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Bird Feeders and the Spatial Distribution of Ticks on aResidential Lawn in Worcester County, MassachusettsAuthor(s): John P. Kowalczyk and Tamara L. SmithSource: Northeastern Naturalist, 15(3):469-472. 2008.Published By: Eagle Hill InstituteDOI: http://dx.doi.org/10.1656/1092-6194-15.3.469URL: http://www.bioone.org/doi/full/10.1656/1092-6194-15.3.469

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NORTHEASTERN NATURALIST2006 13(1):39–42

Bird Feeders and the Spatial Distribution of Ticks on a Residential Lawn in Worcester County, MassachusettsJohn P. Kowalczyk1,* and Tamara L. Smith2

Abstract - In order to assess the effect of bird feeders on the distribution of ticks on a resi-dential lawn, ticks collected beneath bird feeders were compared to similar control areas on a residential property in Worcester County, MA. Host-seeking ticks were sampled from August 8, 2005 to July 25, 2007 by dragging with white fl annel cloth. All ticks were counted and removed from the cloth. Sampling was conducted 38 times. A total of 12 ticks (larvae and nymphs) was collected. Signifi cantly more ticks were collected from under the bird feeders (n = 10) than the control areas (n = 2).

The role of ticks as vectors of disease-causing pathogens is of signifi cance to both veterinary and human medicine. Of particular concern in the northeastern United States is Ixodes scapularis Say (Blacklegged Tick, more commonly referred to as Deer Tick). The Blacklegged Tick is a vector for human granulocytic ehrlichio-sis, babesiosis, and more commonly Lyme disease. Lyme disease is caused by the spirochete Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt and Brenner (Burgdorfer et al. 1982), which the Blacklegged Tick may acquire during a blood meal from an infected host. Larvae and nymphs often feed on Peromyscus leucopus Rafi nesque (White-footed Mouse), an important reservoir host of B. burgdorferi. Understanding the mechanisms that foster increasing human encounters with ticks has been an important part of coping with the problem. It is likely that many cases of Lyme disease result from encounters with ticks on the patient’s own property (Falco and Fish 1988) and that landscape features present on residential properties (ornamental vegetation, stone walls, woods, ecotone, and lawn) may infl uence the presence and distribution of ticks on those properties (Frank et al. 1998). It has been speculated that ground-feeding birds and rodents attracted to the seed falling beneath bird feeders may be the source of infected ticks. Leaving feed for birds (Smith et al. 2001) and the presence of a bird feeder (Orloski et al. 1998) were identifi ed as risk factors in case-control studies of the incidence of Lyme disease. Townsend et al. (2003) addressed this risk factor using statistical analysis of survey data as well as measurements of tick densities on residential properties and found no correlation between the presence of a bird feeder and the incidence of Lyme disease or the density of ticks. Our study was designed to investigate the relationship between bird feeders and tick distribution on a fi ner scale. If ticks detach or are dislodged from ground-feed-ing passerines and/or rodents foraging on the seed beneath bird feeders, there may be more ticks within 1 m of the feeders than areas of comparable size elsewhere on the lawn. We compared the number of ticks sampled directly beneath bird feeders with those from control areas ≈4 m distant. Study site. The site was a 0.5-ha residential property located in Mendon, Worcester County, MA. The CDC has classifi ed this county as a high-risk area for Lyme disease (CDC 2006). The property was mostly lawn with fruit trees, shade trees, ornamental shrubs and fl owers, stone walls, wood piles, and a small forest island (about 150 m2) as well as a vegetable garden (≈50 m2) and a shed. The property adjoined 0.7-ha of old fi eld characterized by Acer spp. (maples), Fraxinus americana L. (White Ash), Rhus spp. (sumacs), Populus deltoides Bartr (Quaking Aspen), Rhamnus cathar-tica L. (Common Buckthorn), and Ilex verticillata L. Gray (Common Winterberry Holly). It supported many tick host species: Microtus spp. (voles), Tamias striatus

