On May 13th 1851, on a farm near Cleveland Ohio a gunshot shattered the silence and a small bird tumbled lifelessly to the ground. Upon approaching his quarry Dr. Jared P. Kirtland, a physician/naturalist, realized he had something very special. The specimen was prepared and sent off to the Smithsonian Institution in Washington where it was identified as a previously undiscovered species. Eventually this new bird would come to be named after Dr. Kirtland. 28 years later it was discovered that kirtland’s warbler spent the winter in the Bahamas but surprisingly the first nest, just north in Oscoda County Michigan, was not discovered until 1903.
The story of the kirtland’s warbler is rife with drama. It is probable that the population of this diminutive little song bird was never very large due to its very specialized habitat requirements. Kirtland’s warblers will only nest in young jack pine forests preferably 80 or more acres in size. They nest on the ground under the lower limbs of 5 year old jack pine trees. As the trees age the lower limbs begin to die and by about 15-20 years of age the jack pines are no longer suitable for nesting use. On average a nesting pair needs about six acres of such forest to raise their young.
Logging in the late 1800′s and early 1900′s left behind a plethora of young jack pine stands and thus the warbler population boomed, peaking in 1885. Yet one century after the bird’s discovery, the population was perilously low. A 1951 singing male survey revealed just 432 males. Why? Before European settlement naturally occurring wildfires maintained the balance of young jack pine stands and mature forest. When the logging ceased the forests matured. That, coupled with modern fire suppression practices, meant no younger forest was being produced. In 1957 the U.S. Forest Service and Michigan Department of Natural Resources began to manage areas specifically for kirtland’s warblers. The 1970′s saw 134,000 acres set aside to be managed for kirtland’s warblers. Yet by 1973 there were only 216 singing males and 53% of that population resided on these managed lands. Clearly this puzzle was missing a large piece. The long term population trend showed a decline in numbers! Land managers now found themselves in a position where the survival of a species depended on them and there best efforts were not enough. The balance of nature was gone, it was now up to us to make certain this special creature would survive. But how?
Unbeknownst to them, early settlers were creating a precarious situation for another of our native birds that, over a century later, would manifest itself in the near loss of kirtland’s warbler. Historically brown-headed cowbirds followed buffalo, feeding on insects stirred up by the massive herds. The problem with this nomadic lifestyle, however, was that it made it impossible for cowbirds to settle down and raise young. The solution? Simple. Lay your eggs in another bird’s nest and let them raise the young while you follow the herds. The opening of forested lands in the 19th and 20th centuries along with the loss of buffalo and the introduction of cattle gave the cowbirds little choice but to move east and adapt or be lost to the winds of extinction. So move east they did and upon arriving in Michigan they found the perfect nest host. Having not evolved with cowbirds around kirtland’s warbler knew nothing of how to defend it’s nest against such intruders. Cowbirds layed there eggs in the warbler nests and the warblers spent all there energy feeding the larger more aggressive young to the peril of there own young. Subsequently the warblers lost over half of their young every year. Even with the forest service now managing the cowbird population, by 1987 there were just 167 singing males. The 1980′s, it seemed would be the decade we said a mournful goodbye to the kirtland’s warbler.
In 1980 a controlled burn by the U.S. Forest Service turned into tragedy when unexpected winds spread the fire, burning 25,000 acres and claiming the life of a forest service firefighter. This unexpected mistake although a harsh reminder of nature’s power did have a positive side. By 1987, the year the warbler population was wavering on the brink of extinction, this 25,000 acre area was of age to support breeding pairs of kirtland’s warblers. Through continued management of forest areas and cowbirds and through a tragically lucky accident we didn’t loose the kirtlands warbler. In fact as of the 2008 survey, there were 1808 singing males.
I was blessed enough to spend a few days in the area of the Mack Lake Burn (where the 25,000 acre wildfire occurred). The warblers were already on there way to the Bahamas by the time I arrived. Being in that place and not seeing them or hearing them… Thinking about how close we came to that being a forever reality was emotional. Chances are kirtland’s warblers will always need assistance from us because we have so radically changed the face of the landscape that they call home. Isn’t it ironic that, after all the good work we did to try and save them mother nature stepped in as if to say, “I’ve been doing this for millions of years,let me show you how its done”, thus saving the kirtland’s warbler from extinction.