Evaluation of plastic and Mylar flagging as repellents for snow geese (Chen caerulescens)

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repellents fr snw geese (Chen caerulescens) J.

1 USDA Natinal Wildlife Research Center Frm the SelectedWrks f Larry Clark 1994 Evaluatin f plastic and Mylar flagging as repellents fr snw geese (Chen caerulescens) J. Russell Masn Larry Clark Available at:

2 Evaluatin f plastic and Mylar flagging as repellents fr snw geese (Chert caerulescens) J. R. Masn* and L. Clark USDA/Animal and Plant Health Inspectin Service, Denver Wildlife Research Center, c/ Mnell Chemical Senses Center, 35 Market Street, Philadelphia, PA , USA The effectiveness f white flags, black flags and Mylar streamers as visual repellents t snw geese (Chen caerulescens) was evaluated. Five farms in Cumberland and Salem cunties, New Jersey served as test sites. At each farm, fur 1.12 ha fields were selected randmly, and then assigned t fur treatment cnditins: (a) white plastic flags (ne flag per.4 ha); (b) black plastic flags (ne flag per.4 ha), (c) Mylar streamers (ne streamer per.4 ha); and (d) stakes nly (ne stake per.4 ha). Frm 2 December 1992 t 24 March 1993, vegetatin samples and gse drppings were cllected in all fields. Drpping weights were significantly less in black- r white-flagged fields than they were in fields with Mylar streamers r bare stakes. Althugh vegetatin weights tended t increase in white- r black-flagged fields (and t decrease in fields with Mylar streamers r bare stakes), there were n significant differences. The results shw that white r black flags can ecnmically and effectively deter snw geese frm agricultural fields, at least when alternative grazing sites are available. Keywrds: gse; flagging; repellent Ppulatins f greater snw geese (Chen caerulescens atlantica) and reprts f crp depredatin by these birds are increasing thrughut the eastern United States (Annymus, 1981; Gauthier and Bedard, 1991). Althugh damage can ccur thrughut the winter, it is mst severe in late February and early March when the birds engage in premigratry fattening (Ankney, 1977). In New Jersey, rye, clver, winter wheat and grass turf are damaged, and farmers cmplain that vergrazing reduces crp yields (Bedard, Nadeau and Gauthier, 1986; Summers, 199; McKay et al., 1993). Damage als cmprmises nitrgen fixatin by rye and clver, and the ability f these cver crps t prevent wind ersin f the sil (Masn, Clark and Bean, 1993). Because geese are a vectr fr the transmissin f agriculturally imprtant pathgens and parasites (Masn et al., 1993), even farmers withut substantial gse damage t crps wrry abut visits by flcks t their fields. Chemical repellents such as methyl anthranilate may becme available fr gse damage cntrl (Cummings et al., 1991), but n substance currently is registered with the U.S. Envirnmental Prtectin Agency as a gse grazing deterrent. Existing legal cntrl strategies include hunting and harassment, planting unattractive cver crps and lure crps (Owen, 1978, 199; Gauthier and Bedard, 1991), and the use f auditry repellents (Cnver and Chask, 1985). Nne f these strategies is entirely effective, and additinal methds are being sught. One such methd may be the use f flags and streamers (Knittle and Prter, 1988; Heinrich and Craven, 199). *T whm crrespndence shuld be addressed /94/7/531-4 (~) 1994 Butterwrth-Heinemann Ltd During February and March f 1992, we evaluated the effectiveness f white flagging as a deterrent t snw gse grazing (Masn et al., 1993). During the 6- week trial perid, grazing damage in flagged fields was significantly less than it was in cntrl fields. This result is cnsistent with reprts cncerning the effectiveness f black flags and silver/red Mylar streamer tapes as waterfwl grazing deterrents (Knittle and Prter, 1988; Heinrich and Craven, 199; Summers and Hillman, 199). The present experiment was cnducted t evaluate whether white flags were mre effective than black flags r Mylar streamers as visual deterrents t snw geese. We suspected that differences might exist, since avidance f clurs (and, by extensin, flag types) may be species typical, there is n experimental evidence t supprt the use f black flagging, and Mylar streamer tape has been evaluated nly against Canada geese ( Branta canadensis). Materials and methds Study sites Five farms were selected in Cumberland and Salem cunties, New Jersey. On each farm, fur 1.12 ha fields, spaced at least.75 km apart, were selected randmly. This field size is cmmn fr New Jersey, a state where the average farm size is.6 ha (Bureau f Census, 1987). Selectin was based n a variety f agrnmic factrs including similarities f planting date, crp type, and barriers t the wind. Rye (Secale cereale) was planted in 16 fields, grass (Phleum sp.) in tw fields, and clver (Triflium sp.) in tw fields. Crp Prtectin 1994 Vlume 13 Number 7 5,31

Repellent flags: J.R. Masn and L. Clark Landwner reprts and ur wn bservatins between 1985 and 1992 indicated that all 2 fields cnsistently experienced grazing damage by snw geese.

