Oats,70,800sq. miles.Wheat,81,600sq.miles.Hay,109,400sq. miles.Miscellaneous.Roots, cotton,tobacco, etc.,168,600 sq. m.Excessive.Maize,Indian corn,226,600sq. miles.Wheatforexport,143,000sq. miles.Arable land unassigned1,200,000 square miles.Deduct for cities, towns, parks, and reserves of all kinds200,000squ"re m"iles—————Reserve for future use1,000,000squ"re m"ilesForest, mountain, arid, etc., not counted, about 1,000,000 square miles,not included in these lines or squares.
No reduction on area cultivated on prospective improvement in the present methods of farming, although it may be assumed that the prospective increase of crop per acre will exert great influence.
No reduction on area cultivated on prospective improvement in the present methods of farming, although it may be assumed that the prospective increase of crop per acre will exert great influence.
If the facts should be in 1930 consistent with Mr. Hyde's "speculation" it would therefore appear that our ability to meet the domestic demand of 1930 with proportionate export of cattle, provisions, and dairy products, and to set apart a little patch of land for the export of 1,226,000,000 bushels of wheat raised at the rate of only13.4 bushels per acre from 143,000 square miles of land will be met by the cultivation of not exceeding 700,000 square miles out of 2,000,000 available.
I should not venture to question the conclusions emanating from the Department of Agriculture, or the deductions of so eminent a scientist as Sir William Crookes, had I not taken the usual precaution of a business man in studying a business question. I went to the men who know the subject as well as the figures on which statistics are to be compiled.
Being supplied by the Popular Science Monthly with one hundred proofs of the first nine and a half pages of the December article in which the terms of the problem are stated, I sent those proofs to the chiefs of the experiment stations and to the secretaries of agriculture in all the States from which any considerable product of wheat is now or may be hereafter derived; also to many makers of wheat harvesters; to the secretaries of Chambers of Commerce, and to several economic students in the wheat-growing States. This preliminary study was accompanied by the following circular of inquiry:
Boston, Mass.,October 5, 1898.To the Chiefs of the Agricultural Experiment Stations and others in Authority:Calling your attention to the inclosed advance sheets of an article which will by and by appear in the Popular Science Monthly, I beg to put to you certain questions.If the matter interests you, will you kindly fill up the blanks below and let me have your replies within the present month of October, to the end that I may compile them and give a digest of the results? I shall state in the article that I am indebted to you and others for the information submitted.Area of the State of....................... square miles.1. What proportion of this area do you believe to be arable land of fair quality, including pasture that might be put under the plow?Answer ................... square miles.2. What proportion is now in forest or mountain sections which may not be available for agriculture for a long period?Answer ................... square miles.3. What has been done or may be done by irrigation?.................................................................... .................................................................... ....................................................................4. What proportion of the arable land above measured should you consider suitable to the production of wheat under general conditions such as are given in the text, say, a stable price of one dollar per bushel in London?Answer ................... square miles.5. To what extent, in your judgment, is wheat becoming the cash or surplus crop of a varied system of agriculture as distinct from the methods which prevail in the opening of new lands of cropping with wheat for a term of years?.................................................................... .................................................................... ....................................................................What further remarks can you add which will enable me to elucidate this case, to complete the article and to convey a true impression of the facts to English readers?.................................................................... .................................................................... ....................................................................Your assistance in this matter will be gratefully received.Respectfully submitted,Edward Atkinson.
Boston, Mass.,October 5, 1898.
To the Chiefs of the Agricultural Experiment Stations and others in Authority:
Calling your attention to the inclosed advance sheets of an article which will by and by appear in the Popular Science Monthly, I beg to put to you certain questions.
If the matter interests you, will you kindly fill up the blanks below and let me have your replies within the present month of October, to the end that I may compile them and give a digest of the results? I shall state in the article that I am indebted to you and others for the information submitted.
Area of the State of....................... square miles.
1. What proportion of this area do you believe to be arable land of fair quality, including pasture that might be put under the plow?
Answer ................... square miles.
2. What proportion is now in forest or mountain sections which may not be available for agriculture for a long period?
Answer ................... square miles.
3. What has been done or may be done by irrigation?
.................................................................... .................................................................... ....................................................................
