyard. These spruce logs were uncovered just a few miles from my home!

Of course, we know this is not what happened. These spruce trees grew nearby along the ice-front for tens of thousands of years as the ice-front dominated the south-central Ohio region for tens of thousands of years.

The dynamic ice-front moved back and forth over meters and miles during this long span of time. When the ice surged forward occasionally it bulldozed the locally grown spruce trees into jumbled piles of logs buried in glacial drift. We use radiocarbon dating to determine the age of the drift in which we find these logs! In my area they date to around 17,000 or 18,000 years ago, the time when the Laurentide Ice Sheet reached furthest south just before receding northward permanently.

An ice sheet transports drift by picking it up at its base (called entrainment) and moving it toward its margin. Drift begins its journey as part of an ice-saturated mass of bedrock blocks, boulders, gravel, sand, silt, and clay frozen to the base of the ice sheet. The mass scrapes against bedrock along the bottom of the flowing ice sheet until the mass is thrust into the basal ice layers along shear-planes and zones of deformation rising downstream from the base.

The mass is raised into the ice slowly as it is pushed from behind by the inexorable flow of ice. The resistance of the ice downstream as it is scraping along the bedrock and freezing to it in places, pushes back enough to force upstream drift masses to shear upward at low angles into the ice sheet. The drift then rides the ice south.

Often, earth scientists refer to this process as a conveyor-belt. This is helpful for visualizing the mechanism by which ice sheets convey drift from places north to places south. The giant boulder seen south of Radnor, pictured above, was conveyed to its position in Ohio from its original position somewhere in Canada by this mechanism.

Ice sheets move forward toward their margins in a fairly steady way (though punctuated by surge-pulses) pushed by accumulating volumes of ice near their centers. The ice flows away from the accumulation zone by deforming under its own weight. The accumulation zone of the eastern portion of the Laurentide Ice Sheet was at about the position of Hudson's Bay.

Far to the south, ice sheets melt back along their margins at the same time the ice is flowing forward. If they flow forward faster than they melt back, the ice-front surges ahead over virgin terrain. When the ice sheet flows forward at about the same rate the ice-front melts back, the ice-front will hold an average position for as long as this continues.

The ice sheet is not sitting still even when the ice-front is not moving forward. The ice continues to move forward all the while until the very final stages of deglaciation when large areas of ice stagnate and just melt away in position.

Generally, as the ice-front melts, the material inside the ice sheet is exposed as melt-water drips away and flows along drainage outlets as sediment-laden runoff. This runoff deposits vast outwash plains along drainage valleys like today's Scioto River Valley.

Much of the drift remains along the ice-front as broad mounds. It piles up as if it were coming off of a conveyor-belt. This is how end moraines and recessional moraines form. Their position coincides with the position of the ice-front at the time they formed. End moraines tell us how far the ice sheet flowed. Recessional moraines tell us where the ice-front paused before continuing to melt back toward its center.

When ice sheets melt back faster than they move forward, they leave behind the material frozen inside as ground moraine.

*Geologize: Applying geological principles to deduce and hypothesize geological process and history through direct observations of landscape, drainage patterns, bedrock, soil, land use, and so on.
*Kame: Steep-sided mounds or terraces of sand, gravel, and boulders. Glacial sediments laid down by water flowing on a glacier or leaving the glacier's margin, in contact with ice: Ice-contact stratified drift. Long kames are sometimes called eskers. One definition suggests that a kame ten-times as long as wide is an esker. The long narrow Radnor kames appear to have been deposited on the glacier surface as supra-glacial stream deposits, then dumped onto the ground as the ice melted away. A process definition would rank some of the Radnor kames as eskers.

Sunday, December 2, 2007

Winged things wild and free

The Ohio Bird Conservation Symposium

*Scott Weidensaul, author and bird scientist, rediscovers Wild America retracing Roger Tory Peterson's epic journey 50 years later.
*Jim McCormac, author and Ohio Ornithological Society president, shares new information in outdoor trends.
*Dr Amanda Rodewald explains the challenge of protecting the declining Cerulean Warbler.
*Paul Baicich, author and top bird conservation expert, suggests ten things YOU can do to conserve birds.
*Dr Dave Ewert shares models and visions for protecting the right habitat.
*Chris Bedel, preserve Director, introduces the amazing Edge of Appalachia.
and more. . .

