Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. BULLETIN No. 396 Contribution from the Bureau of Biologiéal Survey. x HENRY W. HENSHAW, Chief. SSS, f QS Pi fs : fe Yer —_ Washington, D. C. iy FR “2 \October 23, 1916 Nii e prt » of IL # ell a ei 2) P4 & SECOND ANNUAL REPORT OF BIRD“COUNTS IN THE UNITED STATES, WITH DISCUSSIQN/OF RE- SULTS. By WELLS W. Cooke, Assistant Biologist2 CONTENTS. Page. Page. Imitroductiony= 2 ses SoS eS 1 | Some notable reports____-______--_-_ 13 Plans for the 1915 counts_______-- 4 | Variations in bird life from year to Results in the Northeastern States__ 4 SS Er I Sl acl 12 A 9a Sa I a 15 Results in other sections__________ 7 | The possibilities from bird protec- The number of birds can be _ in- A 0 Wg te Ee a oa a7 CredSed ae tees aR be CRE PERS i SUMMA Y See See ee 20 The Berwyn, Pa., bird count_____-_ oe INTRODUCTION. A preliminary enumeration of the birds on many farms of the United States, made during the summer of 1914, was so satisfactory and the information obtained so important that it was decided to repeat the work in 1915. In the second effort it was planned to cover as many different kinds of country as possible and particu- larly to secure more records and more reliable data concerning birds in the Gulf States and in the region from the Plains westward. The returns from the 1915 bird count were on the whole very satis- factory. As in 1914, the largest number of reports from any single section came from the Northeastern States—that is, the States north of North Carolina and east of Kansas—but they are particularly gratifying because of their close agreement with returns of 1914 from the same section. When an enumeration of birds was first suggested the project was the subject of much good-natured banter and some criticism from those who declared the scheme utterly visionary. 1 Shortly after writing this report, and following a very brief illness, Professor Cooke died, March 30, 1916. He was a prominent ornithologist and the foremost American authority on the migration of birds.—EDITOoR. Notre.—This second report on the number and relative abundance of wild birds (see Dept. Bull. 187, issued Feb. 11, 1915) is for the information of workers and others inter- ested in the protection and increase of birds. 47849°—Bull. 396—i6 1 2 BULLETIN 396, U. S. DEPARTMENT OF AGRICULTURE. The reports of 1914 from farms of the Northeastern States agreed so well among themselves and with results obtained by other persons in previous years that they seemed to warrant the belief that their average closely approximated the actual facts. The counts of 1915 from the same region serve to strengthen this belief and to make it practically certain that the conclusions drawn as to the number of birds on these farms is very nearly accurate. A word of explanation may be offered as to just what results were expected from the work, and also as to what phases of the bird popu- lation question are not covered by these first two years of bird counting. The most important factor of bird life concerns its relation to human beings and has to do with its influence for good in helping the farmer destroy the foes of his crops. Hence to ascertain the numbers of birds in the trees and shrubbery on the acres actually devoted to crops and immediately contiguous thereto is more im- portant economically than on other lands, and these numbers have been most in mind in the work thus far conducted. The principal question of these two years has been, therefore, What kinds of birds and how many pairs of each kind nest on the farms in the area surveyed and remain on or near them during the middle of the summer, when crops grow fastest and also suffer most from insect enemles ? So far as the farms of the Northeastern States are concerned, the average of the 1914 counts was about one pair of birds to the acre, and as this number is so nearly the same as presented by the addi- tional work of 1915, it may be said with reasonable assurance that this is the average bird population of that part of the Northeastern States actually devoted to agriculture. The work has not yet reached the stage where the general average found—in the Northeastern States of nearly 800 pairs of birds to the square mile—may be subdivided and an estimate made of the num- ber of pairs of each kind. For some of the commonest and most widely distributed species, like the robin and English sparrow, how- ever, the reports are probably sufficiently numerous te permit an approximate estimate. The different kinds of birds on a farm are so much more variable than the average number of birds per acre that it will require many more counts to serve as reliable bases for formulating averages of species. ‘Two contiguous farms of 100 acres each may each support 100 pairs of nesting birds, yet the kinds of birds on the two farms may vary widely, according as one farm is upland, and the other lowland; one devoted to grain raising, and the other, in perma- nent pastures, to dairying; one supporting a growth of hardwood trees, the other showing nothing but evergreens. SECOND ANNUAL REPORT OF BIRD COUNTS IN THE U. S. 3 Many phases of bird population have scarcely been touched by the two years’ work. How many birds to the acre inhabit permanent marshes? What effect on the number of birds has the presence of a stream, a river, a pond, or a lake? What is the average effect of alti- tude or latitude on bird life? These and many other questions are interesting and important, but may not yet be answered. Another important question concerning bird population, which is partially covered by the counts of 1914 and 1915, relates to the num- bers of birds inhabiting those areas near large centers of human population which are not devoted strictly to agricultural purposes, as city lots, parks, cemeteries, etc. It is, of course, desirable to have the greatest possible numbers of native birds in all such places, and some of the returns show in a very striking manner how ‘quickly and abundantly the birds respond to efforts to make these sections better adapted to a large bird population. A brief explanation should be made regarding the qualifications needful in an observer to result in a satisfactory enumeration. The Biological Survey has for many years had several hundred mi- gration observers throughout the country reporting bird arrivals and departures. If a person is familiar with only half a dozen