4. What proportion of the arable land above measured should you consider suitable to the production of wheat under general conditions such as are given in the text, say, a stable price of one dollar per bushel in London?
Answer ................... square miles.
5. To what extent, in your judgment, is wheat becoming the cash or surplus crop of a varied system of agriculture as distinct from the methods which prevail in the opening of new lands of cropping with wheat for a term of years?
.................................................................... .................................................................... ....................................................................
What further remarks can you add which will enable me to elucidate this case, to complete the article and to convey a true impression of the facts to English readers?
.................................................................... .................................................................... ....................................................................
Your assistance in this matter will be gratefully received.
Respectfully submitted,Edward Atkinson.
To this circular I received twenty-four detailed replies, containing statistics mostly very complete; also many suggestive letters, in every case giving full support to the general views which I had submitted in the proof sheets. It has been impossible for me to give individual credit within the limits of a magazine article to the gentlemen who have so fully supplied the data. Space will only permit me to submit a digest of the more important facts in a table derived from these replies:
Name.FROM RETURNS MADE TO MY INQUIRY.From UnitedStates reportin wheat,1897.Area of State.Arable.Suitable towheatMinnesota84,28766,00050,0007,189South Dakota76,00042,50040,0004,187North Dakota74,31250,00050,0004,300Illinois56,00054,00020,0002,292Missouri68,00064,00064,0002,448Wisconsin56,00035,00035,000961—————————————————————414,599311,500259,00021,372======================================Texas269,694200,000100,000700California158,36054,00030,0005,062Montana145,31030,00025,000109Idaho87,00030,00015,000192—————————————————————660,364314,000170,0006,063======================================Total1,074,963625,500429,00027,435
I do not give the data of the Eastern and Southern States, and I have selected only the most complete data of the other States, choosing the more conservative where two returns have been made from one State.
The foregoing States produced a little over one third of the wheat crop of 1897. They comprise a little over one third the area of the land of the United States, excluding Alaska.
The list covers States like Illinois, Minnesota, and Wisconsin, now very fully occupied relatively to Texas, Montana, and Idaho, as yet but sparsely settled.
Ohio, Michigan, Indiana, Iowa, Kansas, Nebraska, Oregon, and Washington combined far exceed the above list in wheat production; but, as I have no complete data from these States, I can only say that the national or census statistics, as far as they go, develop corresponding conditions to those above given. The very small product of Texas and Montana, even of Idaho, as compared with the claimed potential, will attract notice, and perhaps excite incredulity. But let it be remembered that in 1880 the Territory of Dakota yielded less than 3,000,000 bushels of wheat, while in 1898 the two States of North and South Dakota, formerly in one Territory, claim to have produced 100,000,000 bushels. Perhaps it will then be admitted that the potential of Montana, and even of Idaho, may be attained in some measure corresponding to the reports from those States; but as yet their product is a negligible quantity, as that of Dakota was only twenty years since.[9]
Again, let it be remembered that Texas will produce a cotton crop, marketed in 1898-'99, above the average of the five ante-war crops of the whole country, and nearly equal to the largest crop ever grown in the United States before the war. Texas could not only produce the present entire cotton crop of the United States but of the world, on but a small part of her land which is well suited to cotton. When these facts are considered, perhaps the potential of that great State in wheat and other grain, in cattle and in sheep, as well as in cotton, may begin to be comprehended.
The writer is well aware that this treatment of a great problem is very incomplete, but it is the best that the leisure hours of a very busy business life would permit. If it discloses the general ignorance of our resources, the total inadequacy of many of our official statistics, the lack of any real agricultural survey, and the necessity for a reorganization and concentration of the scientific departments of the Government as well as of a permanent census bureau, it will have served a useful purpose.
If it also serves to call attention to the meager average crops and the poor quality of our agriculture as a whole down to a very recent period, it may suggest even to those to whose minds the statistics of the past convey but gloomy and "doubtful views" of the future, that the true progress in scientific agriculture could only begin when substantially all the fertile land in the possession of the Government had either been given away or otherwise distributed. So long as "sod crops" and the single-crop system yielded adequate returns to unskilled farmers, no true science of agriculture could be expected, any more than a large product of wool can be hoped for in States where it has been wittily said that "every poor man keeps one cur dog, and every d—d poor man keeps two or more."