Auspiciously, several flocks of migrating Sandhill Cranes flew over Deer Creek Reservoir in Pickaway County, Ohio Friday November 30 as conservation-minded birders and naturalists gathered for the Ohio Bird Conservation Symposium presented in partnership by the Ohio Ornithological Society and the Ohio Chapter of The Nature Conservancy. Great presenters and the dedicated event-planning team made this symposium a great partnership success for the OOS and TNC. See OOS President Jim McCormac's great blog (link below) for more details and pictures.

Friday evening, Jim McCormac, President of the Ohio Ornithological Society (OOS), met with generous OOS supporters and presented a new and insightful talk about trends among outdoor user-groups to illustrate the importance and the potential of bird enthusiasts pursuing their interests. Conservation dollars are scarce and habitat protection sometimes requires habitat purchase or easement--both expensive. Bird and nature enthusiasts can do much more to provide for their resource, beginning at home.

The economic impact of bird-related pursuits, from bird viewing and bird-feeding to chasing rare birds, is very much under-appreciated. We who love winged things wild and free must share the beauty, deliver the message, and participate in bird conservation, or continue to lose our resource. Ecotourism happens near home, not just in far away exotic locations. Tell the world and your local Chamber of Commerce how much we spend: It's their resource too.

Biodiversity is undervalued because we don't account for its value!

Late Friday evening (and again Saturday) a caravan of birders traveled to see the Northern Saw-whet Owl banding operation at the Earl H. Barnhart Buzzards' Roost Nature Preserve near Chillicothe, Ohio. Everyone making the trip enjoyed seeing these delightful little bundles of wonder. Some birds wake the child in us all regardless of age and bring us into touch with our sense of wonder, so often forgotten. The saw-whet is the grand champion of all avian wonder-wakers. See Jim McCormac's blog for several updates with pictures.

These OOS-partner events always draw great speakers and this one was no exception:

Saturday morning Dr Amanda Rodewald, The Ohio State University School of Environment and Natural Resources led the day with her presentation, "A Bird of Two Worlds: The Challenge of Conserving the Cerulean Warbler." The Cerulean Warbler is the OOS icon, its image the OOS logo. Dr Rodewald shared insights and research results to help fill in missing puzzle pieces for the picture of rapid Cerulean Warbler population decline. More work is needed and the OOS was pleased to present Dr Rodewald a research grant of $1500.00 to help fund continued research in both worlds, the cerulean's summertime home in Ohio and its wintertime home in South American.

Dr Dave Ewert, Director of Conservation Science for the Great Lakes Program of the Nature Conservancy presented, "Stopover Sites of Migratory Birds in the Great Lakes Region: Identification and Protection." Dr Ewert uses landscape-level modeling to identify and prioritize habitats used by migratory birds. Scarce dollars for conservation are used wisely when we use them where they make a difference. Important migration stop-over locations in the western Ohio and southern Michigan flatlands are coming into focus through the efforts of Dr Ewert and his colleagues.

Paul Baicich is a central figure in birding and bird conservation. He is author, instructor, guide, and consultant for all who love winged things wild and free. Paul's book (with J. O. Harrison, Princeton University Press), "A Guide to the Nests, Eggs, and Nestlings of North American Birds" came out in second edition in 2005. Paul presented, "The Ten Most Important Things You Can Do for Birds and Bird Conservation" beginning with the big five problems impacting bird conservation, and concluding with ten practical approaches to bird conservation beginning in your own backyard.

Making Paul's list; make your property bird-friendly (food--cover--water), drink shade-grown coffee (the real thing), buy a Migratory Waterfowl Hunting and Conservation stamp (duck stamps buy habitat), support inter-American equipment transfer (retire your old optics and nature equipment to a new life in a less developed country), support birding and nature festivals--start a family oriented local festival to help make the bird-curious bird-committed, be a friend of a local park or refuge (volunteer), take a child into the outdoors (their parents follow), count birds and make it count (CBC's, Ebird, Breeding Bird Atlas), develop a congressional relationship with a staffer (just writing your congressman isn't enough), lights-out (use efficient bulbs--only as you need them).

Bald Eagles made an appearance for lunch and were easily viewed from the lodge's Rafters Restaurant. A large raft of diving ducks bobbed in the distance too far to identify but close enough for a closer look. During the symposium participants used free time Saturday and group birding trips Sunday morning to explore for birds--no sign of the Northern Shrike that likes the location, but ducks were well represented, and Sandhill Canes trumpeted the beginning of the event.

