(This column was first published in the June 21, 1999 Buffalo News.)
Jared Potter Kirtland was an 18th century Ohio physician whose biological avocations earned him several natural history honors. Kirtlandia, the journal of the Cleveland Museum of Natural History is named for him as are two species, Kirtland's water snake and Kirtland's warbler.
Spencer Baird of the Smithsonian Institution named the warbler based on specimens collected by Dr. Kirtland near his Ohio home. Sadly it is long gone from that area and it became one of our most endangered birds, its breeding range restricted to a few square miles.
In mid-June Mike Hamilton and I drove to Grayling, Michigan to see this rare bird. There we joined a tour of the jack pine plantations that are carefully managed to support this warbler as part of a program sponsored by the U. S. Fish and Wildlife Service, the U. S. Forest Service, the Michigan Department of Natural Resources and the Michigan Audubon Society. Our excellent guide was F&WS officer Tammy Giroux.
There were about twenty birders in our group. Much to our surprise, seven of them turned out to be members of Rainbow Country Birders of Niagara County.
Before we ventured out into the plantations, we were provided some background. We learned that the number of Kirtland's warbler pairs dropped from almost 600 in 1961 to 201 in 1971, biologists identifying two causes for this precipitous decline. The first, cowbirds laying their eggs in warbler nests and crowding out the warbler chicks; the second, loss of habitat. These warblers require very specific breeding grounds and the pines here were growing too tall.
The first problem has been solved by trapping and removing thousands of cowbirds over the years. The second, more difficult problem, has required a carefully managed tree harvesting cycle.
Nature originally managed these trees through lightning-ignited fires that destroyed trees when they grew too tall and at the same time burst their tightly sealed cones to provide new seedlings. Now, with fires strictly controlled, the 210 square miles of plantations go through a three stage management cycle, each year only one-third providing the required habitat for the warbler.
Our caravan now proceeded out into a beautiful day, clear blue skies over the rich green of the pines. No sooner had we parked and started down a trail into a plantation than we heard the loud song of our target bird. Within minutes we had binoculars and telescopes focussed on the handsome gray and yellow songster and we could watch him proudly proclaiming his home territory.
There was other wildlife as well. A hermit thrush provided an organ background to the warbler's refrain and a thirteen-lined ground squirrel -- a chipmunk look-alike -- bustled about in the thick undergrowth. I knew this little rodent from summers at Notre Dame in Indiana and whistled it in close for others to see.
Ms. Giroux showed us one of the cowbird traps. In it several well-fed birds play the role of Judas goats. Attracted by them, other cowbirds fly in through holes in the trap roof and are unable to fly out. Each day several are removed.
Management has been successful. Today there are about 800 pairs of Kirtland's Warblers and the birds have even established a new breeding area on Michigan's Upper Peninsula. When they reach 1000 pairs biologists plan to remove them from the endangered species list.
To some this may seem like a large investment to protect one little warbler. Don't tell that to local residents whose economy benefits from the many tourism dollars spent by those who come to see this rare bird. And all of us should support this program for its ecological, historical, educational and esthetic values. -- Gerry Rising
Note: There are many informative web resources devoted to the Kirtland's Warbler. A useful start in investigating them would be at Owashtanong Islands Audubon Society's Kirtland's Warbler page or the F&WS page devoted to this bird.