Finally, if I shall have drawn attention to the very effective work which is being done in the agricultural experiment stations by men of first-rate ability, I shall have drawn attention to a great fact. This work has already led to a complete revolution from theold practice of maltreating land, and to the renovation of soils that had been partially exhausted. Governor Henry A. Wise, of Virginia, long since condemned the old methods of Southern agriculture by telling his hearers, "The niggers skinned the land and the white men skinned the niggers." We are changing all that by new and progressive methods. I hope that in this recognition of the work of the experiment stations I shall have made some return for the attention which has been given to my inquiry by so many of my correspondents that the space assigned me forbids a list of my authorities being given by name.
When the suggestion is made from the Department of Agriculture that all that science has yet accomplished has been to stop a tendency to a lessened production from the land now under the plow, and when it is even suggested that in 1930 the present meager average of crops per acre may still exist, it seems to me that little credit is given to the good work already accomplished in the short period in which the separate Department of Agriculture has been represented in the Cabinet, especially in the last five or six years, while the suggestion itself shows very little consideration of the great work of the experiment stations.
Unless it can be proved that my correspondents and myself have entered into a conspiracy to mislead the public in dealing with the potential of this country in wheat production, nearly all the deductions from the figures of the past must be considered mere statistical rubbish. These statistics cover sections and States in which wheat should never be grown or attempted in competition with the true wheat soils and climate. As well might misplaced iron furnaces, built to boom city lots where there are no favorable conditions for the production of iron, be included in an average and held up as a standard of our potential in iron and steel production.
In my efforts to discover the rule of progress in the arts and occupations of the people of this country, it has become plain that in ratio to the application of science and invention to every art the quantity of product is increased, the number of workmen is relatively diminished, the price of the product tends to diminish, while the wages or earnings of those who do the work are augmented. I have investigated many branches of industry, and find evidence conclusive to my own mind that such is the law of industrial development. This rule is subject to temporary variations under the restriction of statutes. In my own judgment, the so-called protective principle or policy of interference with commerce by imposing fines on foreign imports has retarded the progress of the specially protected arts, and has in some measure obstructed the diversity of manufactures; but the opposite policy of absolutely free trade inour domestic traffic over a greater area and among a much larger number of people than have elsewhere secured their own liberty has been so much more potent in its progressive influence as to have lessened the evils of the restrictions on foreign trade.
According to my observation, all the efforts to regulate railroad charges by State legislation and under the interstate commerce act have greatly retarded the progress of the railway, and have deprived great States, notably Texas, of any service at all commensurate to the demand which might otherwise have been supplied to the mutual benefit of the owners of the railways and the inhabitants of the State. The most serious retarding influence, especially evil in its effect upon farmers, was the useless panic of 1893, caused by the silver craze—that is to say, by the effort to enact a force bill by which the producers of our great crops would have been compelled to accept money of half the purchasing power of that to which their industry had been long adjusted. This caused a temporary paralysis of industry, in which I think none suffered so much as the farmers of the country.
But admitting these temporary variations, I find the same rule governing the products of the farm that governs the mine, the factory, and the workshop—namely, a lessening of the number occupied in ratio to the product; a great reduction in the cost of labor; an increased return in due proportion of the skill and intelligence of the farmer; a rapid reduction in the farm mortgages, ending at the present date in making the farmers of the grain-growing States the creditors of the world, especially those occupied upon wheat.
But in the development of this progress we find the reverse of the practice in the factory and the workshop. The most important applications of science and invention led first to what might be called the manufacture of wheat on an extensive method of making a single crop on great areas of land. That phase has about spent its force; the great farms are in process of division; the single-crop system has about ended; the intensive system of making a larger product from a lessened area with alternation and variation in crops is rapidly taking the place of former methods.
Therefore, while many branches of manufacturing tend more and more to the collective method, the tendency in agriculture is more and more to individualism in dealing with the land itself, coupled with collective ownership in the more expensive farm machinery, in creameries, cheese factories, and the like. We are apparently at a halfway stage in this revolution of agriculture. The intelligent and intensive methods of breeding cattle and sheep is also rapidly taking the place of the semibarbarous conditions of the ranch.
