OWC had some out-of-town visitors this weekend. In the small wetland ponds just outside our Woodstock, Illinois “green” campus, a pair of sandhill cranes were spotted.
“Great,” you might say, “but what’s so newsworthy about that?”
Well, throughout most of the 20th century, seeing a sandhill crane in this area was a fairly rare occurrence. The pair visiting were most likely the Greater Sandhill (Grus canadensis tabida) variety. Due to habitat change and hunting practices, by 1940 these cranes had been reduced to under 1,000 individuals. They have since recovered; according to the US Forestry Service, the current population is estimated to be between 65,000 and 75,000. Combined with the other migratory subspecies of sandhill cranes (the Lesser and the Canadian), with whom interbreeding often takes place, there are over 500,000 sandhill cranes, making them the most plentiful crane alive today.
Unfortunately, their non-migratory cousins to the south – the Cuban, Florida and Mississippi varieties, aren’t so lucky. Of those three, the Florida sandhills are the most populous with between 4,000 and 6,000 individuals. Cuban sandhills only have 300 left. However, the populations are fairly stable, with new populations of Cuban sandhills recently identified. The Mississippi sandhills, however, are in the most trouble – with a wild population of about 120 birds, any increases in population have come from “assistance” from conservationists; reproduction in the wild is well below “replacement” level.
While hunting played a part in reducing these populations, it’s mostly been loss of habitat that’s most affected the sandhill crane population. Sandhill cranes primarily live in open freshwater wetlands, shallow marshes, wet meadows, and adjacent open grasslands, stubble fields, and savannahs. As more and more of these areas are drained and/or “reclaimed,” the available roosting and/or migration staging areas are greatly reduced.
That’s probably part of the reason for our visitors last week – our LEED Platinum Certified building is surrounded by wetlands conservation areas – just perfect for a brief stopover from some sandhill cranes.