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Gone to the Birds
Article #360 July 2024
By Bill Cook

Watching birds continues to be one of the favorite activities in the United States.  For whatever set of reasons, humans are fascinated by our flying fauna.  For some folks, the interest dives deeper than the casual “oh my”.

          Forest management is one of the greatest friends to bird populations.  Does that sound a bit biased coming from a forester and wildlife biologist?  Well, perhaps it is.  Yet, forestowners interested in bird habitat can do much to swing habitat one way or another with bird populations in mind.
          Michigan sports about 250 species of birds, not counting another 60 or so accidentals that occasionally blow-in from the Rockies, the Canadian tundra and taiga, or one of the oceans.  Of the 250 species, roughly half prefer forested habitats.  The other half tend to occupy grasslands, open brushlands, and aquatic habitats. 
          Identifying a single preferred habitat can sometimes be a bit of a head-scratcher, as many birds will use more than one habitat.  So, while there may be shades of the arbitrary in the classification, such groupings help us better understand the requirements of our avian friends. 
          What sorts of forest conditions do birds seek?  In fact, diversity reigns across our Lake States forests, and that is quite a good thing, especially if you’re a bird.  Consider the following: conifers versus deciduous, age classes ranging from regeneration to young to mature to old, lowland versus upland trees, open versus closed canopies, edges between different habitats, the presence of streams and openings, and the list goes on. 
          To make matters more complicated (and better), these conditions change over time.  Bird populations move around their geography to find, and fight for, their favorite turf.  Some spend most of their time high in the canopy, others in the subcanopy, others yet on the ground. 
          Then, many birds are migrators that use our northwoods as “baby bird factories”.  After fledging the chicks, and food resources dwindle in the fall, nearly everyone flies south for the winter.  Some travel as far as the southern parts of South America.  Interestingly, there are even a handful of bird species that arrive from further north to spend the winter here.  Birders get mighty excited if the Great Gray Owls arrive. 
          However, we do have our year-round residents such as chickadees, grouse, woodpeckers, and nuthatches.  They have adapted to exploit what food sources the winters have to offer. 
          Forest management changes the age and structure of the forest.  Take the famous Kirtland’s Warbler, who loves jack pine.  However, the jack pine cannot be too old or too young, not too dense or not too sparse.  Finding that “just right” set of breeding conditions was increasingly difficult, resulting in the warbler’s placement on the endangered species list.  However, with decades of purposeful forestry, the bird is no longer listed as endangered. 
          Groups of bird species that occupy similar neighborhoods are called “suites”.  Each suite often has a representative prominent or key species.  These designations help humans relate to a suite.  For example, the brilliant Blackburnian Warbler occupies the high canopy of dense forests.  Alternatively, the Ovenbird is a ground nester under a dense canopy.  Cooper’s Hawks favor the mid-canopy for nesting. 
          Young forest habitats, and their associated birds, have become increasingly uncommon.  The Golden-winged Warbler is the poster child for this habitat.  Its population numbers have dwindled.  In response, biologists work to provide more young forest, often in the form of regenerating clearcuts. 
          Areas with grasslands and brush thickets are also less common, as they are regarded as “wastelands” prone to human development.  The Yellow Warbler hangs-out in such places.  While far from threatened, their numbers have been steadily declining. 
          Forestry practices can be used to build-up a mid-canopy structure of saplings and tall brush species.  The “green wall” under the canopy is favored by a wide range of birds.  Gaps cut into the forest, and edges between forest age classes are also particularly rich habitats for birds.  For the most part, traditional forestry has been good for birds, especially in wider landscape settings. 
          Red pine stands are sometimes decried as “biological deserts”.  However, Pine Warblers and Red Crossbills will beg to differ.  Turkeys will roost in mature pine.  Hawks find the open understory easier places to grab mice.  Red pine stands among an ocean of hardwoods provide an important piece of community diversity.  While sometimes inherently low in the number of bird species at some stand ages, red pine remain important forest components. 
          A range of forest composition and structure builds the keystone for bird diversity.  It’s a game across the landscape and over time.  Forest management can help bolster populations of struggling bird species.  However, our northern breeding habitat is only one element in the habitat needs of migrators.  Even if we provide the best summer habitat, a species may not benefit if their winter habitat is threatened. 
          To learn more about birds, the “Merlin” app for your phone is a tremendous resource.  The software has gotten rather good at hearing bird songs and letting you know who makes them, and then provides information about sight identification, habitat, and life histories.  It certainly shortcuts the pathway to more satisfying bird-watching. 
          For more about forestry modifications, browse the title “Forestry for Michigan Birds”.  A pair of guidelines were prepared through the American Bird Conservancy, one of for forestowners and a second for forest managers.

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Canada Warbler	Cooper's Hawk	Indigo Bunting	Pileated Woodpecker	Rose-breasted Grosbeak	Towhee