December 12, 1876. Omaha Daily Republican 19(149): 2.
"Our Insect Enemies."
A Practical Communication from Professor Aughey.
Increase in the Number of Insects of Various Kinds - Birds as the Natural Enemies of Insects. - Interesting Statistics - Varieties of Insectivorous Birds - Spare the Birds and Get Rid of the Insects.
A New Game Law is Needed.
We have received from Professor Aughey the following and very suggestive and valuable paper embodying the results of his own observations, and some deductions therefrom which we think of great practical value. We trust that our contemporaries throughout the state will give it a place in their columns.
Our Danger and Our Remedy From Insects.
I wish to add some facts and suggestions to what the press has been saying on the subject of our danger from insects, and the remedy. There can be no question about the
Increase of Our Insect Enemies.
Even the chintz bug has been increasing, on the whole during the last ten years. I saw more butterflies of the army worm during the last summer than ever before in our history. It only requires a favorable season and conditions for this insect to become a formidable foe to our agriculture. Tree borers are also alarmingly on the increase. I noticed them in large numbers in groves during the last season, where they were never, to my knowledge, seen before. Many more instances of the same kind could be given. The vast number of grasshoppers that occasionally sweep down on our plains is too familiar to need discussion. it should be recollected, also, that the amount of damage done in a year, throughout the United States, by insects, is not less than four hundred millions of dollars, (Packard.) Illinois, alone has suffered to the amount of seventy-three millions in a single year. The poverty and starvation of settlements in Nebraska, produced by grasshoppers, is familiar to everyone; in fact these insect plagues bear most heavily on all the interests of the state.
We do not need to go far to ascertain the
Cause of This General Increase of Insects.
The balance of nature has been interrupted in Nebraska: Insects are increasing with the decrease of our insectivorous birds. This decrease of birds is traced directly to the agency of man. As a few persons still deny the agency of birds in keeping down insects, I will give a few examples from my note book. In May and June, 1875, I examined the stomachs of a great many prairie chickens which I had shot for that purpose, to ascertain definitely the nature of their food. No. 1 had 59 grasshoppers and 13 other insects in its stomach. No. 2 had 61 grasshoppers and 16 other insects and worms. No. 3 had 75 grasshoppers and nine other insects. Besides these insects there was a large mass of the same kind of materials that was too much macerated to be counted. The stomachs of quails contained from 40 to 50 grasshoppers and other insects, besides a large mass that could not be distinguished. In previous years when the migrating grasshoppers were not in the state the contents of the stomachs of these birds were still largely made up of various kinds of insects.
No families of birds are so little appreciated for their insectivorous qualities as plovers and snipes. They are represented in Nebraska by at least sixteen species. The number of insects which they destroy is enormous. I have found from thirty to forty-five insects and worms in the stomachs of one small species (Aegialitis semipalmatus). Many of these plovers and snipes spend the cold months in the gulf states, and come north in the spring to hatch. Formerly they were exceedingly abundant in this state, but they are now becoming reduced very fast by murderous hunters. Our thrushes, blue-birds, wrens, swallows, etc., all feed almost entirely on insects. The blackbirds and orioles that are charged with confiscating so many grains will be found, on examination, to make insects at least nine-tenths of their food. Now suppose that the
Insectivorous Birds Were Left to Increase
until there were about 1,000 to a square mile. Each bird, at a low calculation, would require 100 insects for food each day. This would destroy 100,000 insects each day on every square mile, and in a month 300,000,000 and in five months 15,000,000. But insectivorous birds really consume nearer 200 than 100 insects each day, and at this rate 500 such birds to the square mile would accomplish the same result. If birds are increased to the number proposed there will be insects enough to furnish them with food for many years. When once the insects become reduced in numbers, the birds, of the own accord, if left alone, take themselves to other regions. If they must be killed by carnivorous man, let the point of oversupply be first reached.
Destruction of Trees.
But let it be remembered that our forest and cultivated trees in Nebraska alone are preyed on by about 140 species of insects. Apple, pear and plum trees have about 100 species of insect enemies. Fifty species of insects interfere with grape culture. There are at least 35 insect enemies of our gardens. Most species of insects have a marvelous fecundity. One pair of grain weevils will produce 6,000 young between April and August. According to Reaumer, one aphide or plant louse (these aphides are found on almost all kinds of plants,) may become the progenitor in a single season of six thousand millions. The female wasp produces in one season, 30,000. (Packard.) The white ant deposits eggs at an average rate of sixty to a minute. Our own wild silk worm (Attacus cecropia,) which feeds so largely on our wild plum leaves, produces from 600 to 1,000 eggs per season. But I need not multiply these common instances of the enormous increase of insects. The entomologist whose eye is accustomed to look for insects sees almost every foot of ground in summer time swarm with life. If the naked eye does not see them the microscope brings them to view. No one need therefore fear that such an increase of insectivorous birds as is proposed would produce a famine among them, especially as more than half betake themselves to warmer regions on the approach of cold weather. The fact is we must get them or suffer immeasurably more in the near future from insect depredations than we have ever done in the past.
The Barbarous Killing of Birds.
But what hinders such a proposed increase of insectivorous birds? Every one knows that it is the barbarous custom of killing birds. No agent of destruction is so potent as bird dogs. They do immeasurably more damage that traps. When trapping birds was made illegal, hunting birds with dogs should also have been forbidden. The farmer is seldom able to hunt during the busy summer, and when he can go gunning on his own fields the young game has been so reduced in numbers and made so wild by men and dogs that little can be obtained. Better forbid by statute the killing of birds by any method for at least three years, and after that permit it only for a month by shooting without the aid of dogs. Dogs and traps should be eschewed for ever in Nebraska for hunting. The enforcement of such a law would work unspeakable good to Nebraska. Surely sporting-men will, for the sake of the public good, be willing to abandon their favorite amusement. The objection is sometimes made that a large increase of prairie chickens and quails would be
Endangering to the Crops
of the farmers. I believe that is a mistaken view. In examining the stomachs of these birds that were killed in wheat stubbles after harvest, I almost invariably found more insects than grains of wheat. The only exception to this experience was the occasional finding of an almost exclusive meal made on prairie grass seeds and berries. But surely the few seeds and grains that they confiscate will not be grudged to them in view of the many insect enemies which they destroy.