Sandhill Cranes are links to nature’s survival schemes
By GARRY BRANDENBURG
SANDHILL CRANES ( Grus canadensis) are large, vocal and spectacular. They are long-lived and have a very slow recruitment rate. Their young, just one or two per pair per year means that in any given larger population, only 10 to 15 percent of the birds are juveniles. Young must make it through years one and then at least two more years, so that at age three, four or five will advance into adulthood and become breeding birds.
Biologists and taxonomists who study cranes know that there are six populations (subspecies) for consideration for management purposes. They are known as the Pacific Coast, Central Valley, Lower Colorado River Valley, Eastern, Rocky Mountain and Mid-Continent subspecies. They all look identical. However, deep down in their ancient natural history are subtle differences.
The Sandhill Cranes featured in today’s photograph are from the Eastern subspecies population. They winter in Florida and migrate each spring to portions of Illinois, Iowa, Wisconsin, northern Indiana and Ohio, Michigan, eastern Minnesota and southern portions of Ontario and Quebec, Canada. The huge masses of Sandhills going through Nebraska winter in Texas, New Mexico and Mexico. Once they leave wintering areas, their travel route squeezes them like a funnel into the Platte River of Nebraska where they rest, feed and gain energy for continued flight into northern Canada, Yukon, Alaska and Siberia.
As depicted in the photograph, Sandhills during their bonding and breeding phase each spring will “dance” with each other. It seems to be a spontaneous and infectious nuptial behavior whereby one bird will jump high with outstretched flapping wings and the other will respond in a similar fashion. All this jumping is accompanied by a raspy twittering call. Then just as quickly they go back to casual feeding as they hunt for insects, worms or other aquatic morsels. Keep watching diligently because at any moment the “dance” may resume. It is fun to see and fun to be able to capture this behavior with a camera.
As previously noted, the Sandhill’s ancient lineage dates back at least 2.5 million years. Throughout these long ago geologic time frames, Sandhills had to adapt to changing environments that you and I would call extreme. On the one hand are warm interglacial periods, like we are living in now, to the flip side of extended 100,000 year, or more, long embedded North American lock downs under glacial ice. Iowa’s geologic history notes that during the last 2.1 million years, at least eight huge glacial episodes impacted all the USA’s northern states and all of Canada and Alaska. In fact the entire northern hemisphere of Europe and Asia experienced similar icy lockdowns.
But glacial ice melts, and reforms due to natural forces acting upon earth such as the Sun’s output of energy, earth’s orbital variation, axial tilt variations and wobble of its axis over time. The combination of these galactic huge forces are the majority of the reasons glacial systems come and go and are repeated over and over during geologic time. It is interesting to note that through all of these climatic changes, Sandhill Cranes witnessed the entire spectrum, adapted and remain survivors we are fortunate to witness today.
Observing Sandhill Cranes locally is a hit and miss proposition. Lucky you if you see them and have the correct visual aides of binoculars and spotting scopes. Otter Creek Marsh in Tama County have several pairs of Sandhills nesting near this 3,000 plus acre Iowa Department of Natural Resource wetland complex. The birds featured in todays photo live on private lands between Marshalltown and Albion. If their movements happen to put them closer to Highway 330 near Albion, enjoy the opportunity to see Sandhills for yourself.
WARMER WEATHER is right around the corner. So are spring rains. And so are morel mushrooms. It will take into next month at this time to be fully into morel mushroom hunting mode. Many folks look forward to finding these fungi parcels under emerging forest floor plant growth. Morel mushrooms are a delicacy for ones taste buds, a spring right-of-passage if you want to call it that and a great excuse to go outside for fresh air and exercise.
FISHING LICENSES and daily fish possession limits, are NOT rescinded as some rumor mill posts may indicate. The current preoccupation with COVID-19 health issues is to be taken seriously. However, not everything is closed, canceled or suspended. Life must go on and to the best degree we can, we to have to adapt, improvise and overcome and comply with professional health care provider recommendations. Time spent fishing is not counted against ones lifespan. So to live longer, go fishing often.
HUNTER SAFETY CLASSES through the end of April are cancelled so that large groups of people will not have close contact with each other. For Marshall County, the first of the year hunter education class will be in May. Time will tell if the COVID-19 episode will have subsided sufficiently by then. For now, the May 21 and May 23 dates are open for registration. Registration must be accomplished online at the DNR website www.iowadnr.gov/Huntered.
IOWA TAXIDERMISTS ASSOCIATION was to have met at the Meskwaki Casino this weekend. The facility is not available at this time. So officials with the Iowa Taxidermists Association called their members to tell them to stay home. A new date has been set for July 18. This annual gathering is a showcase and educational opportunity for members and visiting public to learn more about the art of taxidermy. Stay tuned for a reminder later this summer as the date gets closer.
Garry Brandenburg is a graduate of Iowa State University with BS degree in Fish & Wildlife Biology. He is the retired director of the Marshall County Conservation Board. Contact him at PO Box 96,
Albion, IA 50005.