Tuesday, January 29, 2019

GBH's: Phantoms of the Marsh

Apparently these eight ghostly images, taken huddled amidst yesterday's dormant cattails and snow and part of
a much larger group, haven't read the literature that they really aren't supposed to winter in Ohio

For decades now, Great Blue Herons have congregated in springtime on my family's farm just south of Toledo, setting up shop by the dozens. They first established their rookery (breeding colony of "rooks," typically seen as a collection of nests high in a cluster of trees) in the tallest ashes and cottonwoods, and since those early years (despite downed trees from high winds and a little green beetle from a far away land) the number of nests have only multiplied.

At any given time, typically from mid-March through at least August, we can see up to a hundred of these prehistoric-looking "waders" on the wing. Just last summer, my uncle witnessed 50+ of the clumsy, newest recruits on his dock, having just fledged and looking for an easy meal. My childhood home wasn't just an oasis for me; the 10+ acres of pond (or "lake," as we proudly call it) is surrounded by two distinct tributaries of the Maumee River that meet in the northeast corner of the land, just north of the established rookery. Fish abound. And as such, so do herons.

Wish we could claim this magnificent image as our own; it's borrowed for a few reasons: (1) the mid-strike pose is
just plain iconic; (2) its prey (a juvenile Pumkinseed) is currently a dominant species in the marsh (click to see detail)
-- and one of my favorites; and, (3) when we think of GBH's, most think of vibrant colors and warm summer days

The marsh is really no different. Food is plentiful -- not just in the form of a broad diversity of fish, but also in crayfish, frogs, snakes, and really anything else a Great Blue can spear (which is pretty much everything). Shallow water and plenty of cover make for perfect hunting. As a result, we are graced by lots of "feathered pterodactyls," as one of my brothers likes to call them. Their silence-shattering screech is a nightly ritual on the marsh . . . as well as a childhood memory on the creek bank -- where many an unsuspecting heron forced the hair on the back of my neck to stand on end!

These birds are known for being able to go "motionless,"
and this handful did not budge while Roy fired away
multiple images from hundreds of feet away
But what we've found to be unique at Standing Rush is (1) these somewhat common birds are extremely camera shy, and (2) they haven't read their own bios on the Ohio Division of Wildlife's website: The herons will migrate to warmer areas with unfrozen waters in the winter; rarely does a great blue heron remain in the state at this time of year.

It is not unusual for us to see 40-50 GBHs standing together on an ice covered marsh. I'm convinced they are drawn to us not only because there is enough open water (or ice) that they can collectively keep eyes pealed for danger, but they also seem to like what ends up frozen in the top few inches of our ice each winter -- thousands (maybe tens of thousands) of 2-4" Gizzard Shad that enter the marsh tipped by subtle temperature cues, only to succumb to a rapid rise or fall in temperature (and therefore, available oxygen).

At first glance, these loitering rafts of herons don't seem to move a muscle. Even stiff north winds barely seem to unsettle their elegant feathers. But if you give yourself the opportunity to watch them in the cold, they still exhibit their telltale habit of careful inspection and laser precision. Lucky for them, frozen Gizzard Shad are a little easier to capture than a spunky, summer Pumpkinseed.