3 Repellent flags: J.R. Masn and L. Clark Landwner reprts and ur wn bservatins between 1985 and 1992 indicated that all 2 fields cnsistently experienced grazing damage by snw geese. Prcedure On each f the five farms, the fur fields were randmly assigned t fur treatment cnditins (white flags, black flags, Mylar streamers, r cntrl stakes). These treatments were implemented n 24 and 25 Nvember Fr each field that received white r black flags, 25 rectangular flags were prepared by stapling plastic garbage bags ( cm) width-wise nt 1.2 m lengths f pine lathe. These flags were psitined in the ten fields in these tw treatment cnditins (n = five fields per cnditin). In all cases, ne flag was psitined in the centre f each acre (2.47 flags ha -1, 25 flags per field) t create a grid in accrdance with: (a) published recmmendatins fr the use f flagging as waterfwl deterrents (2.47 flags ha-]; Timm, 1983); and (b) prcedures fllwed during ur previus evaluatin f white plastic flags as snw gse deterrents (2.47 flags ha-l; Masn et al., 1993). The tp edge f each flag was ~.9 m abve the grund. Fr fields that received Mylar streamers,.9 m lengths f 1 cm wide red/silver Mylar tape were stapled width-wise t 1.2 m lengths f pine lathe. The streamers were psitined in the five fields in this treatment cnditin as described abve. Fr the five fields in the cntrl treatment, 1.2 m lengths f pine lathe were psitined as described fr flags and streamers. Within each f the 2 fields, fur transects were established between a randmly selected pair f adjacent lathe stakes. The endpints f each transect were marked by spraying the lathe with black paint. The length f each transect was measured using a Measure-master wheel (mdel n. MM3, Rlatape Crp., Spkane, Washingtn, USA). The mean transect length (+ standard errr) was m. Data cllectin began n 2 December 1992 and cntinued until 31 March By the end f the test perid, snw geese had migrated frm the study area. During the trial, n ther damage management technique was emplyed at any treated r cntrl field. Flags (white, n = 2, black, n = 1) and streamers (n = 6) were replaced during the curse f the trial when all flagging r streamer material had ripped free frm the lathe. At each visit t every field, the physical cnditin f flags and streamers was recrded. All fields were visited at 7-day intervals thrughut the test. During each visit, bservers walked the fur transects and cllected all gse drppings within 3 cm f the midline f the transect. In additin, at the centre f each transect, bservers cllected a vegetatin sample s that bimass culd be estimated. T accmplish this, the bserver tssed a.25 m 2 sampling frame ver his shulder and, using a pair f scissrs, cllected all f the abve-grund vegetatin within the frame. Sampling visits t each experimental and cntrl field lasted -- rain. After cllectin, drppings and vegetatin samples were immediately returned t the labratry, placed in a drying ven at 37 C fr 72 h, and then weighed. Weights were taken as indicatrs f gse numbers and grazing damage, respectively (Bedard et al., 1986; Summers, 199). Analysis We perfrmed a tw-way analysis f variance n ranks (Quade test; Cnver, 198) t determine whether the presence f geese at farms (as indicated by presence r absence f faeces) was different amng treatments. The blcks cnsisted f the nine sampling dates (2 January t 31 March) beginning with the first date that drppings were detected in fields. We used a tw-sided k-sample Smirnv test (Cnver, 198) t determine whether the snw gse pressure (as indexed by cumulative faeces per farm) differed acrss treatment types. Least squares regressins fr vegetative mass versus time were calculated fr the pre- and pstvisitatin perids fr each f the treatment types. Hetergeneity and tests f equality f slpes were estimated using a cvariance analysis (Snedecr and Cchran, 198) t reveal trends in vegetative grwth as a functin f the presence (r absence) f geese. Results Snw geese remained n the salt marshes and salt hay meadws near ur study sites until the end f January. At that time, geese were bserved mving nt surrunding agricultural fields in large numbers. This mvement was evident in ur index f field use by snw geese. The presence f geese n farms differed significantly as a functin f treatment (Quade test, t = 16, p <.1). Geese appeared n cntrl fields first, and cntinued t use these fields until their migratry departure. Next, geese were detected in fields with Mylar streamers. Finally, geese appeared in sme (but nt all) white- and black-flagged fields; this ccurred 4-5 weeks fllwing the first bservatin f geese in cntrl fields (Figure 1). Cnsidering nly thse fields used by geese, we fund that faeces mass differed amng treatments (Smirnv test, p <.25). The ttal cumulative faeces per unit length f transect was greater fr cntrl fields than fr fields with flags r Mylar streamers (Figure 2). Althugh vegetative bimass appeared t differ amng treatments, there was extreme variability within and amng sites. N transfrmatin was capable f eliminating this hetergeneity, and all slpes were statistically equal. Nevertheless, the data suggest that gse grazing negatively affected accumulatin f vegetative bimass, i.e. there was a tendency fr fields with geese t shw a zer r nn-psitive slpe, with the exceptin f fields with white flags (Figure 3). In this case, vegetative grwth appeared unaffected by the presence f geese. Discussin and management implicatins Snw gse drppings were first cllected in cntrl fields n 2 January and drpping weights frm these fields peaked n 3 March after a snwstrm. We 532 Crp Prtectin 1994 Vlume 13 Number 7

