Birds, Symbols of Peace and Hope, Are Leaving Town

Do you still see nuthatches nesting in your backyard birdhouse?  Most of us don’t.  Summers are just getting too hot to raise their young.  The nuthatches still winter in and around Redding, but most of them have moved north to nest, and we’re on track to lose them completely around mid-century.

          And they’re not the only ones.  Among the most familiar birds that have lived here since pre-Columbian times, acorn woodpeckers, yellow-billed magpies, juncos, bushtits, white-crowned sparrows, and chickadees are all expected to be gone or in retreat from our area in the coming decades.  The iconic Redding bald eagles, who this year lost their chicks to heat and dehydration, will no longer be able to nest here.  In all, of 214 Shasta County bird species studied, Audubon lists only 64 as stable in the face of current and coming climate change.

          Unfortunately, the departure of these birds is not only a loss to the biology and beauty of our area.  When these birds move to a new place, they must encroach on the natives there.  They compete for food and nesting sites; someone is inevitably diminished.  Sometimes the climate refugees are directly predatory.  Ravens are increasing in the Far North where they feast on the eggs and young of ducks and shorebirds nesting on the open tundra.  There is no Farther North for those arctic nesters to flee to.

          Beyond killing with dehydration and forced relocation, increasing heat affects birds in many subtler ways.  Fire can create habitat, but smoke and repeated large fires can also destroy it for the couple seasons that mark a whole generation for the birds who lived there.  The adults may survive; they just don’t reproduce.

Some birds seasonally migrate based on day length, while the plants and insects they need react to temperature cues.  So, the caterpillars a tanager normally feeds to its young may already be too big and tough for their nestlings to eat by the time they hatch.  The young starve, or the parents instinctively recognize the problem and don’t even try to nest.

Warm conditions and reduced snow can keep deer and elk in the high mountains, browsing longer on alpine willow thickets, reducing those rich nesting and feeding sites for the numerous warblers and sparrows who would use them.  Again, it is nesting that suffers.

Insects that ride the heat can bring new diseases.  West Nile virus and avian flu have not only decimated some wild birds but also domestic stock, and in some cases infected humans directly.

Despite news coverage, It is fairly easy for us to disregard these cues about a drastically changing world.  Most of us don’t have backyard birdhouses where we see changes in nesting activity.  Most of us don’t raise chickens; their avian flu die-off means higher grocery prices, not a grisly backyard scene.  We live indoors, and keep our children indoors as the outside becomes less hospitable and screentime more engulfing.  A degree of temperature rise means a bigger AC bill, but it doesn’t mean biological mayhem.

Except that it does.

The birds are experiencing an environmental hazard, just as they did in coal miners’ tunnels not so long ago.  The sooner we leave the mining the better off both the birds and we will be.