of the commonest birds and is well situated to note the earliest arrivals among these species, his notes on the birds he knows are just as valuable, so far as they go, as these of one who has a wider bird ac- quaintance. But in counting birds such partial knowledge is worse than useless. Ifa bird count is to have value, it must be true not only as far as it goes, but it must tell the whole truth. This requires that the enumerator be able to identify with certainty all the birds nesting on the area he covers, or be able to give a recognizable description of those he is unable to name. Lack of such knowledge has made un- usable some reports which were undoubtedly correct as to the species listed, but which showed their incompleteness by absence of records for the smaller and less conspicuous birds. Letters of criticism of the method used for counting the pairs of birds have been received. Of course if one is living on the area on which he reports and has the time and inclination to go over the ground repeatedly, day after day, until each nest has been actually located, his report would be more accurate and valuable than one made by ear by the method outlined in the circular of instructions. But this would require twenty to fifty times as many hours’ observa- tion, and hardly more than one person in a hundred would feel in- clined or be able to devote so much additional time to the work. Some six years of such work done by the writer convinced him that a person who knows the birds by their songs can use the method advocated and obtain, with the expenditure of a minimum of time and effort, a count that will compare favorably in accuracy with the most pains- 4 BULLETIN 396, U. S. DEPARTMENT OF AGRICULTURE. taking and exhaustive hunting out of the nests themselves. During two different years, in less than three hours of one morning, he made a survey of a 50-acre field which was supporting a bird population of some 30 species and about 75 pairs, and obtained results so nearly correct that continued observation on the field for the remainder of the season made scarcely any change in the figures thus obtained. PLANS FOR THE 1915 COUNTS. As the returns from the 1914 counts had shown that the method pursued gave satisfactory results, the same method was employed in 1915. A circular of detailed instructions was sent to each person who offered to help in the work. This was widely distributed; calls for additional bird enumerators also were inserted in the principal > fe fe eo @ee @enc. eer seonne de ee a © -22n20e0 cap t e Ly --4 miss. ALA. 4 GA- H e. i es . ---" 5 6 2140-92 Fic. 1.—Places from which bird-count reports were receivevd in 1915. ornithological journals; and in various other ways the matter was brought to the attention of those interested in birds. As a result about 315 reports, from every State in the Union, except Utah and Nevada, were received in 1915. As shown by the accompanying map (fig. 1), these are fairly well scattered over the country, but the largest proportion comes from the northeastern part of the United States, as was the case in 1914. RESULTS IN THE NORTHEASTERN STATES. The bulletin publishing the results of the bird enumeration of 19141 discussed at some length the work on farms of the North- eastern States. The most interesting phase of the 1915 returns is a consideration of the two counts from the same section to see whether the agreement is close enough to indicate accuracy in the 1914 con- clusions. 7 1 Bull. 187, U. S. Dept. Agr., Feb. 11, 1915. SECOND ANNUAL REPORT OF BIRD COUNTS IN THE U. S. 5 The number of new reports received from this section in 1915 was almost exactly the same as the total number received in 1914. This new material has been treated with reference to the same points con- sidered in 1914, and the comparison of the results of the two years is given in the subjoined table. The average farm in the Northeastern States, according to the 1910 census, contains 108 acres, and a farm of this size was used as the basis of the calculations for each year. TABLE I.—Results of counts in northeastern United States. Average 1914 1915 for 2 years. Acres. | Acres. | Acres. Average area covered by each count......-.-.-.-.- 2-22. eee e eee e eee eee ee --- 58 64 61 PLOW OCU AT Gs Pee co Rata ae ite ec te SES SNe ete eg nA oe 17 21 19 TEU NAA Le see a ck i ae lk Gea a ea ee at ener eae a ye 8 6 7 OT CHAT ee eee oe ne MCR era aa OOo USS Oe 2 4 5 5 NYO WE 0 LS a es ec Sie eae ta ES EA At nl nn Sear a es 3 9 6 analarouma eb wil diggs eee ead ea ee a EE VE ea ee es es oe 3 3 3 IBerimanen ane Ow ee eee eta see ee Oa ma LCs cea, te Maria dots 8 6 7 Pasturevlam dea oe ase aaa cee SE URN SORE ee A ANG SE ON 15 14 14 Pairs. | Pairs Pairs Average bird population on each area covered...........--.-.---.------00---- | 69 80 75 Average bird population for each 100 acres of the area covered.......---.-.---- | 119 125 122 Average bird population on each 100 acres of isolated woodland.........------ 175 199 187 Acres. | Acres Acres Average area not covered by the count in each farm.......--.-..-.-..-------- | 0 4 Blo Wwed larder set eer eee ae ee neh ean eae abt 15 13 14 18 RW ABO Wes CSAS Sors SSIES SEE SUS as REL eine rele AO Ri ae a aa 7 6 6 IWiGOGTAN Gis ae eee Lice aiictae se apes abate iat aie here lae cs coca ae tek cheba 18 16 17 Meadowaandspastunes isso as oes eee ais tal Ny een ee UE a oo 10 9 10 Pairs. | Pairs Pairs Probable average bird population in the woodland....................-------- 31 32 Probable bird population on the remainder of the area................----.--- 14 12 13 Probable bird population on each 108-acre farm (estimated from average of count area and area not Covered).......-..