4 Repellent flags: J.R. Masn and L. Clark I White I.--// " I I I I I ' ',,, A D [] m It s34 '~t I Black r~ L-///I I I t~ 4 ~ I Mylar I I I v 3 2 :~ O ~ a Q) i i i i i i I i i i i! ~a i i i i i B ~ 8 /j~ a ~ n i i i i J i i i i i i i i i i i l C 1 3 m i e i......n _ A = ~ R - -.., m w W W W l _ i i i i l l J l l l l l l l l l D Time Figure 1. Number f farms (ut f a pssible five) where at least ne f fur transects cntained snw gse faeces. The panel inset depicts similarity amng treatments (underscre). Treatments were white plastic flagging, black plastic flagging, Mylar streamers, r bare (cntrl) stakes. Hrizntal ('13me) axis gives the date f bservatin (mnth/day) C~ 4. 3,5 3.O , i,,..... Date m m Figure 3. Vegetative bimass fr all transects sampled acrss all farms as a functin f sampling date fr cntrl (A), Mylar (B) black (C), and white (D) flagged fields. Fr panels A and B, pen circles and the assciated regressin (and upper and lwer 95% cnfidence limits) depict the relatinship between mass f sampled vegetatin per.25 m 2 and time fr the perid prir t the arrival f geese n fields. The pen squares and regressin depict the relatinship between vegetatin mass and time nce geese had arrived at the farms. Fr panels C and D, pen circles and the assciated regressin and cnfidence intervals (slid lines) depict the relatinship between vegetatin mass and sampling date fr the perid prir t the arrival f geese n fields. The slid squares and assciated regressin (dtted line) depict the vegetatin-time relatinship at thse farms visited by geese. The pen squares and assciated regressin (slid line) depict the vegetatin-time relatinship fr thse farms nt visited by geese during the perid when geese were visiting ther farms in the area 1. r,.) ~.5 N. Da~e Figure 2. Mean cumulative amunt f faeces per unit length f transect as a functin f sampling date. Treatments were white plastic flagging (@), black plastic flagging (i), Mylar streamers (i), r bare (cntrl) stakes ([~) cntinued t cllect drppings in cntrl fields until the last measurement date f the experiment (31 March). Fr Mylar fields, drppings were first fund n 2 February whereas in black- r white-flagged fields, drppings were first recrded n 16 and 23 February, respectively. Fewer f these fields were visited than either cntrl fields r fields with Mylar streamers. Nt surprisingly, cumulative faeces mass reflected the presence f geese in fields. Mean cumulative mass fr cntrl fields was significantly greater than the mean masses recrded fr flagged fields r fields with streamers. Crp Prtectin 1994 Vlume 13 Number 7 533

