The Kirtland’s Warbler is a relatively large warbler with a booming voice and a boisterous personality. If you visit their prime breeding territory in late June, you will readily find the males singing their lungs out from the tops of the ten-foot Jack Pines that they call home.

Unfortunately, the Kirtland’s Warbler’s breeding territory is not as expansive as its personality. They are almost completely dependent on Jack Pine scrubland habitat in the north-central area of Michigan’s lower peninsula. More specifically, they need young Jack Pines between five and ten years old, whose dense lower branches provide perfect hiding places for their nests. Once the pines are over fifteen years old, the bottom branches thin out, and they no longer provide good cover for the Kirtland’s Warbler to nest.

Until the 1800s, periodic natural fires would clear out large tracts of mature Jack Pines, leaving room for young pines to grow. This natural burn/rebirth rhythm created a constant churn of stands of young-growth Jack Pine perfect for the fussy Kirtland’s Warbler.

Then a series of unfortunate events occurred, like dominoes falling one after the other, and we almost lost this beautiful warbler forever.

Dan's Domino Theory of species imperilment and revival
(Spoiler alert: It's not all bad news.)

Domino 1, second half of the 19th century, the vast white pine and jack pine forests of the upper midwest are leveled. The wood is used for railroad ties and fences for growth in the great plains states, and for the 2"x10" rough-sawn timbers that form the floor joists in our Hyde Park brownstone.

Domino 2, in the first half of the 20th century, a strong effort is made to prevent forest fires in the few remaining stands of white and jack pines in Michigan's lower peninsula.

Domino 3, parasitic Brown-headed Cowbirds, who thrive in a mixed forest-prairie environment, move eastward, eventually into Michigan, where the red carpet has been rolled out for their expansion.

Domino 4, remaining jack pine forests of Michigan's northern lower peninsula mature. There are no stands of new-growth young jack pines, because their seed cones require the heat of forest fires to burst them open and release the seeds.

Domino 5, Kirtland's Warblers continue to return in spring to Michigan's jack pine forests, but they find fewer and fewer of the young-growth jack pines that they need for nesting. Those that do succeed in nesting find their nests parasitized by the newly-arrived Cowbirds.

Domino 6, by 1974 nesting bird surveys indicate that less than 200 pairs of Kirtland's Warblers remain.

Domino 7, Michigan DNR and other conservation stalwarts begin to take action. Controlled burns of mature jack pine stands create new breeding territory; trapping of Brown-headed Cowbirds helps level the playing field for nesting Kirtland's Warblers.

Domino 8, by 2011 there are 1,828 pairs of Kirtland's Warblers, and the species has even managed to establish nesting territories beyond the claustrophobic confines of northern lower Michigan.

Domino 9, now instead of potentially dangerous controlled burns, Michigan DNR and the forestry industry work hand in hand on a clear-and-plant strategy that provides wood chips for plywood production and a steady churn of young-growth jack pine stands for nesting warblers.

In this instance, the fallen dominoes spell "Success!"

Dan's Feathursday Feature is a regular contribution to the COS blog featuring the thoughts, insights and pictures of Chicago birder, Dan Lory on birds of the Chicago region.

Dan's Feathursday Feature: Kirtland's Warbler