---- 2-2 eee ee ee eee eee e ee ee ee eee 114 124 119 The results of the counts of 1915 agree so very closely with those of 1914 as to indicate the strong probability that each represents on the average a close approximation to the truth. Some 25 persons who sent in reports of bird counts in 1914, taken on farms in the Northeastern States, made reports the next year of counts taken on the same areas. The average of these for 1914 is 117 pairs of native birds to each 100 acres o: farm land, while the average for 1915 is 122 pairs. Combining all the 1915 counts from farms in the Northeastern States with those of 1914 which were not repeated in 1915—that is, combining the counts of all the different farms received in the two years—gives the following results, expressed in the same terms as those used in the report of the 1914 enumeration: The average enumeration area on farms in the Northeastern States is 61 acres, 1. e., it consists on the average of the farm build- ings and the grounds surrounding them together with approximately 6 BULLETIN 396, U. S. DEPARTMENT OF AGRICULTURE. half the land of the farm, leaving an average of 47 acres of land farthest from the buildings not covered by the count. Thus two problems are presented: First, how the 61 acres covered by the census compare with the average farm; and, second, how the re- maining 47 acres compare in bird population with the 61 acres chosen. ) That portion of the average farm covered by the enumerations contained 32 per cent of plowed ground and 10 per cent of hay land, which, according to the 1910 census, is nearly the average percentage for the farms in this section of the United States. There is, however, a great difference in the relative sizes of orchards; these farms con- tained 7.3 per cent of orchard, whereas the average for the North- eastern States is only 1.2 per cent, or, in other words, the area se- lected for the bird enumeration contained six times as many acres of orchard as the average. Each area also contained the farm build- ings with accompanying shade trees, ornamental shrubs, small fruits, and vegetable gardens, forming the most favorable nesting sites on the farm and affording the largest quantity of food per acre. There is no doubt that the average 5 acres immediately surrounding the farm buildings contain more birds’ nests than any other 5 cul- tivated acres on the farm. As the farms selected contained orchards larger than the average and as orchards are especially preferred for nesting sites by many kinds of birds, the areas selected evidently have a bird population denser than that of farm lands as a whole. During each of the years 1914 and 1915, counts were made on isolated areas of woodland, and the average of all reports in the two years gives a bird population of 187 pairs to each 100 acres, while the farm land supported 122 pairs per 100 acres. It is evi- dent, then, that comparatively small areas of woodland contiguous to cleared and cultivated land offer better attractions as nesting sites than land which is wholly under cultivation, and contain a cor- respondingly larger number of birds’ nests. The 47 acres not covered by the two-year counts on each of these farms consisted on the average of 14 acres of plowed ground, 6 acres of hay land, 17 acres of woodland, and 10 acres of meadow and pasture. If the 17 acres of woodland contain on the average, as they probably do, 32 pairs of birds, the other 30 acres would have to support a bird population of 26 pairs to give these 47 acres the same bird population per acre as the part of the farm where the buildings are situated. It is not probable that the 30 acres would have 26 pairs, but they may easily have half that number, which, added to the population of the woodland and of the enumeration area, would make a total of 119 pairs on 108 acres, practically an average of 1 pair to the acre for the land in farms in the North- eastern States. SECOND ANNUAL REPORT OF BIRD COUNTS IN THE U.S. il RESULTS IN OTHER SECTIONS. In the report on the 1914 bird count it was stated concerning the data received that year from the whole of the United States outside the nertheastern section— Less than a dozen reports came from the South Atlantic and Gulf States, and the number is no larger from the States west of the Rocky Mountains; while the reports from the Plains States—North Dakota to Oklahoma—are too few to be used as representing average conditions in this region. These three divisions, the South, the West, and the Plains, are so diversified in climate and agricultural conditions and vary so widely in their bird life that many more bird censuses must be available before generalizations can be made for the whole country and reliable conclusions drawn. The reports received in 1915 from the South, the West, and the Plains, instead of yielding a satisfactory bird return from these districts, serve rather to accentuate the difficulties of the problem. Deductions from a few of these, following, will show the wide vari- ations and indicate the complexity of bird life in these parts of the United States. COUNTS IN THE PLAINS REGION. Of a number of reports received from the Plains region from Oklahoma to North Dakota, only those were selected which seemed to have resulted from counts made under about average conditions. These covered an average area of 56 acres, divided into 15 acres of plowed land, 5 acres of hay land, 1 acre of orchard, 3 acres of wood- land, the farm home with the other buildings and farm garden, and the remainder, 29 acres, divided into about one-fourth meadow and three-fourths pasture. The percentage is a little smaller than the average for these States in plowed land and hay land, about the average in meadow and pasture, and considerably above it in wood- land and orchard. As these last two are the largest factors in the size of the bird population, it follows that these enumeration areas probably have a larger bird population per acre than the average for the States as a whole. The average of these reports shows 70 pairs of nesting birds of 22 species on the 56 acres, or at the rate of 125 pairs to the 100 acres, precisely the same as for farms in the Northeastern States, which contained the farm home and exceptionally favorable con- ditions for a large bird population. But while these figures are probably entirely correct for the part of the farm which contains the buildings, it is not possible to estimate from any data yet received the bird population on the remainder of the farm outside the,enumeration area. The farms in the Plains region are large, averaging 297 acres each, as compared with only 108 acres in the Northeastern States. The part of the average Plains farm not covered by the bird count consists of 241 acres, 8 BULLETIN 396, U. S. DEPARTMENT OF AGRICULTURE. divided into 92 acres of plowed land, 27 acres of hay land, 3 acres of woodland, 34 acres of improved meadow and pasture land, and the remainder, 85 acres, of wild, treeless, native prairie. The average bird life per acre on such land is naturally much less than on the part of the farm selected for the enumeration. How much less, the data in hand