by Denny Olson
Fifty years ago this month, I was well on the way to becoming a biologist. I was learning about populations of wildlife, complex food webs, natural selection of the fittest, and the oppositional pressures of reproductive rates versus carrying capacity. That last concept was especially fascinating, because it made perfect sense to me that at some place, animals that had populations higher than the food-water-shelter-space supply had always crashed by some direct or indirect means. There were thousands of examples — and literally no exceptions, to the established theory — “theory” being the highest order of amassed evidence, as close to “truth” as any scientist dares to admit.
Along came the first Earth Day on April 22nd, celebrating and warning about the wonderful balance of our planetary life systems, and the potential tragedy of immutable biological “theory”. Limits to Growth by the Club of Rome was published, getting their numbers and predictions far too alarmist, and lulling the powers-that-be into complacency. But, with the advent of Earth Day, surely the world would pay attention from there forward.
That relative complacency has lasted almost exactly fifty years. The biologists, ecologists and climate scientists started paying attention in the latter half of that half-century, watched the polar ice melt every year, and fretted about polar bears, changing weather patterns, rising seas, and all of the complications thereof. But, like the politics of the times, scientific findings and their champions were seen as yet another argument from an entrenched group with opinions, along with liberals, conservatives, moderates, libertarians, evangelicals, and certifiable conspiracy whackos. Belief was what mattered, whether evidence-based or not.
Just lately, we have looked at 140 million pieces of citizen-science evidence (Breeding Bird Surveys since 1967), and surmised that the 10 billion birds that resided or arrived in the North American Spring, and the 20 billion that left in the fall after breeding — have shrunk by 29% since that first awareness-raising Earth Day in 1970. These are the birds that spread our seeds, pollinate our trees and flowers, are first responders to all of our animal corpses, warn us about our poisons, and eat 500 tons of insects every year. They are clearly a critical cog in our own life support system.
So what are the reasons behind the reasons? According to the US fish and Wildlife Service scientists, in decreasing order of importance: 1) habitat loss (the big one,) 2) cats (90 million domesticated and another 90 million feral and stray), 3) flying into buildings, 4) vehicle collisions, 5) poisons , 6) collisions with electrical lines, 7) collisions with communication towers, 8) electrocutions, 9) oil pits, and 10) collisions with wind turbines (Yup, only one reason behind the reasons. Humans. Understatedly, it seems that we are somewhat responsible for the carrying capacity limiting factors on the populations of birds.
Another Audubon study using some of the same data, plus hundreds of other studies, now projects that here in the Flathead, Great Gray Owls, Boreal Owls, White-tailed Ptarmigan, Spruce Grouse, Black Swifts, Bobolinks, Pygmy Nuthatches, Gray-crowned Rosy Finches, American Pipits, Boreal Chickadees, Barrow’s Goldeneyes, and Townsend’s Solitaires will be gone from nesting populations in 2100. Forty-nine other species are projected as highly vulnerable to the habitat loss from a 3-degree C. rise in global temperatures in the next 80 years (we have risen 1 degree already). Sixty-three other species are projected moderately vulnerable.
We stand by, observing our shrinkage of the carrying capacity of the world’s birds. We feel bad, of course, and grateful that it is them and not us. Good thing those pesky biological principles of carrying capacity don’t apply to us, we think, hugging our packages of toilet paper, sequestered at home in a world-wide pandemic …
One other thing about biologists and their “theories”. We sometimes hate it when we are right.