Chris Bedel led the afternoon and kept the after-lunch crowd wide awake through a dazzling fast-paced tour of the extraordinary Edge of Appalachia Preserve system in southern Ohio, co-managed by the Ohio Chapter of The Nature Conservancy and by Chris, preserve Director with the Cincinnati Museum Center. "The Edge" is home to extraordinary diversity due to overlapping geology and biogeography. Professionals at The Edge pursue all-taxa biodiversity and share it with youth and adults.

Dinner-time is recognition time at OOS events and two powerhouse volunteers were recognized for their hard work in making OOS a success: Jen Sauter, OOS Executive Secretary and Board member, is always a big part of success and always in the background. Cheryl Harner, OOS Conservation Committee member, like Jen, works in the background to make everything happen, especially great vendors and exhibits at OOS events. Cheryl has set the bar high in conservation leadership through her work with Greater Mohican Audubon as well.

The OOS also recognized the birds by doing something for habitat: The Nature Conservancy, and all winged things wild and free, were beneficiaries of Ohio birder generosity. TNC's Pete Whan and Lucy Miller accepted a grant of $10,000 matching funds for acquisition of a great tract of neotropical migrant habitat with a globally rare white cedar plant community. This tract helps to fill an important gap in the huge and unique Edge of Appalachia Preserve system.

The evening keynote address presented by author and bird scientist Scott Weidensaul took us on a breathtaking tour of North America's wild places retracing the steps (30,000 miles) of famed ornithologists and authors Roger Tory Peterson and James Fisher in 1953 detailed in their book, Wild America (1955). Weidensaul's descriptive words and shared insights, more than his stunning images, carried his audience breathless through a fifty-year comparison of wild places tracked by Peterson and Fisher, then by Weidensaul. At the end of the journey we found a new beginning. There was no pot'o gold at the end of the rainbow; in its place we found a hope chest of mixed memories, on balance good memories, and reasons to be optimistic for conservation successes in the future. I bought Scott's book, "Return to Wild America: A Yearlong Search for the Continent's Natural Soul (Long Point Press, 2005).

Sunday morning breakout sessions offered something for everyone. Jim McCormac presented, Wonderful Waterfowl. Aarone Boone, Ohio Breeding Bird Atlas Coordinator, presented, "Sparrows 101". Paul Bacich presented, "The Five Best and Worst Things About the Duck Stamp."

Field trips Sunday mid-day canvased the Deer Creek area for birds. Look for reports on the Ohio Birds Listserve.

Wednesday, November 28, 2007

dkh, Big trees and young children

Professional foresters measure tree diameter using a standard timber cruising measure known as "dbh" (diameter breast height). It's a great way to help youth learn to use measurement in the 'real world'.

A different approach will get better results when young children do the measuring. We suggest using the "dkh" (diameter kid height) method shown here.

Young tree-huggers practice the dkh method of tree measurement.
This is a three-kid white oak, a real nice tree!

Urban Metro Parks and County Preserve systems offer great nearby locations for youth to experience Ohio's woods and fields--most children today do not have access to a family farm and state parks are usually not in the local community.

The really great local preserve systems provide ample opportunities for youth to escape the beaten path, to tromp on fallen leaves and to get their hands on nature.

Let's face it; walking a manicured trail is more nature viewing than nature learning. Television nature programs would quickly lose their young audience if they didn't bring their viewers up close and personal using extraordinary close-up photography of nature. It's the same in local parks: The view from the trail is scenery. Off the trail opportunities are close-ups with benefits. Hands-on learning is an experience, not a program.

I volunteered to help offer some local youth a few close-up nature opportunities last Friday at Gallant Woods Nature Preserve in Delaware County's Preservation Parks. My thanks to Preservation Parks for the opportunity to volunteer. Professional Naturalist and Education Coordinator, Jackie Brown (behind the camera), creates hands-on nature learning for youth throughout the properties in the Preservation Parks system and in many community schools.

Your support is important to your local parks, wherever you are.

Tuesday, November 27, 2007

Mollusc madness

A story of fresh water mussels: Will we lose the "snot-line fishing mussel"?