are not sufficient to determine. Anyone who has ridden over the native prairie knows how seldom birds are seen, and an at- tempt was made at Sisseton, S. Dak., to obtain a numerical state- ment of this scarcity. Ona tract of 40 acres of prairie pasture land adjoining the Sisseton town site, but having better than average con- ditions, in that a stream of water, bordered with brush, crossed the tract, the following were found nesting: Killdeer, 2 pairs; prairie horned lark, 3; Sennett nighthawk, 2; lark bunting, 2; and meadow- lark, 3; a total of 12 pairs on 40 acres, or at the rate of 30 pairs to 100 ‘acres, aS compared with the 125 pairs to 100 acres of the farm land. Some suggestive figures in this connection come from Onaga, Kans., where a tract of 80 acres of native pasture, crossed by a creek with a narrow fringe of native timber and occupied at one end by a small cornfield, supported a population of 31 pairs of native birds of 22 species, or in the proportion of about 40 pairs to 100 acres. The ad- joining 40 acres, containing the farm home, a 5-acre orchard, and 6 acres of groves, was the summer home of the same number of kinds of birds represented by 49 pairs, or at the rate of 122 pairs to 100 acres. REPORTS FROM THE ROCKY MOUNTAIN STATES. The foregoing records from the Plains region are from the part east of the one hundredth meridian, where the average annuai rain- fall is more than 20 inches and where crops are raised successfully without irrigation. To the west, as the rainfall diminishes, the native bird population on the open prairie decreases until in some of the more desolate sections it almost disappears. A little west of the one hundredth meridian, near Hobbs, N. Mex., in the extreme southeastern corner of the State, one tract of 80 acres, all native pasture except a 20-acre field of milo maize, had a bird population of 22 pairs representing 9 species; a neighboring 80 acres, with only 10 acres in milo maize, showed 17 pairs of 8 species; while in the same township still a third 80 acres, none of which had ever been disturbed by the plow, was supporting only 13 pairs of 5 species, notwithstanding each of these equal areas con- tained a set of farm buildings with windmill and tank. The average of these three counts is 17 pairs to 80 acres, or 21 pairs to each 100 acres. Still farther west, in the irrigated district of western Colorado, two reports have been contributed showing the effect of irrigation on the density of bird life. The first area consisted of 320 acres of irrigated SECOND ANNUAL REPORT OF BIRD COUNTS IN THE U.S. 9 orchard, near Grand Junction, the trees from 3 to 6 years old; the area was interspersed with small fields of alfalfa, grain, and root crops, and contained about ten sets of farm buildings, sheds, and yards for live steck. The native birds were represented by 116 pairs of 17 species (in addition to a colony of 65 pairs of violet-green swallows, most of which had come within the last few years), 5 pairs of English sparrows, and 12 pairs of the introduced California quail; a total of 198 pairs of birds on the 320 acres. Just above this irrigated land lay a tract of 320 acres in its original wild state, of low hills and small gullies; the hills sparsely covered with sage, saltwort, and other desert plants, and the gullies lined with bushes. Its bird life consisted of the following pairs: Burrowing owl, 3; Arkansas kingbird, 1; Say phoebe, 1; desert horned lark, 5; western lark sparrow, 2; white-rumped shrike, 2; and rock wren, 3; a total of 17 pairs of 7 species. The irrigated land supported a bird popu- lation at the rate of 66 pairs to 100 acres, while on the contiguous -nonirrigated land the bird hfe shrank to 5 pairs to 100 acres. A 40-acre tract on the outskirts of Tombstone, Ariz., containing in one corner a few houses with their yards, but for the most part covered with a sparse growth of desert shrubs, “ not heavy anywhere, but quite general,” and with no surface water, had a bird population of 50 pairs of 26 species, of which only 4 species were seed-eaters and the rest insectivorous. At a little distance from the town a 40-acre tract of “semidesert” covered with a rather heavy growth ot brush, mostly less than 6 feet high, showed 31 pairs of 16 species. No enumeration has yet been made on the real desert. In the mountains of Arizona, near Flagstaff, a tract of 70 acres at about 7,100 feet elevation, covered with western yellow pine and Gambel oak, supported a bird population of 81 pairs of 18 species. A public park in Missoula, Mont., with exceptionally favorable conditions for bird life, showed 59 pairs of 20 species on 40 acres. Along the shore of Flathead Lake, Mont., 45 acres of woodland had 67 pairs of 24 species. A tract of 48 acres near Missoula, Mont., with 64 acres in orchard and the rest in native prairie, furnished a home in the orchard for 16 pairs of birds, while only 4 pairs could be dis- covered on the 40 acres of shrubless prairie. These examples make it plain that there is a much smaller bird | population per acre west of the one hundredth meridian than in the Northeastern States. Just how much smaller can not be estimated from the reports so far received. Probably no State in the Union has greater variations in bird life than California. A few examples will show some of these, though it will require many more bird counts than those so far made to furnish an adequate basis for estimates of averages. A plot of 20 acres of the campus of the University of California, with conditions 47849°—Bull. 396—16—-2 10 BULLETIN 396, U. S. DEPARTMENT OF AGRICULTURE. for birds much more favorable than average, showed 87 pairs of 23 species of native birds. A 60-acre tract of wooded hillsides near Gilroy, Cal., was supporting 36 pairs of 10 species. This is close to what would be expected in the Eastern States under similar conditions. | There is no place on the farm where the help of birds is more needed than in the orchard, and the following counts show how the birds congregate where food, shelter, and building sites are closely associated. The numbers of nesting pairs in a tract near Gilroy, Cal., containing an orchard of 30 acres of apricots, prunes, peaches, and grapes, and about 8 acres of pasture and creek bottom, the farm home and other buildings, and many large native trees, are as fol- lows: Oregon towhee, 4; California towhee, 12; valley quail. 