Sunday, August 4, 2013

Letters to the New England Farmer #4. Insectiverous Birds

The last letter we will look at from the New England Farmer of the 1820s, was credited to "F---" from Danvers, MA, and published on July 25, 1828. It was titled, "Insectiverous Birds." [This was an acceptable alternative spelling during this era]. It is noteworthy because it explicitly referenced two texts of great influence in the formation of economic ornithology--from Alexander Wilson and Richard Bradley. The impetus for the letter was a familiar one: the canker worm.
Mr. Fessenden--I have noticed in your New England Farmer several accounts of the ravages of the canker worm this season. And I am inclined to believe this insect, as well as some others, has been more numerous in the county of Essex this season than for many years. Now, Mr. Editor, we are told by many people, we must tar our trees and do many other things to reserve our orchards from the ravages of the canker worm, which, after all, it avails but little. The insect increases in number yearly.
The solution, also familiar by now: small singing birds. But this time the author wielded the authority of an ornithologist:
But for my own part, I think, were we to leave off wantonly destroying our small SINGING BIRDS, we should be less troubled with insects of all kinds. It is a fact well known to every naturalist, that small birds destroy an almost incredible number of noxious insects. The amiable and indefatigable ornithologist, ALEXANDER WILSON, who perhaps was better acquainted with the habits of our birds than any other person, when speaking of the Sturnus Predatorius, or red-winged black bird, which, by the way, is by our farmers considered the most mischievous of birds, says 
The author went on to quote Wilson at length on the red-winged blackbird, with special attention to Wilson's speculative count of vermin destroyed by the species in the United States:
"their food in spring and the the early part of summer consists of grub-worms, caterpillars, and various other larvae, the silent but deadly enemies of all vegetation, and whose secret and insidious attacks are more to be dreaded by the husbandman than the combined forces of the whole feathered tribe together, for these vermin the blackbirds search with great diligence; in the ground at the roots of plants, in orchards and meadows, as well as among buds, leaves and blossoms; and from their known voracity, the multitudes of these insects which they destroy must be immense. 
Let me illustrate this by a short computation. If we suppose each bird, on an average, to devour fifty of these larvae in a day (a very moderate allowance) a single pair in four months, the usual time such food is sought after, will consume upwards of twelve thousand. It is believed that not less than a million pairs of these birds are distributed over the whole extent of the United States in summer; whose food being nearly the same, would swell the amount of vermin destroyed to twelve thousand millions. But the number of young birds may be fairly estimated at double that of their parents, and as these are constantly fed on larvae for at least three weeks, making only the same allowance for them as the old ones, their share would amount to four thousand two hundred millions; making a grand total of sixteen thousand two hundred millions of noxious insects destroyed in the space of four months by this single species. The combined ravages of such a hideous host of vermin would be sufficient to spread famine and desolation over a wide extent of the richest and best cultivated country on earth. 
All this, it may be said, is mere supposition. It is, however, supposition founded on known and acknowledged facts." 
From Wilson's supposition, the author moved onto Bradley's supposition (nevertheless, "founded on actual observation.") 
Mr. Bradley, in his General Treatise on Husbandry and Gardening, shows "that a pair of sparrows, during the time they have their young ones to feed, destroy on an average (every week) about three thousand three hundred and sixty caterpillars." This calculation he founded on actual observation. And it is well known that several kinds of our birds, such as the hirundo [swallow], musicopa genera [flycatchers], and some others, feed entirely on insects.
Thus it was, at least in theory, possible to precisely calculate the damage done by wanton shooting parties.
I am fully persuaded, as long as farmers and others permit boys to roam over their fields and shoot down every small bird they meet--as long as young men are in the habit, on our anniversaries, of forming themselves into shooting parties, for the purpose of destroying small birds, which they do in immense numbers--I say as long as this wanton destruction of birds is carried on, we must expect innumerable hosts of noxious insects will continue to commit depredations on our orchards, our fields, and our gardens. 
Alexander Wilson's work, as we will soon see, had become affordable and was widely circulated during this era. The reference to Richard Bradley, on the other hand, is a bit more surprising. The specific passage referenced by "F---" can be traced to the "common sparrow" entry in Bingley's Animal Biography, and may have travelled via other publications copying from Bingley before "F---" read it.
I will do my own speculation here and wonder if "F---" wasn't Samuel P. Fowler (1800-1888), the prominent naturalist, who would later write articles about birds for the New England Farmer under his own name. 

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