BOSTON PUBLIC LIBRARY 3 9999 063 7 726 3 / BIRD DAMAGE TO BLUEBERRIES IN THE UNITED STATES /7^ ■sup; --CS ORY UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE BUREAU OF SPORT FISHERIES AND WILDLIFE Special Scientific Report-Wildlife No. 172 UNITED STATES DEPARTMENT OF THE INTERIOR Fish and Wildlife Service Bureau of Sport Fisheries and Wildlife BIRD DAMAGE TO BLUEBERRIES IN THE UNITED STATES D. F. Mott and C. P. Stone Denver Wildlife Research Center Division of Wildlife Research Bureau of Sport Fisheries and Wildlife Special Scientific Report — Wildlife No. 172 Washington, D.C. • 1973 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C, 20402 - Price 66 cents Stock Number 2410-00376 CONTENTS Page Abstract ii Introduction 1 Questionnaires 1 Results 2 Acreage grown 2 Severity of bird damage 2 Bird species and damage patterns 2 Crop protection 3 Economic importance of bird damage 4 Conclusions 4 References 5 Tables 6 Appendix I 11 ABSTRACT In 1972, a questionnaire on bird damage to highbush blueberries was sent to 78 individuals knowledgeable about the blueberry crop in 14 States. According to 42 replies with opinions, birds were conservatively estimated to damage 5 percent of the crop. This represents a nationwide loss between $1.6 and $2.1 million. Starlings (Stumus vulgaris) , robins (Turdus migratorius) , and common grackles (Quiscalus quiscula) were considered the most damaging species. Gas-operated exploders, shooting, protective net- ting, trapping, and electronic devices were listed most frequently as effective methods of reducing bird damage. U INTRODUCTION Although knowledge of the extent and distribution of bird damage is important in assigning priorities for research on prevention, little is known about the damage to agricultural crops done by birds in the United States. Bird damage to highbush (cultivated) blueberries has been estimated for Massachusetts by Pearson (1958) and Smith (1963) and for individual fields by Hayne and Cardinell (1949), Schwartze and Alcom (1960), and Vaile and Moore (1968), but there has been no quanti- tative information on the nationwide extent of this problem. Rough esti- mates by those familiar with the blueberry industry have suggested that the losses are sizable. Phillip Sheridan, Executive Secretary of the North American Blueberry Coxmcil, has stated (personal conmiTinication, January 17, 1972) that as much as 10 percent of the United States blue- berry crop, or about 2 million dollars worth, is lost to birds each year. To better define bird damage to cultivated blueberries in the United States, a questionnaire was sent to knowledgeable individuals in the blueberry-producing states. The information gathered is reported herein. QUESTIONNAIRES In August 1972, 78 questionnaires, with covering letters and self-addressed return envelopes, were mailed to three to eight indi- viduals in each of 14 States where highbush blueberries are grown. A sample questionnaire and covering letter are reproduced in Appendix I. Those receiving questionnaires included State Agricultural Extension personnel; State fish and game personnel; biologists from the Division of Wildlife Services and Special Agents from the Division of Law Enforcement, U.S. Bureau of Sport Fisheries and Wildlife; blueberry researchers listed in the Directory of North American Blueberry Research (compiled by the North American Blueberry Council); and officers of the North American Blueberry Council and Oregon Blueberry Growers Associa- tion. In December 1972, a follow-up letter and a duplicate question- naire were mailed to recipients who returned inadequate responses or failed to respond. Altogether, 42 questionnaires (54%) were completed and returned. Some recipients had forwarded the questionnaire to an authority in their State who they believed was better qualified. Responses from individual States ranged from one to six. RESULTS Acreage grown. — Respondents were asked to estimate the acreage of highbush blueberries grown in their State. Their estimates indicate that 21,295 to 28,105 acres are grown in the 14 States (Table 1). Michigan and New Jersey together accounted for at least half the total; North Carolina ranked third. Although the southeastern States now pro- duce only a fraction of the United States crop, research in breeding varieties for wann climates could markedly increase future acreages in those States (Sharpe and Sherman 1971). In the West, about 1,000 acres of blueberries are grown in Washington and Oregon. Severity of bird damage. — Of the 42 respondents, 20 rated bird damage to highbush blueberries as a serious problem, 