5; nll- deer, 1; green heron, 3; California woodpecker, 3; red-shafted flicker, 7; western bluebird, 8; western meadowlark, 1; Bullock oriole, 2; Arkansas kingbird, 2; Traill flycatcher, 4; black phoebe, 6; Law- rence goldfinch, 15; lazuli bunting, 1; barn owl, 3; dotted canyon wren, 2; western winter wren, 7; long-tailed chat, 1; California shrike, 2; tree swallow, 5; cliff swallow, 12; California jay, 4: Allen hummingbird, 6; western blue grosbeak, 1; black-headed grosbeak, S; house finch, 18; western mourning dove, 6; western chipping spar- row, 10; Pacific nighthawk, 2; russet-backed thrush, 2; western lark sparrow, 7; green-backed goldfinch, 2; and English sparrow, 4; a total of 176 pairs of 34 species on 38 acres. A similarly dense, though less varied, bird population in a 52-acre peach orchard is shown by a count made near Port Clinton, Ohio. This showed 108 pairs of common farm birds, a colony of 36 pairs of purple martins, and 6 pairs of English sparrows, or a total of 150 pairs of 29 species. ESTIMATED BIRD POPULATION OF THE SOUTHERN STATES. Bird counts made in Florida show an average of 77 pairs of native birds of 20 species and 5 pairs of English sparrows on 83 acres. The enumeration areas average 4 per cent of plowed land, 21 per cent of woodland, and the remainder open meadow or pasture land. The average of the farms of the State 1s 12 per cent of plowed land and 60 per cent of woodland, so that the proportion in the enumer- ation areas does not at all represent average conditions in that State, and the counts can not be used in estimating the average bird life of the State. Reports from Louisiana show an average of 95 pairs of birds of 29 species on 53 acres, of which 39 per cent is plowed land, 18 per cent woodland, and 41 per cent pasture, while the average farm of the State contains 87 acres, of which 28 per cent is plowed land, 41 per cent woodland, and 28 per cent pasture. SECOND ANNUAL REPORT OF BIRD COUNTS IN THE U.S. 1a The enumerations from Texas average 91 pairs of birds of 21 species on 60 acres, composed of 43 per cent plowed land, 17 per cent woodland, and 40 per cent pasture; while the average farm of the State contains 270 acres, divided into 15 per cent plowed land, 25 per cent woodland, and 60 per cent pasture. The average of all counts received from the Southern States, North Carolina, Arkansas, and Oklahoma to Florida and Texas, is 76 pairs of birds of 23 species on a farm of 58 acres, which consists of 83 per cent plowed land, 2 per cent hay land, 24 per cent wood- land, and 41 per cent meadow and pasture land. The average farm for this section contains 120 acres, divided into 24 per cent plowed land, 2 per cent hay land, 35 per cent woodland, and 39 per cent meadow and pasture. The enumeration areas thus differ too radi- cally from the average farm conditions to allow safe generalizations, and yet it is worthy of notice that the average for the census areas in this southern section is 131 pairs of nesting birds to 100 acres, while for the Northeastern States the corresponding figure is 125 pairs, and for the Plains region 125 pairs. There is probably more than a mere coincidence in the close agreement of these figures, and they seem to indicate that on the average the farmhouse area and the approximately 60 acres surrounding it support about the same brrd population—76 pairs of nesting birds—in all the States east of the one hundredth meridian. There is still left unsolved the problem of the bird population on the areas in the South and in the Plains region which are not in- cluded in the reports. These areas in the Northeastern States con- stituted only 41 per cent of the total land of the farms, while in the South they form 52 per cent of the whole, and in the Plains region 81 per cent. From the 59 per cent of the land covered by the count it is possible in the Northeastern States to estimate with fair accuracy the birds on the 41 per cent not covered, but it is not at all safe to generalize in the South, with less than half the farm area repre- sented by the count, and still less so in the Plains region, where less than a fifth of the area is included. THE NUMBER OF BIRDS CAN BE INCREASED. The most important fact brought out by the 1914 count was that the average bird population on the farms of the United States can be largely increased by protection and furnishing food and shelter. The 1915 count presents several more instances of a nu- merous bird population following well-directed efforts for its in- crease. A farm of 65 acres near Westerville, Ohio, comprising plowed land 23 acres, hay land 22 acres, pasture 5 acres, orchard 5 acres, house and garden plot 2 acres, and swamp and wooded iy BULLETIN 396, U. S. DEPARTMENT OF AGRICULTURE. -creek borders 8 acres, showed a population of 110 pairs of native birds and 25 pairs of English sparrows, or about double the average for the State. A farm of 78 acres near Strasburg, Ohio, with about. the same proportion of the different fields, had 126 pairs of native birds and 8 pairs of English sparrows, also about double the average. A farm of 40 acres near Middletown, Conn., containing 10 acres of plowed land, 3 acres of woodland, 5 acres of pasture, 12 acres of orchard, and 20 acres of meadow, had a bird population of 165 pairs of native birds, 8 pairs of English sparrows, and 15 pairs of starlings; a total of 188 pairs, or more than four times the aver- age. A farm of 40 acres at New Hope, Pa., called “The Hedges,” from its numerous osage orange hedges, and divided into plowed land 15 acres, woodland 2 acres, orchard 5 acres, and grassland 18 acres, supported a bird population of 136 pairs of native birds, 17 of English sparrows, and 1 of the starling; a total of about four times the average. These examples are all of farms that are used for ordinary farm- ing purposes, and where no attempt has been made to attract an extra number of birds by winter feeding or by putting up nesting boxes. The large bird population is due solely to absolute protec- tion and to leaving abundant chances for favorable nesting sites. THE BERWYN, PA., BIRD COUNT. As noted in the report of the 1914 enumeration, the first published bird count in the United States was that made in 1901 at Berwyn, Pa., by Mr. Frank L. Burns. After a lapse of 13 years Mr. Burns in 1914 repeated the count on the same area, and the results have lately been published. His enumeration area consisted of 640 acres, divided