If these points are well taken, the very suggestion that we must compute the land which should be under the plow in 1890 in order tosupply the needs of 130,000,000 people on the basis of the imperfect statistics and inadequate data of the past, becomes almost an impertinence. It is much more probable that the 400,000 square miles which now meet the needs of 75,000,000 people, with an enormous excess for export, will in 1930 still suffice for the domestic supply of 130,000,000 people, with a proportionate export corresponding to the present.
If the product of the farms of the West now yielding the largest crops, or of the renovated lands of the South now yielding the best crops, be taken as the average standard of the near future, as they should be, then it may be true in 1930, as it is now, that one fifth of the arable land of this country when put under the plow will still suffice for all existing demands, the remainder of our great domain extending the promise of future abundance and welfare to the yet greater numbers who will occupy the land a century hence.
I may add that in the course of a very friendly correspondence with Sir William Crookes, while we are still at variance in our estimates of the area which may be converted to the production of wheat in this country without trenching upon any other product, we are wholly at an agreement on a most material point. I quote from one of his letters: "Under the present wasteful method of cultivation there will be in a limited number of years an insufficient supply of wheat. Apply artificial fertilizers judiciously, and the supply may be increased indefinitely." I would only venture to add to the judgment of so eminent a writer the words "or natural," to the end that the paragraph should read, "Apply artificial or natural fertilizers judiciously, and the supply can be increased indefinitely."
Many years ago I was asked among others, "What would be the next great discovery of science or invention?" To which I replied, "A supply of nitrogen at low cost." Has not that discovery been made in the recent development of the functions of the bacteria which, living and dying upon the leguminous plants, dissociate the nitrogen of the atmosphere and convert it through the plant to the renovation of the soil? Is not the invention of methods of nitrifying the soil by distributing the germs of bacteria one of the most wonderful discoveries of science ever yet attained? Can any one yet measure the potential of any given area of land in any part of this country in the production of any one of its great crops? That there is a limit may be admitted. Can any one venture to say that any of our average crops yet approach beyond a small fractional measure the true limit of production, whatever it may be, either in cotton, maize, wheat, or any other product of the soil?
In this, as in many other developments of the theory of evolution, the factor of mental energy, which is the prime factor in all materialproduction, may have been or is almost wholly ignored. We are ceasing to treat the soil as a mine subject to exhaustion, but we have as yet made only a beginning in treating it as an instrument of production which will for a long period respond in its increasing product in exact ratio to the mental energy which is applied to the cultivation of the land.
By SPENCER TROTTER.
In southeastern Pennsylvania there comes a day in February that brings with it an indefinable sense of joyousness. A southerly wind wanders up the Delaware with a touch of the spring in its air that quickens, for the first time, the slumbering life. It is then that those mysterious forces in the cells of living things begin their subtle work—hidden in the dark, underground storehouses of plants and the sluggish tissues of animals buried in their winter sleep. On such a day the ground hog ventures from his burrow, some restless bee is lured from the hive to wander disconsolate over bare fields, a snake crawls from its hole to bask awhile in the sunshine, and one looks instinctively for the first breaking of the earth that tells of the early crocus and the peeping forth of daffodils. The southerly wind is more apt than not to be a telltale, for with all its springtime softness it is drawing toward some storm center, near or remote, that will inevitably follow with rough weather in its sweep. The country folk rightly call such a day a "weather breeder," and even the ground hog knows its portent in the very sign of his shadow. Come as it will, the day is really a day borrowed in advance from the spring, as though to hearten one through all the dreary days that will follow and, in starting the growing forces of vegetation, to make ready for the season's coming.
With this forerunner of the year come the harbingers of the bird migration. With the rise of the temperature to sixty or over, a well-marked bird wave from the south spreads over the Delaware Valley. On this balmy, springlike day we hear for the first time since November the croaking of grackles as a loose flock wings overhead or scatters among the tree tops. A few robins may show themselves, and the mellow piping of bluebirds lends its sweet influence to the charm of such a day. There is a sense of uncertain whereabouts in the bluebird's note, a sort of hazy, in-the-air feeling that suggests sky space. It does not seem to have the tangible element by which we can locate the bird as in the voices of the robin and the song sparrow. It is on such a day as this that song sparrows are first heard—cheeryditties from the weather-beaten fences and the bare, brown tangle of brier patches. The day may close lurid with the frayed streamers of lofty cirrus clouds streaking across the sky—the vaporous overflow of a coming storm—or a week of the same bright weather may continue with the wind all the while blowing softly out of the south, but sooner or later the inevitable winter storm must close this foretaste of the spring.