17 rated it as moderate, 4 rated it as slight, and 1 rated it as nonexistent (Table 1). The lone report of no damage came from Vermont , while the other respond- ent from that State considered the problem serious. Contradictory responses usually came from States where blueberries are a minor and relatively unknown crop. Overall, bird damage appeared to be a moderate to serious problem in eight States — Arkansas, Indiana, Louisiana, Massachusetts, Michigan, New York, Oregon, and Washington — and a slight to moderate problem in six — Florida, Georgia, New Jersey, North Carolina, Rhode Island, and Vermont. Respondents considered bird damage to blueberries during the 1972 season to be worse than usual in Arkansas, North Carolina, Oregon, and Rhode Island; the same or worse than usual in Indiana, Michigan, New Jersey, and Washington; the same as usual in Florida, Louisiana, New York, and Vermont; and the same or less than usual in Georgia and Massachusetts. Increased use of protective netting in Massachusetts was listed as a reason for lessened damage. In Michigan, increased damage appeared to be the result of a late spring freeze that destroyed many wild fruits and 60 to 75 percent of the blueberry crop. Reduced fruit production probably concentrated birds in the productive plantings. Most respondents reported that losses to birds were more severe than losses to insects, hail, frost, wind, or rain (Table 2). Again, Michigan was an exception. Bird species and damage patterns. — The species most often reported as being responsible for blueberry damage were, in order of frequency, starlings (Stumus vulgaris) , robins (Turdus migratorius) , and common grackles (Quiscalus quiscula) (Table 1) . Starlings were considered the most damaging species in Georgia, Indiana, Michigan, New Jersey, New York, North Carolina, Rhode Island, and Washington; robins, in Arkansas, Massachusetts, New Jersey, New York, and Oregon; and grackles, in Rhode Island. House finches (Carpodacus mexicanus) were considered most damaging by one respondent each in Washington and Oregon; cedar waxwings (Bombycilla cedrorum) and scrub jays (Aphelocoma coerulescens) were also listed as contributing to blueberry damage in Oregon. In the East, addi- tional species listed were blue jays (Cyanocitta cristata) , mockingbirds (Mimus polyglot tos) , gray catbirds (Dumetella carolinensis) , brown thrashers (Toxostoma rufum) , red-winged blackbirds (Agelaius phoeniceus) , brown-headed cowbirds (Molothrus ater) , cardinals (Richmondena cardinalis) , common flickers (Colaptes auratus), crows (Corvus spp.)> meadowlarks (Stuimella spp.)> orioles (Icterus spp.)> and unspecified woodpeckers. Most respondents indicated that the main factors influencing bird damage were an abundance of birds and the location of blueberry fields near vegetation attractive to birds (Table 3). A lack of alternative foods was also thought important. Some suggested that small orchards received more damage than larger ones; this belief is reasonable because, per unit of fruit grown, small orchards usually have more border, pro- viding more nesting and loafing cover for birds. Most respondents believed that birds damage only ripening fruit, but damage to buds was mentioned as a problem in some plantings in Indiana, Massachusetts, New Jersey, New York, Oregon, and Rhode Island. One respondent observed evening grosbeaks (Hes periphona vespertina) taking blueberry buds in New York. In Florida, crows were blamed for breaking branches in addition to damaging ripening berries . Crop protection. — Gas-operated exploders, shooting, protective netting, trapping, and electronic scaring devices were listed most frequently as effective methods of reducing damage (Table 4) . Netting was listed as one of the most effective methods of reducing damage and seemed especially popular in States with relatively small acreages of blueberries such as Arkansas, Louisiana, Massachusetts, Rhode Island, and Vermont. Growers in States with large acreages did not use nets as frequently, possibly because their fields were too large or because netting interfered with sprinkler systems, machine cultivation, and picking. The high cost, up to $1,000 per acre, was also listed as a deterrent to netting. Av-Alarm,'^ which produces a synthesized sound for scaring birds, was one of the most frequently used electronic devices in Indiana, Michigan, and New York. A respondent in New York reported that one blueberry grower stocked cats in his orchard as a means of damage prevention. Parathion was reported as being used as a poison in New York and New Jersey. Most respondents