approximately into 27 per cent woodland, 16 per cent gar- dens and shaded lawns, about 30 per cent plowed land, and the re- mainder, about 27 per cent, covering pasture land, drives, highways, and railroads. The tract is thus somewhat more favorable for birds than the average of the lands covered in 1914 and 1915 by the Bio- logical Survey reports. In his second count Mr. Burns found 617 pairs of native birds on the 640 acres as compared with 588 pairs in 1901, or an average of 97 pairs of native birds to 100 acres as com- pared with the 100 pairs estimated for 1914 by the Biological Survey for the farms of the Northeastern States. If English sparrows are included, however, Mr. Burns’s total is 112 pairs to 100 acres, as com- pared with the 105 pairs found by the Biological Survey in 1914. Mr. Burns finds 95 pairs of English sparrows on the 640 acres, or at the rate of 15 pairs to 100 acres, where the Biological Survey’s aver- age is 5 pairs. Mr. Burns finds 15 pairs of English sparrows to each =— ee 1 Burns, Frank L., Second Sectional Bird Census, 1914, Taken at Berwyn, Chester County, Pa. Bird-Lore, XVII, 109-111, March-April, 1915. SECOND ANNUAL REPORT OF BIRD COUNTS IN THE U. S. 13 _ 100 pairs of native birds, while the Biological Survey’s estimate is 5 pairs. Based on his count, Mr. Burns estimates 165,000,000 individ- ual English sparrows in the United States east of the Mississippi River, but this may be somewhat too high for the whole area, since the English sparrow is especially partial to human society and the square mile worked on by Mr. Burns contained more than one person to the acre, or a human population .thirty times as dense as the average for farm land in the United States east of the Mississippi River, and several times the average density for the whole land in- cluding cities. 7 SOME NOTABLE REPORTS. The most elaborate report to the Biological Survey in 1915 was that of the campus of Cornell University, at Ithaca, N. Y. Its 256 acres was divided into six blocks, and the survey of each was made by a different person, the whole being in charge of Prof. Arthur A. Allen, of the university. Following is a description of each of the six blocks: Block A, 22 acres, hillside pasture with a few trees; block B, 34 acres, hillside planted with scattered groups of trees and shade trees about residences, with very little shrubbery; block C, 87 acres. con- taining lawns, shade trees, a little shrubbery, and most of the uni- versity buildings; block D, 24 acres, about one-third woodland, con- taining residences with shade trees and some shrubbery; block E, 64 acres, a Clover field, a small nursery, a little woodland, and many new buildings; block F, 25 acres, a hillside pasture covered with a thicket of thorn apple and containing a stream. It is interesting to note the wide variations in the bird popula- tion of the various sections. Block C, which contains the university buildings and therefore has the largest human population, hundreds of students passing and repassing all day, has less than the average of native birds but swarms with English sparrows, in numbers al- most equal to the total of the native birds. Block D, containing ~ residences, with their shade trees and shrubbery, has the greatest density of native bird population—84 pairs on 24 acres; and blocks A and F, hillside pastures, though supporting a population of native birds considerably above the average for the State, are almost free from English sparrows. (See Table IT.) : Another count, representing great and painstaking work, was made by M. S. Crosby on Grasmere Farms, near Rhinebeck, N. Y. A 210-acre section containing 92 acres of woodland, 38 acres of plowed land, 25 acres of meadow, 40 acres of orchard, and 15 acres of lawns, drives, gardens, and buildings, was found to have a bird population of 54 different kinds represented by 366 pairs, or an average of 17¢ pairs of native birds to 100 acres, nearly the same as on the Cornell University campus. 14 BULLETIN 39%, U. S. DEPARTMENT OF AGRICULTURE. TasLe I1.—Number of nesting pairs on each of siz blocks of the Cornell Univer- sity campus. Blocks. Species. l ; Total. A. B Cc D. E F Sereech- Owl-c as i=. so eee ee eee eee gs5222222522 1B peeresd ereee | Met aee [seen 4 ppotted Sand piper: 2-2-2... sss ssescc on sce nssen ese ee l= ee eee Se ae ae 1 Kanpiisher ss. 0 04. 6 sitet Soe ees Bee. Co Seeee fe leaks €: Eppes) peeres as noe Bes 23 1 Harry woodpecker -252 252522522250 scone saies Se ee oe eee eee ieee eae peaee i ie ee eck Downy ;wood pecker: . 222-5 «2222-55-22 33-2. . sa eee jase )eeet 2 eee 1 1 i Ef 522 222-~252 22s oeee eee | 46 | 81) 193 99 75 79 573 A Gres per blocks? oo 222 cco. Sas ens ae oe oe eee eee | 22 34 87 24| 64 25 256 Nesting pairs oi native birds per 100 acres..........--...---.| 186 | 200; 122) 350 77 | 300 166 Nesting pairs of English sparrows per 100 acres.............. 14; 44! 100 62 7 4 fe ee: | 56 Total nesting pairs per 100 acres: .... -.. fos --S- c cc cb ope Ses 205 | 244 | 222} 412} 104 316 225 i | I In comparison with the above may be placed a report from Ran- toul, Ill., on a farm of 400 acres, of which 315 acres were in corn and oats, and of course practically destitute of birds’ nests, leaving only -85 acres to support the 88 pairs of native birds found on the place. Such farms are very common throughout the central corn belt, and while the 88 pairs are about the average for the 85 acres, the farm as a whole shows an average of only 22 pairs to the 100 acres. The count for 1914 showed an average of 6 pairs of robins and 5 pairs of English sparrows for each farm (of 108 acres) covered, The accuracy of these figures has been called in question by indi- viduals who felt sure that the English sparrow was by far the most FA OD A tO CO TD He OD DO A bo SECOND ANNUAL REPORT OF BIRD COUNTS IN THE UW. S. 15 abundant bird in the Northeastern States. The reports for 1915 in this part of the Union bear out the estimates for 1914 that the robin is the more numerous, since the averages are 8 pairs of robins and 6 pairs of English sparrows for each farm. The average of all reports for the two years shows 7 pairs of robins and 54 pairs of English sparrows for each farm covered. VARIATIONS IN BIRD LIFE FROM YEAR TO YEAR. A most interesting and instructive report has been received from Mrs. A. B. Morgan, of Woodstock, Vt., giving the results of enumera- tions for each of the last eight