Date: 9/15/20 7:03 am From: Chuck Otte <cotte...> Subject: Re: Migratory birds dying in large numbers in the West
I routinely receive questions at my office when people find dead birds(s) in their yard. It seems like the default assumption by many folks is disease. Sometimes it is but we seem to see those sorts of things (from my un-researched perspective) far more often in waterfowl due to the sheer numbers that are often congregated. People are also often prone to try to associate the most current mega-event with the demise of the birds. Last week people were reporting dead birds with the cold weather (here in Kansas) and snow further west. "Well, the birds must have froze to death!" is the immediate response. Birds do freeze to death, but, as someone said here or elsewhere, let's also look at their food sources or lack there of. Many of these species can only last a day or two or three without food. Insect eaters were in serious trouble last week because with constant rain and drizzle and several days of temperatures below 50, there weren't many flying insects around. Species that are foliage and bark gleaners were bound to fare better than those that really rely on flying insects. Eastern Phoebe vs Eastern Wood-Pewee comes to mind as well as all the swallow species. Hummingbirds survive well into very cold weather if they can find a source of nectar but eventually the lack of insects, i.e., protein, becomes an issue.
The devastating fires to the west are certainly causing air quality problems for birds as well as humans (think of the canary in the coal mine) but smoke will also relocate insects, drive them away or greatly impact their existence. The story out of New Mexico over the past few days is going to be interesting to watch as they examine the birds "falling from the sky". I'm just willing to bet that lack of nutrition will strongly figure into this.
And if it is lack of insects we probably need to look at more than just fires for the cause. Pesticides and large scale landscape changes can have a major impact. I just read the most recent Kansas School Naturalist from Emporia State University yesterday. The subject was "Rock Mountain Locust: the Insect That Defined the West". This was the grasshopper species that had mega-swarms of billions of insects in the 1870s that moved into the Great Plains and beyond eating everything in sight. Yet in an era before pesticides (as we know them today) and major climate change, was extinct by 1903. It is generally felt that conversion of the south central/southwest Colorado valleys from grasslands to farmland following the 1870s destroyed the heart of the breeding area creating an ecological bottleneck that it couldn't recover from. The paper postulizes that the extinction of this insect likely had ripple effects on other species including the now likely extinct Eskimo Curlew. The web of life is very real and humans need to wake up to the fact that the canary in the coal mine is in serious trouble!
My two cents worth.
----- Chuck Otte <cotte...> County Extension Agent, Ag & Natural Resources Geary County Extension Office, PO BOX 28 785-238-4161 Junction City, Kansas 66441-0028 FAX 785-238-7166 http://www.geary.ksu.edu/