“…a pandemonium of trumpets, rattles, croaks, and cries that almost shakes the bog with its nearness, but without yet disclosing whence it comes. At last a glint of sun reveals the approach of a great echelon of birds. On motionless wing they emerge from the lifting mists, sweep a final arc of sky, and settle in clangorous descending spirals to their feeding grounds. A new day has begun on the crane marsh.”
—excerpt of Aldo Leopold’s essay “Marshland Elegy” from A Sand County Almanac
On the wing from Florida, sandhill cranes arrived in Wisconsin over the past few days. A mini celebration ensues upon the arrival of these cranes. I’ve received texts, calls, and read reports online. What joy these birds can bring as the snowpack stalls and becomes stale; the routine of winter becoming so entrenched that these birds flying north bring assurance that the comfortable rhythms of winter are soon to be succeeded by awakening wildlife, birds, plants, and sunlight.
On Sunday I saw my first sandhill crane of the year, flying determinedly into a strong west wind gusting over 30 miles per hour. There was no pandemonium of trumpets; the bird flew silently into the wind.
The determination of these early arriving cranes is admirable. Not only is the snow deep and the wetlands frozen, but this early arriving crane flew headlong into eye-stinging winds.
At the time of Leopold’s writing of Sand County Almanac, there were about 30 pairs of sandhill cranes in the entire state of Wisconsin. Today, multitudes of sandhill cranes migrate, sometimes in huge flocks of thousands of birds. At 20,000 birds, the population in Wisconsin is stable, and reveals an incredible success story for conservation.
Genetic research has shown that while these birds have increased genetic diversity and mixing since a bottleneck in the 1930’s, there are a number of unique sub-populations of cranes. These sub-populations could provide the key genetic material for unforeseen pathogens or diseases in the future, and illustrate why protection remains important.
Most of our Wisconsin birds come from the southeast, mainly Florida, and they are arriving right on schedule. Last year I saw my first pair of cranes flying north over the Kettle Pond on February 20th.
During migration, sandhill cranes will “stage” and group together in communal roosts in areas with good habitat and food availability. Key staging areas include the Platte River in Nebraska in spring for the western population and Crex Meadows State Wildlife Area and the Aldo Leopold Foundation on the Wisconsin River in the fall for the eastern population moving through Wisconsin. Research has shown that sandhill cranes prefer to roost on wide rivers with relatively short vegetation on the banks. Thus, rivers on an open prairie landscape like Nebraska are perfect for migrating cranes. These iconic rivers can protect the cranes from predators, as their sightlines are increased and sandbar islands provide another barrier to potential predators.
Upon landing in Wisconsin, cranes will stake out a nesting site in a wetland area. A study in southeastern Wisconsin found the highest density of crane nests on floating bog mats, where water prevents encroachment from predators. Floating bog and sedge mats are excellent spots to observe (from afar) sandhill crane nests at Faville Grove Sanctuary. As winter thaws and wetlands become accessible again to cranes, we’ll start seeing greater numbers migrating through. For now, the few intrepid cranes heading north are delightful in their own right.
Written by Drew Harry, Faville Grove Sanctuary land steward