years on a tract near Woodstock. The tract contains 92 acres, 20 acres of which is woodland, the balance being devoted to permanent pasture and the usual crops of a Ver- mont farm. The conditions on the farm have scarcely changed dur- ing the eight years and the bird hfe has not much altered—84 pairs of birds in 1915 as compared with 87 pairs in 1908—but it is inter- esting to note the wide variation in both kinds and numbers of each registered in the annual counts. The total number of species nesting on the place in the eight years aggregates 49, while the highest number in any one year is 44 and the lowest 35, a range of from 90 per cent to 72 per cent of the total. The average number of nesting pairs per year is 82, with variations from 77 to 87, or an average variation of 3 per cent and a maximum variation of only 6 per cent. These variations have been attributed chiefly to the depredations of hawks. (See Table ITI.) A tract of 50 acres at Viresco, Va., came under the writer’s ob- servation in 1907. It consists of woodland, 21 acres; plowed land, 5 acres; permanent pasture, 15 acres; and the remainder, 9 acres, brushy land along a stream and on a hillside. At that date much of the land not in woods had lately ceased to be cultivated and was grow- ing up in brush, while the underbrush had just been thoroughly cleared out of all the woods. In the last eight years the underbrush has worked back into the woods, while a great increase has taken place in the brush and young trees along the stream and on some 3 acres that were formerly cultivated. During all the years bird | life has been rigorously protected, but there has been no extra bird feeding either winter or summer and no putting up of bird boxes, with the exception of a single small martin house; this, however, was scorned by the martins, which are on several neighboring farms, but was used fitfully by bluebirds, house wrens, and crested fly- catchers. A bird count was made by the writer in each of the last five years, and the results show a steady and pronounced gain in the number of kinds of birds nesting about the place, and a still greater gain in the i6 BULLETIN 396, U. S. DEPARTMENT OF AGRICULTURE. ~ total number of nesting pairs. Indeed, the gain in this latter respect, 69 per cent in the five years, is more than may be explained by the growth of bird food and shelter on the place and is probably due to the entire freedom from disturbance which the birds have come to recognize. Table IlIl.—KHinds of birds, and number of pairs of each, nesting each year from 1808 to 1915 on a tract of 92 acres near Woodstock, Vt. | Species. | 108 | 1909 1910 | 1911 | 1912 | 1913 | 1914 1915 Mims SD bet ID bet O9 WD 1D bet bt Hermit i ee a Rent Re | 2 4 i Black-capped ehickadee:__2=*=-2 52-5. ee 3 2 | y. te Os) Red ei ee ee ea See Fe, : Gee fs 352h et C2 A eee: Bee i 1 wo Black and white Warbler =< oi {iss 52 te = sath ee Welliwowarblen.2~ 25) oe ee eee bo Chesimmt-sided warbler... 325 -s- 2 ee Ly ae oi ne ee Sea OY ae te | Solitary warno so Se. 2 Seer: Se eS eee 3 mea j —— ‘ Black-throated green warbler. .............--..------ eee a= ps eek be ng Sparrow Rose-breasted grosbeak.........-.-----.------------- LECT ET 1111 311) ne er ey ee ee Ne LoS i ee | . ; bee Ee Baliimere orible-.2_ A212. oes Se ee | een peaees jet Pot beet CAD beet CAD beet fee feet bed bet INS) beet CD alt 09 o 3 t ' ‘ ’ ‘ ‘ ‘ ' ' ‘ ' ’ i ’ ’ ' fed fk font MT RD Ho a BD bat et at 9 1 Fat 9 ot Pt yee Creare crane crcy cerry. rer Maryland -yollow-throat: —-. | 222225202 cs Eee i Sg en 8 ss 2 eee see ees Pres some Least yeatcher ph ce See eo ee oneeee 8 ee we ee «1 CAD bet IND IND bt bt et J ' ’ ‘ fo pets H fet ett bet BD ide me 9 hte ont a CRC Noe Cone ho Ha GO GD CAD feet bk BD beet fed bet Chimney Swit: Stk 65s pelt es ag At ee | | | | a9] a: i= | +. ag be, :0 fu iy | | i) o ae ie de I egal fn edlnalon Poh BSD ISD BD CAD et CAD beet BND IND fret bre bet bt OMe DO bo ee ees Prk Pek beh bet BD bet I CAD beet CAD Peet em DAD) fet pd et Refied' erowuse: 2: . 2222 ot 3S. Ee eS Upland plover. 2220 5 oo oa scene ae tee one oes eee | bt et 5 Total number of different species Total pairs of nesting birds. .......-.........-.- R It is interesting to note the change in the character of the bird population from year to year. While 42 kinds of birds nested on the place in the course of the five years, the greatest number in any one year was only 34, while each year a dozen or more kinds of birds nested within sight of the 50 acres, but not within the enumeration area itself. (See Table IV.) haw Vuh» SECOND ANNUAL REPORT OF BIRD COUNTS IN THE U.S. Li TABLE I1V.—Kinds of birds, and the number of pairs of each, nesting on a 50- acre tract at Viresco, Va., during each of the five years, 1911 to 1915. Species. 1911 | 1912 | 1913 | 1914 | 1915 Species. 1911 | 1912} 1913} 1914 | 1915 Be DIG So: 55-2 ase neces |b ae PA Ser. 1 || Song sparrow.....-.---- 6 6 6 5 3 Southern robin........ MA eaede Goad eacad Cocee Field sparrow....-.-.-- 3 3 4 4 7 Wood:thrushe. 0-552 52|-- 5-2 1 1 2 2 || Chipping sparrow......]--.-- 1 1 1 1 Carolina chickadee.-....|....- 1 1 ae ee 1 |} Grasshopper sparrow.. 1 1 1s eee [ae Tufted titmouse..-..... 1 1 1 2 2 Orchardtonioles = o-— 22> | cee ser oleae US eaeee House wren.......--.-.- Pelee a2 2 1 1i||}-Am erican: Crowsoserice-| the rote cre 1 1 Carolina wren......-.-.- 1 a al aed ha as Dl LU Os aYenn sehr cit ea| Se esl eeae she ceeloeerr 1 Brown thrasher..-..--.-.|.....|--... WHE SSod looks Acadian flycatcher.....|....- 1 1 1 2 Cathirdte 2-22-85 2s 3 2 4 5 7 || Wood pewee.......-..- 2 1 2 3 2 Black and white war- PHeebe@rsa see ceiis= ce 2 1 1 1 3 15) (Se as ae is 1 1 2 2 3 || Crested flycatcher. ..... aaa 1 1 1 Parula warbler........-|--.-- WN Aes eee esese King binde seeseeeee ons seeee 1 1 ware Oven-bird........-.... 3 4 4 6 6 Ruby-throated hum- Marwan’ yellow-throat) 4 4 5 3 5 MINSDILG see sae soe os eels Isjaceaelles’ oc Ree eRe sols es lciajeds 2 2 1 3 2 Whip-poor vill. 70 1 IW eSesq) 72! 1 Hooded warbler......-- WN ladoee 1 1 2 || Downy woodpecker. . 1 1 leesac 1 Redstart.............-- 1 2 2 2 4 || Hairy woodpecker ..--..|-..-.]-..--|--.-- Willossos White-eyed vireo...... 1 1 3 3 2h Motrin eid OVC saa see | sare ce asicinic| meratelenicieei- 1 Yellow-throated vireo. 1 2 2 5 PVM e4o) SAGs Aes esecallecoorllsodaclacocsloodsn 1 Red-eyed vireo.......-.- 2 3 4 9 7 ———_——_|——_|——__|- — Rough-winged swallow. 