A decided wave of rising temperature usually reaches the Delaware Valley from the middle to the last of March, maintaining itself longer than the February rise, and ushering in a well-marked bird wave. It is about this time that the vanguard of the robin migration scatters over the country. The grackles or crow blackbirds, which have been more or less in evidence since their first appearance in February, begin renovating the old nests or laying the foundations of new ones in the tops of tall pines. The shrill call of the flicker sounds through the woods, and before the end of the month one is sure to hear the plaintive song of the field sparrow. This is about the time that the spicebush shows its yellow blossoms through the grays and browns of the spring underwoods, and the skunk cabbage unfolds its fresh, green leafage in rank abundance along the boggy course of woodland rills. A week earlier the streaked yellow and purple of its fleshy spathes shows here and there in the oozy ground by the side of the folded leaf spikes. It is just at this time, too, that one must go to the woods for the first spring wild flowers—bloodroot, hepatica, anemones, and the yellow dog-tooth violet—if one would get the real freshness of spring into his soul. The crows, that all through the winter filed away each evening in straggling lines of flight toward the distant roost, have broken ranks, and go rambling in small groups through the woods and over the fields of green winter wheat. Like the grackles, they have thoughts of courtship and the more earnest business of family cares. The liquid notes of meadow larks sound clear and sweet in the greening fields and pastures, and small flocks of vociferous killdeers scatter in wheeling flight over the newly plowed lands. In tangle covers the rustle of dead leaves here and there tells of the whereabouts of a flock of fox sparrows halting in their northward pilgrimage. The pewee is back, inspecting her last year's house under the span of some old bridge, and the melancholy voice of the dove is borne on the air from the fence rows and cedars along the farther side of fields.
After the 1st of April the tide of migration sets in with force, and the earlier waves bring several species of summer birds—those that come to build and breed in our woods—that rarely if ever make their appearance before this time. It is an interesting fact that none of the migrants that make their first appearance in April are everfound in the Delaware Valley during the winter, though several, if not all, of the species that come on the March waves are occasionally met with in the winter months. It appears, further, that the winter quarters of certain birds which are summer residents with us and some that are transient, passing on to more northern breeding grounds, lie not so very far to the south. If the last of March has been marked by warm weather lapping over into the first days of April, then one may expect soon to hear the familiar notes of the chipping sparrow from the swelling branches of garden shrubbery and the trees about the lawn, and a brown thrasher is sure to be heard volubly proclaiming his arrival from some near-by tree top. Among the budding sprigs of thickets the elusive chewink breaks into occasional fragments of song, and from the red-blossomed maples and the jungle of pussy willows and alders that fringe the meadow brook the metallic creaking notes of the red-winged blackbirds sound not unpleasingly. This jargon of the red-wing has a true vernal ring about it, suggesting the fresh green of oozy bogs and the loosening up of sap.
From the middle to the last of April there are several big waves of migration that bring many of the summer residents as well as some transient species, forerunning the greater waves that are to follow in May. On certain warm April days the barn and the bank swallows appear, and the chimney swifts are seen scurrying to and fro above the trees and house tops. These are genuine signs of the coming summer, for swallows and swifts feed only on the minute gnats and other ephemera that develop under conditions of warm temperature. Whoever knows of a martin box that year after year is visited by its colony has an unfailing source of delight at this time in watching the lovely birds. The martins are very prompt in their arrival, rarely coming before the 1st of April nor later than the 10th. We are aware for the first time that the house wren has come back by the voluble song that greets us some morning from the branches just beyond our window—a song that only the lover of his own rooftree can fully appreciate, for the wren's chant, more than any other bird song, seems to voice the home instinct in a man. By the last week of April the woods are fast closing up their vistas in a rich profusion of unfolding leafage. The umbrellalike leaves of the May apple are scattered everywhere through the woods and fields, forming conspicuous patches of green. During this last week of the month a few straggling thrushes make their appearance—the hermit thrush with its russet tail, the veery, and the wood thrush. The first two are transients, flitting through the underwoods or rustling among fallen leaves in search of their insect food. To hear the incomparable matins and vespers of the hermit one must follow to the bird's breeding range on the wooded slopes of the Appalachians or farther into the deep recessesof the Canadian forests. The wood thrush breeds with us, and the melody of its notes adds a peculiar charm to our groves and woodlands that would leave an unfilled blank in the choir if the bird were a transient like the hermit or the veery.