5 Repellent flags: J.R. Masn and L. Clark Althugh there was n statistically significant evidence f grazing damage, the present experiment des demnstrate that white r black plastic flags can effectively deter snw geese frm landing in fields. Mylar may als be effective fr this purpse. These findings are cnsistent with reprts cncerning the repellency f white flags (Masn et al., 1993) and Mylar streamers (Heinrich and Craven, 199; Summers and Hillman, 199). Because flags fashined frm garbage bags are cnsiderably less expensive than Mylar streamers (-US$.8 per unit versus US$1.2 per unit), we recmmend the frmer ver the latter. Further, we speculate that flagging may be even mre effective when cmbined with ther deterrent strategies, e.g. prpane cannns, harassment (Knittle and Prter, 1988; Heinrich and Craven, 199). Flagging may be a useful snw gse damage cntrl tl in lcatins ther than agricultural fields, and particularly when ther readily accessible feeding sites are available nearby. Fr example, flagging culd disperse geese in marshes where excessive grazing has substantial negative impacts (Kerbes, Ktanen and Jefferies, 199; Iacbeili and Jefferies, 1991; Hik, Jefferies and Sinclair, 1992). In a pilt test during the spring f 1993 (Dewey, 1993), results similar t thse reprted here fr upland agricultural fields were btained n a cmmercial salt hay meadw. We plan a mre extensive evaluatin f flagging in castal marshes during the winter f 1993/94. Acknwledgements We thank Shepherd Brthers Farms, Inc., Laning Brthers Farms, Inc., Maple Run/Level Acre Farms, Inc., Pplar Brands Farms, Inc., Srantin Farms, Inc., and Stella Farms, Inc. fr the use f their fields. J. Sillings, A. Mnteney, J. Flyd, C. Bggs and T. Casselman and S. Lewis helped install flags in fields. Funding was prvided by U.S. Department f Agriculture Cperative Agreement # [CA] between the Mnell Chemical Senses Center and the Denver Wildlife Research Center (DWRC). All prcedures were apprved by the DWRC Animal Care and Use Cmmittee. H.H. Heinrich f the New Jersey Farm Bureau prvided census infrmatin n average farm size. References Ankney, C.D. (1977) Feeding and digestive rgan size in breeding Lesser Snw Geese. Auk 94, Annymus (1981) A greater snw gse management plan. Can, Wildl. Serv. and U.S. Fish and Wildl. Serv., Atlantic Flyway Cuncil, Quebec, 26 pp Bedard, J., Nadeau, A. and Gauthier, G. (1986) Effects f spring grazing by snw geese n hay prductins. J. Appl. Ecl. 23, Bureau f Census (1987) Census f Agriculture, Vl. I, Gegraphic Area Series, Part 3, New Jersey State and Cunty Data, U.S. Department f Cmmerce, Washingtn, D.C.. 6 pp Cnver, W.J. (198) Practical Nnparametric Static'tics. Wiley, New Yrk, 493 pp Cnver, M.R. and Chask, G.G. (1985) Nuisance Canada gse prblems in the eastern United States, Wildl. Sc. Bull. 13, Cummings, J.L., Masn, J.R, Otis, D.L. and Heisterberg, J.L. (1991) Evaluatin f dimethyl and methyl anthranilate as a Canada gse repellent n grass. Wildl. Sc. Bull. 19, Dewey, J.A. (1993). The Effectiveness f Flagging as a Snw Gse Grazing Dewrrent in New Jersey Salt Marshes. Unpublished Master's thesis, Department f Bilgy, University f Pennsylvania, 32 pp Gauthier, G. and Bedard, J. (1991) Experimental tests f the palatability f frage plants in greater snw geese. J. Appl. Ecl. 28, Heinrich, J.W. and Craven, S.R. (199) Evaluatin f three damage abatement techniques fr Canada geese. Wildl. Sc. Bull. 18, 5-41 Hik, D.S., Jefferies, R.L. and Sinclair, A.R.E. 992) Fraging by geese, isstatic uplift and asymmetry in the develpment f saltmarsh plant cmmunities. J. Ecl 8, Iaebelli, A. and Jefferies, R.L. (1991) Inverse salinity gradients in castal marshes and the death f stands f Salix: the effects f grubbing by geese. J. Ecl. 79, Kerbes, R.H., Ktanen, P.M. and Jefferies, R.L. (199) Destructin f wetland habitats by lesser snw geese: a keystne species n the west cast f Hudsn Bay. J. Appl. Ecl. 27, Knittle, C.E. and Prter, R.D. (1988) Waterfwl Damage and Cntrl Methds in Ripening Grain: An Overview. U.S, Fish and Wildlife Service, Washingtn, D.C., 17 pp McKay, H.V., Bishp, J.D., Feare, C.J. and Stevens, M.C. (1993) Feeding by brent geese can reduce yield f ilseed rape. Crp Prt. 12, Masn, J.R., Clark, L. and Bean, N.J. (1993) White plastic flags repel snw geese (Chen caerulescens). Crp Prt. 12, Owen, M. (1978) Fd selectin in geese. Verh. rnithl. Bayern 23, Ges. Owen, M. (199) The damage--cnservatin interface illustrated by geese. Ibis 132, Snedecr, G.W. and Cchran, W.G. (198) Statistical Methds. Iwa State University Press, Ames, Iwa, 57 pp Summers, R.W. (199) The effect n winter wheat f grazing by Brent geese Branta bernicula. J. Appl Ecl. 27, Summers, R.W. and Hiilman, G. (199) Scaring brent geese Branta bernicla frm fields f winter wheat with tape. Crp Prt, 9, Timm, R.M. (1983) Preventin and Cntrl f Wildlife Damage. University f Nebraska Press, Lincln, Nebraska. 632 pp Received 2 September 1993 Revised 15 Nvember 1993 Accepted 16 Nvember Crp Prtectin 1994 Vlume 13 Number 7

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