1 1 1 1 1 Total number of Scarlet tanager........- 1 2 2 2 1 different species..| 27} 30] 32] 29 34 Indigo bunting.........| 3 3 1 3 3 é Cardinale ec secccer 1 2 2 2 2 Total pairs of nest- Towhee:o: 3.2.522s25-%- 2 1 2 2 1 ing DILGS:=-2-cee2 <= 48| 53] 63] 74 81 THE POSSIBILITIES FROM BIRD PROTECTION. To increase the number and variety of birds about the home, whether in the country or in the city, has become the laudable desire of an increasingly large number of persons. Among the reports are examples of such decided successes in these endeavors that a few in detail will be of interest. Two city blocks, 10 acres in all, in the town of Aiken, S. C., have for many years been liberally supplied with bird food and water. In the summer of 1915 the following nests were counted: Blue jay, 14; red-headed woodpecker, 11; mockingbird, 9; brown thrasher, 8; catbird, 7; cardinal, 6; wood thrush, 4; orchard oriole, 1; towhee, 1; English sparrow, 4; total, 10 species and 65 nesting pairs. This shows a large number of nesting birds comprising a comparatively small number of species, the blue jay and the red-headed woodpecker being the most numerous. At Olney, Il., Mr. Robert Ridgway has devoted 8 acres ae land to homes for oe His aim is to have the greatest possible variety, and of course as many individuals of each as is consistent with this, but a great number of different kinds is considered more important than mere numbers of individuals. Asa result of more than ordinarily favorable natural conditions, supplemented by the planting of differ- ent kinds of shrubbery for bird food and shelter, furnishing a super- abundance of nesting boxes, and supplying an unlimited quantity of food all the year and water through the summer, these 8 acres have become the summer home of 70 pairs of native birds of 31 species, as follows: Mourning dove, 13; screech owl, 2; yellow-billed cuckoo, 1; 18 BULLETIN 396, U. S. DEPARTMENT OF AGRICULTURE. red-headed woodpecker, 1; flicker, 2; chimney swift, 1; ruby-throated hummingbird, 1; kingbird, 1; crested flycatcher, 2; wood pewee, 2; alder flycatcher, 1; blue jay, 3; cowbird, 1; meadowlark, 1; orchard oriole, 2; Baltimore oriole, 1; bronzed grackle, 3; goldfinch, 1; chip- ping sparrow, 1; field sparrow, 1; towhee, 1; cardinal, 2; indigo bunting, 1; Maryland yellow-throat, 1; catbird, 3; brown thrasher, 3; house wren, 8; tufted titmouse, 1; Carolina chickadee, 1; southern robin, 7; bluebird, 1. Mr. Ridgway’s experience with some of these birds in their relations to their fellows may be stated in his own words. | The red-headed woodpecker, although one of our most strikingly handsome birds, and in many ways a most interesting one, is, unfortunately, extremely selfish and aggressive. Our single pair prevented any other woodpeckers (the downy, hairy, and red-bellied) from nesting in any of the boxes, drove two pairs of flickers and one pair of crested flycatchers from boxes which they had chosen, and even attacked the purple martins whenever they alighted on the box put up for them. * * * The house wren is equally tyrannical, and no other small bird can nest in his vicinity. Several pairs of Carolina chicka- dees and tufted titmice, and a pair of Bewick’s wrens that had been with us all winter, would have nested in boxes near the house but for the rascally house wrens, who, though possessing boxes of their own, drove the other birds away. His most interesting experiences, however, were with the blue jays and the grackles. The blue jays were very troublesome, de- stroying fully 90 per cent of the eggs in the first-buift nests and even killing and partly devouring half-grown young of the mourn- ing dove. It became necessary to “discourage” the blue jays and the grackles to the extent of 15 pairs of the former and some 50 pairs of the latter before the smaller birds had a fair chance for existence. Parenthetically it may be remarked that on the grounds of the Department of Agriculture at Washington, D. C., the grackles have been known to feed upon newly hatched English sparrows, while the young of the grackles, and to even a greater extent of the English sparrows, also, similarly suffer from attentions of fish crows. Quite different from Mr. Ridgway’s experience with house wrens is that of Mr. Gilbert H. Grosvenor, at his summer home, Wild Acres, in Maryland, a few miles from Washington, D. C. Here, as a result of several years’ endeavors, he has a colony of house wrens which in 1915 numbered 19 pairs, all in boxes put up for them in the immediate neighborhood of the house, and yet other birds also were numerous, and in the 5 acres surrounding the house there nested, in 1915, the following additional pairs: Flicker, 3; southern robin. 8; catbird, 3; bluebird, 3; orchard oriole, 2; yellow warbler, 1; brown thrasher, 1; chipping sparrow, 3; pheebe, 2; barn swallow, 1; indigo 1Ridgway, Robert, Bird-Life in Southern Illinois. Bird-Lore, XVII, 1-7, 91-103, Jyan.—April, 1915, SECOND ANNUAL REPORT OF BIRD COUNTS IN THE U. 5. 19 bunting, 1; grasshopper sparrow, 1; song sparrow, 2; meadowlark, 1; red-headed woodpecker, 1; kingbird, 2; field sparrow, 1; Carolina wren, 1; Maryland yellow-throat, 1; screech owl, 1; towhee, 1; English sparrow, 6; and last, but not least, a flourishing colony of 70 pairs of purple martins; in all a total of 24 species and 135 pairs on the 5 acres—the 1915 record for density of bird population.* The report of the 1914 bird counts credited Chevy Chase, Md., as having the highest record for that year. This same area in 1915 showed a satisfactory increase in the number of nesting birds, the kinds and the pairs of each being as follows: Southern robin, 19; Carolina chickadee, 2; tufted titmouse, 2; white-breasted nuthatch, 3; cedar waxwing, 2; cardinal, 2; song sparrow, 12; field sparrow, 1; goldfinch, 1; meadowlark, 1; blue jay, 3; red-headed woodpecker, 3; downy woodpecker, 1; screech owl, 1; bob-white, 1; purple grackle, 13; flicker, 3; mourning dove, 1; chipping sparrow, 9; towhee, 1; brown thrasher, 4; chimney swift, 3; house wren, 14; oven-bird, 1; yellow warbler, 1; Maryland yellow-throat, 2; redstart, 2; catbird, 17; wood thrush, 14; yellow-throated vireo, 4; red-eyed vireo, 11; kingbird, 1; crested flycatcher, 1; scarlet tanager, 2; indigo bunting, 1; orchard oriole, 1; Baltimore oriole, 1; wood pewee, 8; yellow- billed cuckoo, 1; English sparrow, 19; a total of 40 species and 189 pairs on 23 acres.