indicated that they did not know the amount of money spent on bird damage prevention in their State. The highest amoiint reported was for Michigan, where respondents estimated that at least $250,000 was spent for traps, electronic devices, exploders, and shotgun shells. In Florida, one blueberry researcher reported spending $1,000 per acre to cover his test plots with nets. In Oregon, growers were reported to have spent $25 to $800 an acre for protection. In North Carolina, one respondent spent $200 for shotgun shells in 2 weeks, and Reference to trade names does not imply endorsement of commercial products by the Federal Government. another estimated that a total of $2,000 was spent to alleviate damage. In Indiana, one respondent reported that $75 was spent in attempting to protect one 5-acre field. Economic importance of bird damage. — Respondents in nine States supplied quantitative estimates of the amount of bird damage. Reported losses in the three largest blueberry-producing States were 6 to 20 percent in Michigan, 5 percent in New Jersey, and 10 percent in North Carolina. No Statewide estimate was given for Florida, but losses up to 100 percent were reported in some test plots. In Louisiana, birds were reported to have destroyed one-third of the blueberries not covered with netting. In Indiana, a loss of 60 tons of blueberries worth $30,000 was attributed to birds. Respondents in Massachusetts reported that surveys by growers showed losses of $16,347 in 1967 and $4,136 in 1971. In Oregon, respondents estimated losses of 40 to 60 percent of the state's crop. In Washington, statewide loss estimates ranged from 5 to 29 percent, but local losses were sometimes more serious; an 80 percent loss was reported on test plots in one area, and four growers reported that, even with control practices, they lost over 30 tons of blueberries ($15,000). Although most of these reported losses are estimates, they appear to be realistic. Field surveys have shown similarly high figures. Vaile and Moore (1968) found that bird damage to one variety of blueberries in experimental plots in Arkansas resulted in a gross income loss of $1,855.50 per acre. Stone (impublished data) reported that birds damaged 44.2 percent of the blueberries in the untreated half of a 3-acre Michigan test field in 14 days. CONCLUSIONS Obtaining quantitative samples of bird damage to blueberries to pro- vide a statistical basis for estimating total loss of the crop in the United States would be a formidable and expensive task. However, pro- jecting the subjective results of this questionnaire survey will help one comprehend the amount of bird damage to blueberry crops in the United States. If the estimated 21,295 to 28,105 acres of blueberries grown in the United States (Table 1) produced the national average of 3 tons of berries per acre and were worth $500 per ton (Wohld, 1967), then the annual value of the United States blueberry crop would be between $31.9 and $42.2 million. A conservative estimate of the annual loss to birds of 5 percent of the crop would cost United States growers between $1.6 and $2.1 million a year. REFERENCES Hayne, D. W., and H. A. Cardinell 1949. Damage to blueberries by birds. Michigan Agric. Sta. Quart. Bull. 32(2) : 213-219 . Pearson, E. W. 1958. A study to find the cause and remedy for bird damage to cultivated blueberries in Massachusetts. M.S. Thesis. Univ. Massachusetts, Amherst. 92 pp. Schwartze, C. D., and G. D. Alcorn 1960. House finches' feeding menaces cultivated blueberries. Murrelet 41(1): 8-9. Sharpe, R. H., and W. B. Sherman 1971. Breeding blueberries for low-chilling requirement. Hort. Sci. 6(2): 3-5. Smith, R. N. 1963. A study of environmental and population factors in relation to damage to orchards caused by birds. M.S. Thesis. Univ. Massachusetts, Amherst. 132 pp. Vaile, J. E. , and J. N. Moore 1968. Bird damage to blueberries. Arkansas Farm Research, Arkansas Agric. Exp. Sta., Univ. Arkansas, Fayetteville, Arkansas . 