Have you ever seen a blackpoll warbler? If you have, unless you are familiar with warblers, you may have mistaken it for a chickadee.
From this picture (from All About Birds), and the one below (same site, different page), you can see that they are similar. The warbler's body is strongly patterned, while the body of a black-capped chickadee is more uniform in color. We notice the black cap with a broad white lower face on both birds. They are so active, we seldom have time to see the differences.
But they don't sound the same. The chickadee is named for its call, which we often "spell" as "chick-a-dee-dee-dee-dee". The warbler's call is a series of very short, quick notes about an octave above the highest note on a piano.
Their migration habits differ dramatically. Chickadees don't migrate, except in the extreme north or south portions of their breeding range. Blackpoll warblers migrate 5,000 to 6,000 miles (8,000 to 10,000 km), each way, every year.
Both are endurance champions, just in quite different ways. Both are very small birds; a blackpoll warbler weighs 14-15 grams (~0.5 oz) most of the year and a black-capped chickadee weighs a little less at 11-12 grams (~0.4 oz). Except in the far northern reaches of its range, a chickadee stays year-round, braving winters that, in my experience living in Ohio, are about as miserable as I can imagine. The warbler, along with most warbler species, is a snowbird. I winters in the tropics and summers in or near the Arctic. Actually, our term ought to be "anti-snow bird"!
In Kenn Kaufman's new book A Season on the Wind: Inside the World of Spring Migration, he describes a blackpoll warbler's yearly trek at length. A condensed version:
The spring migration is less of an ultra-marathon and more a series of medium-length "hops". Beginning from a winter range in Venezuela or Brazil, a bird destined to nest near Denali or Nome, Alaska flies a few hundred miles to the northern coast of South America. There it rests a day or so and fattens up for a crossing of the Caribbean, which it crosses by island-hopping until it reaches Florida. The next hop may be to Georgia or thereabouts. Then it fattens up for a longer trek, nearly nonstop to western Alaska. The winter migration is a pair of ultra-marathons. The bird begins by crossing North America, which takes about three days of nonstop flying, until it reaches New England, perhaps Massachusetts. There, it eats until it weighs about a full ounce (28 grams or more). Then it flies south, out to sea, not to see land (except perhaps Bermuda in the distance) until it reaches the coast of Venezuela, weighing less than half what it did just four days earlier.
Every living blackpoll warbler is descended from ultramarathon champions! They are not the only ones. Hundreds of species of birds, many no larger than your thumb, yearly migrate hundreds to thousands of miles. Just in body-length terms, it would be like me (a six-footer) traveling halfway to the moon and back, every year…if there were somewhere halfway to the moon to stop for a few months.
One matter the author takes up in the book is the notion of "flyways". For ducks and other water birds, there do seem to be "highways in the sky" that they tend to follow. Not so for other birds. Recent technology shows this dramatically. Here is a national radar image from NEXRAD taken in May of 2016:
NEXRAD (Next generation radar) was developed to see rainfall. Birds are lots bigger than raindrops, so they are easily seen. As it happened, there were several large storm systems over the central and eastern U.S. that day. One stretches from southern Texas to eastern Nebraska, another just east of the Mississippi River into Indiana, and a smaller series of storms from Florida north to North Carolina. These all show up as green, yellow and red. The blue blotches with green centers show where the birds are during their spring migration. The black areas between blue blotches are areas not covered by the radar. The birds are spread out over the whole area; there are very few concentrations. One is visible at Lake Erie in northern Ohio. From about Cleveland, around the shore of Lake Erie to Toledo, birds that don't wish to cross the lake turn west and fly around it. If there are any "songbird flyways", this area is one of them. Its western portion is not covered by NEXRAD, so it isn't as prominent in this image as it ought to be.
A decade ago or so Mr. Kaufman moved from Arizona to Ohio, not far from the Magee Marsh refuge (and premier bird-watching boardwalk). The book focuses on events of a few springtime migration seasons. From the big eagles, vultures, and hawk, to blue jays, to little vireos and tiny warblers, hundreds of species of migrating birds fly through and stop over at or near Magee Marsh in the springtime. The author's lyric descriptions of these marvelous creatures and their travels are utterly captivating.
Here and there throughout the narrative, he tells the tale of a struggle he and his colleagues in northwest Ohio undertook to prevent the construction of an "experimental" wind turbine, right in the middle of the area, on a military reservation. It's worth considering just how dreadful big windmills can be for migrating birds.
A 2-megawatt turbine has a rotor about 90 m (~300 ft) in diameter, with three blades, atop a tower that places the top of the swept circle as high as 180 m (~600 ft). A stiff breeze of 20 m/s (~45 mph) is about midway in a turbine's power curve. When the wind is this speed aloft, it is about half that speed or less near the ground. In this breeze the blades rotate at 16 rpm, with a blade cutting through the air 48 times per minute, or about every 1¼ seconds. In that slice of time, a parcel of air 25 m long passes through the blades. For big birds like eagles soaring on this wind, there's one chance in 15 of getting hit by a blade. The speed of the blade tip is 75 m/s or 170 mph. They can't see it coming in time to react. For a duck-sized bird, the chance of getting hit are one in 35, and for a tiny warbler, "only" one in 165. But while only a few eagles pass along the Lake Erie shore daily, and a few dozen ducks, tens of thousands of warblers and other small songbirds do so, up to a few million each season. The daily "catch" of small birds can be hundreds. Not only so, one wind farm reported that more bats were being killed than birds. Think about this: every bat eats from 100 to 1,000 mosquitos and similar insects every day. How many can we afford to wipe out? There is one wind farm in California that is known to kill 100 golden eagles every year. Whatever happened to the Endangered Species Act? Big money, that's what.
Sadly, wind turbines aren't as eco-friendly as they are billed, and not just because they kill birds and bats. A big turbine contains a lot of metal, both steel and aluminum, which required a huge amount of energy to produce, and the coke (refined coal) needed to make the steel resulted in the release of a great amount of CO2. What holds up a big turbine? Many tons of steel-reinforced concrete in a hole the size of a garage. How does the turbine get moved into location? Several trucks per turbine, driving hundreds of miles. Much of the energy needed to produce the metals, particularly the aluminum, comes from hydroelectric dams along the Columbia River. So I have called the wind turbine industry "a scheme for turning hydropower into aluminum and steel, moving it across the country, and turning the metals back into electricity…at a net loss." A turbine has a finite lifetime. I have yet to see a full econometric analysis of wind turbines that demonstrates how you get more out than you put in. If every bit of energy used for the mining, refining, manufacturing, transportation, erecting, and operating of every wind turbine was required to be derived exclusively from wind power, I think the whole enterprise would shrink away to nothing in pretty short order.
Just by the way, now that solar cells are routinely produced that exceed 15% efficiency, the industry is operating at a net energy gain. We ought to be pushing for more solar, and leaving the wind to the birds.
The turbine project on the military base that the author and others were working against was eventually cancelled. Good news, temporarily.
I lived in Sandusky, Ohio during my high school years. One spring morning I was up early, and I hung a microphone out the window to record the dawn chorus. I wish I still had the tape. It was amazing and glorious. At the time I knew nothing about bird migration. I had no idea that I was living right along a concentration of migrating birds like none other. I could recognize no more than five or six bird calls (robin, chickadee, crow, jay, and hawk, at least). But I could tell that the morning birdsong had at least fifty species of singers contributing. Even if I didn't know what they were, I could tell one from another.
I hope Mr. Kaufman's books reach a wide audience. The more of us who care about wildlife, including birds, the more likely that youngsters a generation or three in the future can wake up to a morning chorus as glorious as the one I remember.
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