has progressed so far that attempts have been made to colonize it in the field, but the results of these colonizations will not be apparent for another season. Data are being secured on the prevalence of the wilt disease of the gipsy moth, but it has not been as abundant or destructive to the caterpillars this year as heretofore.

Silvicultural investigations on the sample plots are being continued. QUARANTINE WORK.-The inspection of forest and quarry products and nursery stock has been continued during the past year, although the volume of this material is not as large as that inspected heretofore. This is particularly true in connection with the shipments of nursery stock. From the number of gipsy-moth egg-clusters intercepted on material that was offered for shipment, it is evident that this work must be effectively and thoroughly performed if the insect is to be prevented from spreading to points outside the infested area.

SUMMARY.-The most severe infestation of the gipsy moth is at present in the Cape Cod district in Massachusetts. While the area infested by this insect has increased during the past year, the severity of infestation along and adjacent to the border is less severe than heretofore. The effectiveness of the imported parasites and natural enemies of both the gipsy moth and the brown-tail moth is increasing, although the severe winter conditions during the past year have been unfavorable to some of the species concerned. The area infested by the brown-tail moth has decreased materially, and the insect is not now seriously destructive except in limited localities.

Considering the area as a whole, conditions are favorable at the present time to bring about a marked decrease in the abundance and destructiveness of the gipsy moth.

REPORT OF CHIEF OF BUREAU OF BIOLOGICAL SURVEY.

UNITED STATES DEPARTMENT OF AGRICULTURE,

BUREAU OF BIOLOGICAL SURVEY,

Washington, D. C., August 29, 1918. SIR: I have the honor to submit herewith a report on the work of the Bureau of Biological Survey for the fiscal year ended June 30, 1918.

Respectfully,

Hon. D. F. HOUSTON,

Secretary of Agriculture.

E. W. NELSON,

Chief of Bureau.

WORK OF THE BUREAU OF BIOLOGICAL SURVEY.

The work of the Bureau of Biological Survey is conducted along five principal lines: (1) Investigations of the food habits of North American birds and mammals in relation to agriculture, in charge of Dr. A. K. Fisher; (2) biological investigations with special reference to the geographical distribution of native animals and plants, in charge of E. W. Nelson; (3) supervision of national mammal and bird reservations, in charge of G. W. Field; (4) enforcement of the Lacey Act regulating the importation of birds and the interstate shipment of game, in charge of W. F. Bancroft; (5) administration of the Federal migratory bird law, in charge of George A. Lawyer.

ECONOMIC INVESTIGATIONS.

The direct relation of the field work of this bureau to the increased production and conservation of food, through the destruction of predatory animals and injurious rodents, has been thoroughly demonstrated during the year. In response to war conditions the general plans of noxious-animal control were promptly modified in order to obtain the most direct results in reducing losses of live stock due to predatory animals, and in protecting cereal and other crops from their rodent enemies, and stored food supplies and other property from contamination and destruction by house rats. During the year the increasing number of requests received by the bureau for cooperation in new areas and for an extension of operations in territory where control campaigns are already in progress showed the rapid growth of public appreciation of this work.

The need for controlling noxious mammals is evident in view of the fact that predatory animals destroy annually more than $20,000,000 worth of live stock, mainly on the western ranges; noxious

rodents destroy not less than $150,000,000 worth of food crops each year, and the losses through the depredations of house rats exceed a yearly total of more than $200,000,000.

The bureau had available during the year for noxious-animal control from its regular appropriations and from emergency funds about $445,000. State officials, organizations, and individuals expended in cooperative work, largely under the direct guidance of the Biological Survey, more than $400,000. The State council of defense of New Mexico allotted $25,000 from its war fund to be used to stimulate food production by cooperating with this bureau. An equal sum under similar conditions was appropriated in May by a special session of the Arizona State Legislature. Largely increased amounts for cooperative work next year are promised in many places. Appropriations of this character and large sums allotted for cooperation with the bureau by live-stock and farmers' organizations and individuals in the territory where work is being done are indications of its practical usefulness. In addition much material was contributed and many thousands of farmers and stockmen joined in the field work.

PREDATORY ANIMALS AND RABIES.

During the year the bureau had available about $304,000 to be used in the destruction of wolves, coyotes, mountain lions, and other predatory stock-killing animals and for the suppression of rabies in wild animals. Rabies for some years has been widely prevalent in Washington, Oregon, California, Idaho, Nevada, and Utah. The general plan of organization for the predatory-animal and rabies work remains the same as during the preceding year. The Western States are divided into nine districts, each under an inspector, as follows: (1) Arizona-New Mexico, (2) California-Nevada, (3) Oregon-Washington, (4) Colorado, (5) Idaho, (6) Montana, (7) Utah, (8) Wyoming-South Dakota, (9) Texas.

Predatory animals are destroyed by a force of from 250 to 350 hunters under the direction of district inspectors. About one-fifth of these are paid from cooperative funds provided by the States or contributed by local organizations and individuals. The hunters are paid regular salaries and are permitted to receive no bounties. The skins of animals taken by Federal hunters become the property of the Government. The net proceeds already received for the skins taken during the year amount to $78,579.45, which has been turned into the Treasury. Skins remaining unsold will probably bring the entire receipts for pelts taken during the fiscal year to approximately $100,000.