Ohio's diverse native fresh water mussel fauna has suffered extinctions, extirpations, and severe population declines while introduced species like Asian clams and zebra mussels have enjoyed population explosions in rapidly expanding ranges. And; more invasive species wait in the wings ready to invade. It's only a matter of time.

This sad story is not unique to Ohio. From Ohio's purple cat's paw mussel to Alabama's "snot-line fishing mussel", most species are in decline and many have already been lost in time like the fleeting brilliant glimmer of a raindrop splashing stream water above a sandbar mussel bed.

It's a mess!

Dr. Tom Watters, mollusc expert with The Ohio State University (GO BUCKS) brought his talk, "Freshwater Mussels: From Living Rocks to Mean Mothers" to Hopewell National Historical Park near Chillicothe, Ohio for presentation to the Scioto Valley Bird and Nature Club Monday night November 26.

G. Thomas Watters, PhD
Curator of Molluscs
Department of Evolution, Ecology, and Organismal Biology
The Ohio State University

It's a story of silent disappearance:

Freshwater mussels originated in North America long long ago in a place not very far away (right here in the Mississippi watershed) sometime during the Triassic Period when the biggest things disturbing them were dinosaurs. These dinosaurs were far less effective mussel killers than today's human poachers collecting for the cultured pearl trade--a continuing modern threat to rare mussels.

The Mississippi watershed is ancient, and throughout the undisturbed native river system there were riffles, rapids, sandbars, emergent vegetation like water willow, snags and sawyers, stream side shade trees, low silt loads, no industrial chemical pollution, and most importantly, seasonal rise and fall in river system water levels; the slow heart-beat of the continent.

The undisturbed heart-land offered habitat heterogeneity throughout ancient natural continental arteries, the streams and rivers of unspoiled North America. The Mississippi watershed supported the diversification of our mussels in diverse streams and rivers rising in diverse geology and physiography. North America once supported more than 300 species. The vast Mississippi river system, heart of our continent, supported great fish diversity too, and mussels rely on fish to complete their life cycle, and they rely on fish migration to disperse them.

North America is the center of diversity holding most of the world's species. The Mississippi River watershed is the heart of this diversity.

The life cycle of mussels may span decades yet aged individuals may never leave a particular sandbar. They are ingenious creatures--well, they have evolved ingenious reproductive strategies to ensure their propagation and dispersal--under natural conditions.

Pictured above is a fish mimic structure used by the mussel to bring host fish close enough to inhale larvae (original presentation photo by G. Thomas Watters, PhD)

My favorite species, introduced to me through video by Dr. Watters at our meeting, has an impossible Latin name so I'll toy with Dr. Watters' description and call it the "snot-line fishing mussel". It occurs only in Alabama, but we won't hold that against the creature.

Picture this:

The female snot-line fishing mussel, a fist-size denizen of river sand, spends most of her life softly filtering stream water for nutrients--just about anything biological that she can filter. At maturity, she is compelled to reproduce. When she has received semen, randomly released into the water by her local male mussel, she is soon ready to go fishing for her host, the Suwanee bass. She is particular about her host selection and no other fish species will do!

She grows a zillion little fertilized larvae called glochidia. She is expert at the small egg gambit wherein she plays the nickel slots rather than high stakes poker! She does this by making a zillion tiny glochidia for release--a zillion nickel bets. The slots need pay only once. Any given individual has a very very low chance of survival but by releasing so many she hedges; success through overwhelming numbers--small inexpensive (energy-wise) larvae.

She packs these zillion glochidia into a fish lure, that's right, a small fish-looking glochidia container, another hedge. Now she produces a long thin strand of mucus (snot-like) fishing line that is nearly invisible in the water and a good 18 feet long! Guess what's at the end of the line? Yeah, the fishing lure. It even wiggles in the current!

Well, the unwitting Suwanee bass can't resist the lure and when it bites into it the lure explodes in its mouth releasing the zillion glochidia. Some of these land among the gills where they clamp on like tiny bear traps and hitch a ride with the bass while they develop into small adult mussels. Eventually they will drop off and make a home in the sand for the next few decades, softly filtering stream water--and playing the nickel slots.

The story of loss of freshwater mussel species is dismal. Surely, we would have acted sooner and more effectively if these creatures were showy flights of fancy like many of our birds, for example (though we have lost wonderful birds like the Passenger Pigeon and the Carolina Parakeet).