From the 1st to the 10th of May a succession of bird waves comes from the south of such vast proportions as to the number of individuals and variety of species that all the previous migratory waves seem insignificant in comparison. It is the flood tide of the migration, bringing with it the host of warblers, vireos, orioles, tanagers, and thrushes that suddenly make our woods almost tropical in the variety of richly colored species and strange bird notes. It would take a volume to describe the wood warblers, sylvan nymphs of such bizarre color patterns and dainty forms that one is fain to imagine himself in the heart of some wondrous forest of a far-away land. Their curious dry notes, each different in its kind and expression, yet all of the same insectlike quality; their quick, active motions, now twisting head downward around the branches, prying into every nook and cranny in their eager search for food, or fluttering about the clusters of leaves, add to the strange effect. Their names, too, are richly stimulative to the color sense—the black-throated green, the black-throated blue, the chestnut-sided, the bay-breasted, the black and yellow, the cerulean, the Blackburnian, the blue-winged yellow, the golden-winged, the blue-yellow-backed or parula warbler, and the Maryland yellow-throat are each suggestive of a wealth of coloring. Others have names that carry us to southern realms, like the myrtle and the palm warblers; and others again tell of curious habits, as the worm-eating warbler, the hooded fly-catching warbler, and the black and white creeping warbler that scrambles about the tree trunks like a true creeper. There is nothing in all the year quite like the May woods. Then, if never again, you can step from your dooryard into an enchanted forest. The light yellowish effects of new green in the feathery masses of the oak catkins and the fresh, unfolding leafage of the forest trees are a rich feast to the eyes. Against this wealth of green the dogwood spreads its snow-white masses of bloom. In sunlit spaces of greenness the scarlet flash of a tanager, the rich blue coloring of the indigo bird, newly arrived from its winter quarters in South America, and the glimpse of a rose-breasted grosbeak among the high tree tops are strangely suggestive of a tropical forest. The ear, too, is charmed with a multitude of curious notes. The weird cries of the great-crested flycatcher among the topmost branches, and the loud chant of the ovenbird with its rising cadence coming from farther depths of the wood are two of the most characteristic bird voices of the May woodlands. If one would have the famous song of the mocking bird in this sylvancarnival he has only to loiter in the nearest grove to hear the wonderful performance of the catbird. The catbird is the real harbinger of summer. He is familiar throughout the countryside, liked or disliked according to the dispositions of folks, but when he appears amid the May-day throng every one knows that summer has come. As a countryman once said to me: "You can't place any dependence on the robin—it may snow the very day he comes; but a catbird never makes a mistake—it's summer with him for sure."
The passing on of the great warbler waves to the north and the ending of the migration likewise mean the passing of the spring. It is summer any time after the 15th of May, or, to be more accurate, after the last of the migratory warblers, thrushes, and tanagers have passed beyond our woods. To a New-Englander summer will come a little later, nearer the true almanac date of June 1st. To a dweller in Virginia the last of April is the passing of spring and the advent of summer.