Predatory animals are destroyed by trapping, shooting, den hunting during the breeding season, and poisoning. Poisoning campaigns were conducted on a larger scale than ever before and the results have been so satisfactory that they have received the strong support of cattle and sheep owners. Stockmen report that in the regions where poisoning campaigns have been conducted the usual severe losses from predatory animals during the lambing season have been materially reduced and, in many cases, practically eliminated. The largest poisoning operation in the West was carried on in the great sheep-growing region of southwestern Wyoming, where it covered

about one-sixth of the State. Another large area in southern Colorado was systematically poisoned with excellent effect. The experience gained in these operations indicates that with the full cooperation of local stockmen poisoning will prove a very important factor in disposing of the predatory-animal pest.

The following predatory animals were taken by hunters under the direction of this bureau, during the present year: 849 wolves, 26,241 coyotes, 85 mountain lions, 3,432 bobcats, 30 lynxes, and 41 bears. Every effort is being made to have the predatory-animal hunters kill only such bears as are known to be destructive to live stock. A small number of bears, however, unavoidably fall victim to traps set for other animals.

Since the bureau began its operations against predatory animals the skins of 70,732 have been taken and a vast number in addition have been killed by poison. Reports from various sections of the country where poisoning operations have been conducted show the finding of thousands of dead coyotes. The well-known fact that the great majority of poisoned animals are never found, coupled with the scarcity of coyotes in the poisoned areas, indicates the effectiveness of the work.

The control of rabies in the regions affected is under the supervision of the inspectors in charge of the regular predatory-animal work. Field reports indicate a continuance of this disease among wild animals, but show that the work of the bureau has been effective in limiting its spread and in suppressing it in many places. Although the disease occurs over a vast territory, the results of the work give promise of its eventual suppression without, as was at one time feared, its spreading over the entire Rocky Mountain region.

As an indication of the losses due to predatory animals it may be stated that the chairman of the State Live Stock Board of Utah estimates an annual loss in that region amounting to 500,000 sheep and 4,000,000 pounds of wool. The president of the New Mexico College of Agriculture, as a result of a survey of conditions in that State, estimates an annual loss there of 3 per cent of the cattle, or 34,000 head, and 165,000 sheep. A single wolf killed by one of the bureau hunters in southern New Mexico was reported by stock owners of that vicinity to have killed during the preceding six months 150 head of cattle valued at not less than $5,000. In July, 1917, two male wolves were killed in Wyoming which in May had destroyed 150 sheep and 7 colts. Another pair of wolves killed near Opal, Wyo., were reported to have killed about $4,000 worth of stock a year. Another Wyoming wolf, trapped in June, 1918, had killed 30 cattle during the spring. Exceptionally skillful hunters and trappers are detailed to capture these especially destructive animals as rapidly as they are reported, and the success in capturing them has resulted in a great addition to the meat output of the ranges.

RODENT CONTROL.

Injurious rodents, as prairie-dogs, ground squirrels, jack rabbits, and pocket gophers, mainly west of the Mississippi River, are in the aggregate enormously destructive to cultivated crops and native forage, thus directly reducing the food output from farms and lessening the carrying capacity of the range for live stock. The control

of noxious rodents, except on the public domain, is effected through cooperation with the States Relations Service of the Department of Agriculture and the extension service of State agricultural colleges. Cooperative campaigns of this kind are being conducted in North Dakota, Montana, Idaho, Washington, Oregon, Wyoming, Utah, Colorado, New Mexico, Arizona, and Virginia. This cooperation has proved to be extremely successful, as is shown by the increased number of farmers who join in the work each season. In addition to the rodent pests which abound in the more arid States of the West, several species are very destructive to certain crops and orchard trees throughout the East, where demonstration work for their control has given good results.

In order to secure accurate data as to the destruction of forage by rodents on the open range, field trial plots have been inclosed for the purpose in cooperation with the Forest Service and the Carnegie Institution of Washington. It is already apparent that important results will be secured from this investigation.

PRAIRIE-DOGS.

Measures for the destruction of prairie-dogs have been conducted by field parties operating on Government lands and by cooperative work with farmers and stockmen through the agricultural college extension services in New Mexico, Arizona, Colorado, Utah, Wyoming, Montana, and North Dakota. In all these States the campaigns have been under cooperative agreements with the State extension services, and in New Mexico the State Council of Defense has joined in the work and contributed funds to extend its scope. Farmers and stockmen are taking the greatest interest in the work as a direct method of saving crops and forage.

As an illustration of the effectiveness and economy of the methods of destroying these pests, a badly infested plot of 320 acres was chosen for a demonstration in northern Arizona. One man spent a day distributing poison over this area, at a total cost for labor and material of $9.79. The following day 1,641 dead prairie-dogs were picked up from this tract. With the number which must have died in their holes, there can be little question that more than 2,000 prairiedogs were destroyed in this experiment.

More than 3,500,000 acres of Government land have been practically freed from these pests.

GROUND SQUIRRELS.

Various species of ground squirrels extremely destructive to crops occur in enormous numbers over a large part of many of the Western States. The bureau has been engaged in a campaign for their control in cooperation with the State extension services in North Dakota, Montana, Idaho, and Wyoming; and introductory demonstrations leading toward similar campaigns have been made in several others of the cereal-producing States. In California there is also being conducted a campaign against these pests, with the State and county commissioners of horticulture and some county farm advisers cooperating.

The poisoned grain used in the campaigns to destroy ground squirrels on private lands is prepared under the supervision of field