The numbers tell the dismal story:

Of the nearly 300 North American species about two dozen are already extinct and about 20% of remaining species are federally endangered. Fresh water mussels are the most imperiled animals in North America by percentage. Only about one-third of North American species have stable populations.

Ohio has a large share of mussel diversity but of our 80+ native species we've already lost six species to extinction and several others are in precipitous decline. Another 13 species have been extirpated from our state.

Mussels suffer numerous threats. Among these the most profound has been the damming of rivers and streams into series of lakes that drown habitat heterogeneity. These dams are like clots in the heartland's arteries. They are good for boats and commerce but they attack the heart of our natural waterway system. Further, siltation of streams weakens and suffocates many species. Industrial and agricultural pollutions take their tolls, too. And, urbanization channelizes and homogenizes our once diverse headland streams.

Perhaps the most disturbing and surprising loses are due to commercial mussel harvest still legal in several southern states. Even more surprising is the commercial mussel poaching in Ohio and other states responding to the need to protect fresh water mussels. Teams of night-operators illegally collect tons of mussels to sell in the cultured pearl manufacturing trade--most of which go overseas. Our freshwater mussels are the magic secret to success of cultured pearl manufacture. Our mussels are collected for the fleshy lining of their shells that seeds the oysters making the pearls.

The harvest of native mussels should have ceased when the invention of plastic buttons replaced mussel shell buttons at the turn of the last century but vanity rules worldwide demand for pearls today just as vanity ruled the hat-making trade in days gone by when fancy-plumed hats were in such demand that plume hunters nearly wiped out showy bird species. Late in the Nineteenth Century the worldwide market for plumes lured commercial punt-gun and net hunters into all corners of the globe--but mostly in our United States. The trade stopped only after loud protest and a shift in ladies' fashions.

Unfortunately for our native mussels they are not showy charismatic creatures like North America's Snowy Egret or Indonesia's Birds of Paradise. Mussels don't demand our attention (until you see Dr. Watters' videos of mussel fish lures).

Who protests for fresh water mussels? How many women examine the origin of their cultured pearls?

Native mussels continue their silent decline. We may lose the rare snot-line fishing mussel unless we protect and restore the ancient rhythm, the rise and fall of continental waters, the natural heart-beat of North America. And, we may never restore the rare mussels until we reevaluate our fascination with cultured pearls.

The content above is based on my memory of Dr. Watters' presentation so if there are errors they are mine. Use these websites for additional authoritative information:

Visit the OSU Division of Molluscs at:

Join the Freshwater Mollusk Conservation Society at:

Educators, this pdf is the place to start:

Additional agency resources:

Monday, November 26, 2007

Maple leaves: beauty in function

Seasons come and go and with them the ebb and flow of warmth and waters in Ohio. Our Autumn colors signal the time for the rains and rising waters of winter.

October maples ablaze in southern Ohio

The beautiful reds and yellows of maple tree leaves demand our attention every Autumn and paint glossy calendar and magazine pages year-round. These are brilliant colors for sure, but do we overlook the beauty of function in their exquisite leaf-shapes? When leaves are down and brown and gray trees pierce the cold blue sky of winter, do the leaves serve the resting trees?

Look at one great example, the silver maple (Acer saccharinum). This maple species is adapted to unconsolidated Recent alluvium (fancy geo-lingo for rocky-sandy-muddy stream deposits of Recent Era vintage) where its sprawling muscular roots reach shallow groundwater while grasping great globs of stream side silt to secure its foundation against flood. It grows fast and branchy along moist bottoms of our meandering stream ways. Its fast growth and broad shadow entices developers selling cheap landscaping for new homes, but plagues future homeowners with shed branches and massive leaf-falls.

It's the massive leaf-falls that suggest function in the shape of silver maple leaves; a function unrelated to photosynthesis. Look closely: The deep sinuses between leaf-lobes and coarse teeth identify the leaf as silver maple and suggest an adaptive function when you see them laying piled on the ground. The toothy sinuses interlock with each other forming a thick layer of slowly decaying leaves that resist wind and water.

The silver maple dominates vast stretches of Midwestern streams and I'm sure this results from the beautiful function of interlocking leaves blanketing silty stream banks and smothering seedlings of competing tree species. Frequently shed branches pile up under silver maples and slow flood waters assisting silty deposition while less adapted tree species are undermined by erosion.

Beauty is often beyond the eye of the beholder.