1 pp • Wohld, M. L. 1967. Blueberries: a $5,000-plus an acre crop. Oregon Farmer Magazine, July: 6-8. m 01 •H i-i l-i 01 J3 0) 3 T3 0) 60 nj B -O S-l •H tU J2 O 0) M-l o (1) 00 00 CO 4-) T3 tn ■H t3 -H •H to m 0) a) •H M-l o o -) s 2; o a u o a o 00 0) o T3 a to C H 0 en ■u i-i u 60 d C a) 0 •H 0 g CO ^ (1) > g o H TABLE 2. — Comparison of bird damage with other types of losses to cultivated blueberries in 14 States. Number of respondents reporting bird damage as More Do not serious Similar Less know Other tjrpes of losses Insects Hail Frost Wind Rain 26 24 17 26 24 2 5 9 1 2 14 2 9 13 - 2 13 - 4 13 TABLE 3. — Factors influencing bird damage to cultivated blueberries in 14 States, Number of respondents listing as factors influencing bird damage Proximity of Distance State Abxindance attractive Alternative Orchard to other Other of birds vegetation foods size orchards Arkansas 1 Florida 1 1 Georgia 2 1 Indiana 2 1 Louisiana 2 3 Massachusetts 2 4 Michigan 4 6 New Jersey 3 4 New York 1 1 North Carolina 2 1 Oregon 3 2 Rhode Island 1 Vermont 1 Washington 2 1 2 4 4 2 2 1 1 1 1 1 1 2 2 4 3 2 1 1 1 water supply 1 water supply Total 27 25 18 16 CO u o a w T) o (U 0) CO H 3 M-l (U CO Pi T3 O rCl CD 4J [5 (U Q s M o CD (1) to vj CO M CJ C c/: •rl 4J M CO O o p. •r( 0) C VJ o M to JJ ■l-l O fl m ^ •rt rQ O c o c 9 o o CO Xi ^ 0) CO •H CO •r^ u o 0) M a CO fl U o •H 4J 0) •rl M cU 1) O •H O CO rH m !>^ & C ftT3 ft O a) ft CN CM ^1 ro ?>l ^1 fn| . CU CO CO (U w CO fl 3 C! CO CO CO CO CO CO CO ^ CO M 4-1 CO TS •H c •H a 00 (U CO c •H 00 CO CO CO •H 1-2 CO M u •H •rl CO x: ^ O o 13 3 CO a *5 >•< rH CU C o S CD -l n) PI zj ^3 o § c M rH o CO CO 4J U M 4-1 00 c C c J3 o (U o •H 4J 00 T3 e x: V4 CU O u CO o u ^ CU CO 2: o > s CO 4J o H APPENDIX I United States Department of the Interior FISH AND WILDLIFE SERVICE BUREAU OF SPORT FISHERIES AND WILDLIFE BUILDING 16, DENVER FEDERAL CENTER DENVER, COLORADO 80225 August 14, 1972 Dear The Denver Wildlife Research Center is compiling data on the extent and distribution of agricultural losses caused by birds . Unless the importance of these losses are known, we cannot properly establish research and management priorities. For this reason, we ask that you take the time to fill out the attached questionnaire on Bird Damage to Blueberries as completely as possible. If you believe there is someone else in your state more capable of answering the questions, please either consult with him or forward the question- naire. We ask, however, that those who answer questions give their name and affiliation. Thank you for your cooperation. Sincerely, Donald F. Mott Research Biologist Section of Birds Attachment 12 QUESTIONNAIRE ON BIRD DAMAGE TO BLUEBERRIES 1. Do you think bird damage to blueberries in your state is; a. A serious problem? b. A moderate problem? c. A slight problem? d. No problem? ^ Comments 2. What bird species are involved in blueberry damage in your state? Indicate importance of each (e.g., 1st, 2nd, etc.): a. Starlings? b. Robins? c. Crackles? d. House Finches? e. Others? Please list Comments 3. What method is currently employed to reduce bird damage to blueberries: a. Shooting of offending birds? b. Netting of blueberries? c. Traps? d. Poisons? Which? e. Nest removal? f. Exploders? g. Electronic scare devices (e.g., Av-Alarm, Biosonics)? h. Reflectors? i. Scarecrows? i. Other? Which? Comments 13 4. Which of the above methods do you think is: a. Most frequently used? b. Most effective? Comments 5. What do you feel are factors influencing bird damage to blueberries? a. Size of the orchard? b. Proximity of orchard to vegetation attractive to birds? c. Distance to neighboring orchards? d. An abundance of birds? e. Alternative wild foods? f. Other? Which? Comments 6. Is bird damage to blueberries this year more or less, or about the same as that usually experienced? Comments 7. Is bird damage to blueberries limited only to ripening fruit? Or, do the birds attack the buds also? Comments 8. How do you rate bird damage to blueberries with other types of losses? More Similar Less Don't Know Insects Hail Frost Wind Rain Comments 14 9. Do you have any loss figures on a state, cotjnty, or field basis for bird damage to blueberries? If so, please indicate percent or dollar loss, species of birds involved, and source of your information. Comments 10. Do you have an estimate of the amount of money spent on bird damage prevention for blueberries on a local or statewide basis? Comments 11. Do you have an estimate of the number of acres of blueberries grown in your state? Comments Name Affiliation ]_5 ■& U.S. GOVERNMENT PRINTING OFFICE : 1974 0-529-347 As the Nation's principal conservation agency, the Department of the Interior has basic responsibiUties for water, fish, wildlife, mineral, land, park, and recreational resources. Indian and Ter- ritorial affairs are other major concerns of this department of natural resources. The Department works to assure the wisest choice in managing all our resources so that each shall make its full contribution to a better United States now and in the future. UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE BUREAU OF SPORT FISHERIES AND WILDLIFE WASHINGTON. D. 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