Some ten or more years ago several enthusiastic ornithologists living in the neighborhood of Philadelphia began keeping records of the times of arrival of the different species of birds, and at the same time noted the conditions of temperature in relation to the abundance of individuals. After several years of these observations they were able to see clearly that these bird waves were directly related to the waves of rising temperature marking the advent of warm spells of weather. One of the most significant facts deduced from these observations was the remarkable regularity in the first appearance of certain species. For example, the Baltimore oriole in eight years of observation never arrived before the 1st of May, and only twice later than the 4th—viz., once on the fifth and once on the 7th. The list on the opposite page shows the date of first arrivals extending over a period of eight years, from 1885 to 1892.[10]
1885.1886.1887.1888.1889.1890.1891.1892.FlickerApril 10Mar. 24Mar. 26Mar. 30Mar. 28Mar. 26Mar. 30April 2Chimney swiftApril 22April 23April 22April 20April 15April 22April 16April 27HummingbirdApril 29May 12May 12May 14.......May 7May 11.......KingbirdMay 6May 11May 7May 6May 6May 14May 1May 4Crested flycatcherMay 2May 12May 3May 1May 8May 1April 30May 3PeweeApril 3Mar. 20Mar. 21Mar. 22Mar. 27Mar. 27Mar. 31April 3Wood peweeMay 6May 15April 30May 13May 12May 14May 6May 17Red-winged blackbirdMar. 4Feb. 19Feb. 19Feb. 21Mar. 13Mar. 12Feb. 25Mar. 9Meadow lark.......Feb. 10Mar. 19Mar. 21Mar. 14Mar. 12Feb. 23Mar. 17Baltimore orioleMay 5May 4May 2May 2May 7May 1May 1May 3Purple grackleMar. 16Mar. 7Feb. 19Feb. 21Mar. 2Feb. 13Feb. 18Mar. 6Chipping sparrowApril 8April 9April 8Mar. 31Mar. 29April 8April 13April 4Field sparrowApril 11April 7April 9April 2Mar. 29Mar. 13Mar. 15Mar. 26ChewinkApril 22April 23April 27April 18April 11May 1April 18April 24Indigo birdMay 16May 11May 7May 12May 12May 10May 8May 10Scarlet tanagerMay 9May 12May 5May 8May 9May 4April 28May 3Barn swallowApril 22April 19April 21April 12April 22April 19April 19April 24Red-eyed vireoMay 7May 11May 4April 29May 5April 30May 2May 3Black-and-white warblerApril 30May 4April 27April 21April 20April 30April 24May 1Yellow warblerMay 6May 4May 2May 5May 11May 1May 8May 4Myrtle warblerMay 2April 10May 2April 25April 20April 27April 18April 7Black-throated green warblerMay 2May 11May 5April 26May 5May 2April 19April 30OvenbirdApril 30May 3April 29April 30May 3May 3April 29April 30Maryland yellow-throatApril 29April 24April 28April 30May 6April 30May 1May 3ChatMay 2May 12May 5May 5May 11May 5May 1May 3RedstartMay 2May 4May 3May 1May 4May 3April 29April 30CatbirdMay 2May 4May 3May 5May 5May 5May 4April 30Brown thrasherApril 24April 25April 28April 15April 22April 30April 19April 30House wrenMay 3April 27April 24April 28April 14April 30April 19May 5Wood thrushMay 2May 1May 1May 1May 3April 30April 23May 2Veery.......May 11April 25May 3May 6May 2April 28May 4Hermit thrushApril 13April 7April 9April 3April 10April 13April 12April 3RobinMar. 7Mar. 10Feb. 28Feb. 19Mar. 7Feb. 26Feb. 24Mar. 9BluebirdMar. 18.......Feb. 17Feb. 21Mar. 8Feb. 23Feb. 17Mar. 9
Another fact of great interest which bears on the south-to-north movement of migrating birds, and which these observations very clearly brought out, was the earlier appearance of individuals of various species at points nearer the river, the first arrival of the same species at points back from the river being, in many instances, several days later. The first report of the arrival of a given species usually came from a low, marshy tract of land immediately bordering the western shore of the Delaware. The second report came from a locality several miles back of the eastern shore of the river, but situated in the low plain of the river valley and within tide-water limits. The third report came from a place some miles back from the river on the uplands, but near the head of a stream emptying into theDelaware from the west. The last two places to report arrivals were situated farther up the river and some distance back from it. All this confirms the general idea that in migrating most, if not all, of the various land birds follow river valleys and invade the upland districts, lying back from either side, by way of the smaller tributaries.
The fact of greatest importance resulting from these observations was that relating to temperature. It was found that there was always a marked increase in the number of individuals of a given species following a warm wave of temperature as marked by a decided rise of the thermometer. The following graphic representation, based on the abundance from day to day of three common and easily observed species—the brown thrasher, chipping sparrow, and flicker—affords an interesting illustration of the relative movements of the two waves. It will be understood that the numbers in the extreme left-hand column refer to the relative abundance of individuals of the threespecies collectively. The inside column refers to temperature. The period of observation was twenty days, as shown by the line across the top of the figure.[11]