Karl Overman: Birds and more

 
 


For much of the Twentieth Century, southern Michigan was the southeast extremity of the breeding population of the Greater Sandhill Crane (Grus canadensis tabida) so it has always been a favorite of Michigan birders and ornithologists.  The man who wrote the book on cranes, literally,  Lawrence Walkinshaw, lived in Michigan.  During the years 1931 through 1946, he determined that the number of nesting pairs of Sandhill Cranes breeding in southern Michigan ranged from 15 to 27.  L.Walkinshaw, The Sandhill Cranes 134 (1949). During that 15 year span, the number of nesting Sandhill Cranes in Washtenaw County was constant--one!  The exclamation mark is warranted because today in much of Washtenaw County, despite a huge human  population increase since the 1940s, Sandhill Crane is a common bird.   This is a bird once considered a symbol of the wilderness and doomed to disappear as the wilderness disappeared:


The advances of civilization, the drainage of swamps and the cultivation of prairies have doubtless driven this wary, old prairie scout away from all the central portions of the United States; and they are still driving it further west and north into the unsettled wilderness; the wilderness is fast disappearing and with it will go the cranes and many other interesting forms of wildlife.


Arthur Bent, Life Histories of North American Marsh Birds  241 (1926).


That dire prognostication has proven over time to be dead wrong. The number of breeding Sandhill Cranes in Michigan has vastly increased in recent decades and it has resumed breeding in states such as Illinois, Indiana and Ohio where it had been extirpated as a breeding bird.  Instead of being confined to wilderness settings, Sandhill Cranes are now a creature of suburbia, well at least exurbia. This increase was well underway in the 1970s and 1980s and continues to the present.  For example in a study area in Waterloo twp., Jackson County, the number of Sandhill Cranes went from 58 to 98 between 1970 and 1982.  Ronald H. Hoffman, Changes in the Wetlands Selected by an Increasing Sandhill Crane Population Jack Pine Warbler 61  2  p51 1983.  At the same time the average size of wetlands used by cranes declined 34% from 58 ha in 1978 to 38 ha in 1982 Id. at 54.


The status of Sandhill Crane in the Great Lakes area has changed in more ways than in its breeding range and abundance as a breeding bird. In spring, Sandhill have moved up their arrival dates for southern Michigan.  In Walkinshaw’s book on Sandhill Cranes  (Id. p135), he breaks down the number of cranes seen each month in southern Michigan.  During the course of field work spread over seven years in the 1930s and 1940s,  there were no February sightings of  Sandhill Cranes in southern Michigan. In contrast, under current conditions, if you are doing a February Big Day in Michigan, Sandhill Crane is a bird you count on getting--at night preferably.  February arrivals in Michigan are not something that has suddenly started happening however.  See, e.g., “several pairs, Waterloo twp., Jackson Co., February 26, 1977 Ronald Hoffman, Jack Pine Warbler  55  2 p. 81 (1977).  However the expectation of arrivals in February instead of March is relatively new.


As for fall,  again reviewing Walkinshaw’s table on monthly sightings in southern Michigan in the 1930s & 40s, it is apparent that peak fall numbers were in October with only a few or no cranes being seen in November. And forget about December records.  Peak numbers in southern Michigan still are often in late October but impressive numbers can be seen into November during the past decade, e.g., 4019 on November 19, 2001 at the Haehnle Sanctuary in Jackson County.


Historically Sandhill Cranes did not winter in Michigan.  In fact in Walkinshaw’s book on Sandhill Cranes  (Id. p135), when he breaks down the number of cranes seen each month in southern Michigan, there are not even cells for December and January. In the late 1990s there was a series of winters distinctly milder that was the norm in Michigan and it was striking how Sandhill Cranes quickly altered their behavior to make use of the warmer winter conditions.   Consider Christmas Count records for southeast Michigan, normally a good indication of species status in early winter. In the 1970s there were a few Christmas Count records from the Waterloo area of Jackson County:


1 (species highlighted) January 2, 1971 Waterloo CBC (believed to be an injured bird) American Birds 26  2 p 362 (1972)

2 December 29, 1973 Waterloo CBC American Birds 28  2 p370  (1974)

1 December 28, 1974 Waterloo CBC American Birds 29  2 p399 (1975)


In the 1980s it was still highly unusual to find Sandhill Cranes on Christmas Counts:


10 December 19, 1987 Waterloo CBC American Birds 42  4 p867 (1988)


Then in the 1990s, the numbers of cranes on Christmas Counts took off:


86 (number highlighted) December 15, 1990 Waterloo CBC American Birds 45 4 p.793 (1991)


1 December 20, 1992 Monroe CBC American Birds 47  4 p752 (1993)

53 December 19, 1992 Waterloo CBC American Birds 47  4 p755 (1993)


1 December 16, 1995 Monroe CBC  CBC Field Notes, 50  4 p630 (1996)

8 December 16, 1995 Waterloo CBC CBC Field Notes, 50  4 p633 (1996)

98 December 21, 1996 Waterloo CBC  Field Notes, 51  2 p416 (1997)

46 December 20, 1997 Waterloo CBC American Birds p. 302 (1998)


2 (species highlighted) December 19, 1998 Ann Arbor CBC American Birds p. 294 (1999)

131 December 27, 1998 Flint CBC (birds all in Livingston Co.--photo below) AB p. 298 (1999)

21 December  18, 1998 Hartland CBC [Livingston Co.]

1107 December 19, 1998 Waterloo CBC AB p306 (1999)


2 December 19, 1999 Detroit CBC [Oakland Co.]

308 December 18, 1999 Flint CBC [Livingston & Genesee Cos.]

20 December 18, 1999 Hartland CBC [Livingston Co.]

1 December 18, 1999 Pontiac CBC

903 December 18, 1999 Waterloo CBC  AB p 319 (2000)


On occasion, even large flocks have been found well into January in Jackson County, e.g., 521 January 26, 2007 Lathe Claflin, Don & Robin Henise. 


That does not mean then when harsh winters return, as they have a number of times since the 1990s, that the cranes are somehow trapped into a new life pattern that prevents them from migrating--they still move out when conditions get too wintry.  Nonetheless the Sandhill Crane is an interesting case study in how apparently climate change, be it short term or long term, can quickly lead to adaptation by a species.

Sandhill Crane  (Antigone canadensis)

Modified August 12, 2016