Notes of the Northeastern Nat u ral ist, Issue 15/3, 2008

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L. (Eastern Chipmunk), Marmota monax L. (Woodchuck), Sylvilagus transitionalis Bangs (New England Cottontail Rabbit), Sciurus carolinensis Gmelin (Gray Squir-rel), Tamiasciurus hudsonicus Erxleben (Red Squirrel), Mephitis mephitis Shreber (Skunk), and White-footed Mouse. Vulpes vulpes L. (Red Fox), Canis latrans Say (Coyote), and Odocoileus virginianus Zimmermann (White-tailed Deer) have been seen on the property. The residential lot and adjacent old fi eld were surrounded by paved road (north and west), residential property (south), and commercial property (east). The lawn was mowed approximately weekly. No insect control products were applied to the lawn. Among the various bird species observed foraging on the study site were Cardinalis cardinalis L. (Northern Cardinal), Melospiza melodia Wilson (Song Sparrow), and Turdus migratorius L. (American Robin), birds reported to be infested with sub-adult Blacklegged Ticks (Hyland et al. 2000, Scharf 2004). Materials and methods. Nine birdfeeders were maintained throughout the prop-erty. A control area was designated at 6 m from each feeder. The controls were chosen to be in the same proximity to landscape features (e.g., ecotone, woodpiles, or stone walls) as the feeder. Each station was at least 5 m from the edge of the lawn. Seven of the feeders were suspended from 2.18-m Shepherd’s hook hangers: feeders 1 through 6 were cylindrical tube feeders (6.5 cm in diameter x 32 cm long) with six feeding perches from which birds of various sizes could feed, feeder 7 was a larger cylindri-cal feeder (10 cm in diameter x 45 cm long) with 2.54-cm wire mesh on which feed-ing birds could perch, feeder 8 was a house-shaped, wood and plexiglass feeder hung from the branch of a tree, and feeder 9 was a cylindrical feeder (6.5 cm in diameter x 36 cm long) designed to dispense thistle seed and hung from the end of a wooden swing frame. Each type of feeder was commonly available in the test area. Feeders 1–8 were fi lled with a seed mixture commercially available and designed to attract a variety of birds. The thistle feeder was fi lled with thistle. Feeder numbers 1 through 6 were erected at the start of this experiment; numbers 7, 8, and 9 had been in use on the property previously. A wheelbarrow was placed under the feeders during fi lling. Although this may not be typical, it limited the source of seed beneath the feeders to that caused by feeding, not fi lling. The locations were sampled with a 0.5-m2 fl ag. The fl ag consisted of a 1-m wide by 0.5-m long piece of fl annel cloth whose leading edge was tacked to a 1.05-m wooden dowel to which a 2-m length of nylon string was attached (Falco and Fish 1992). The fl ag was subsequently dragged over the surface in a circle with the spot directly below the feeder as the center. This procedure resulted in a sampled area of about 3.2 m2. The fl ag was dragged over the control area in the same manner. It was marked with a plastic tent peg at 1.1 m from the center. The fl ag was inspected for ticks after dragging at each station. All ticks were removed from the fl ag, preserved in alcohol, and identifi ed to species level (Keirans and Litwak 1989, Keirans et al. 1996). A total of 38 sampling events was spread out over 11 of the 24 months in that time period: August, September, and November of 2005; July, August, October, No-vember, and December of 2006; and May, June, and July of 2007.

Table 1. Amount and density of Ixodes scapularis collected at bird feeders and control areas on a residential lawn in Worcester County, MA.

Number (n) Larvae Nymph Adult Density (ticks/m2) Percent

Feeders 10 7 3 0 0.0091 83Controls 2 2 0 0 0.0018 17

Totals 12 9 3 0 0.0055*

*Average.

Northeastern Naturalist Notes2008 471

Results. A total of 12 live Blacklegged Ticks was collected. All of the ticks were collected in 2005 and 2007. There where signifi cantly more ticks collected from be-neath the feeders than from the control areas (Mann-Whitney, P = 0.035). Ticks were collected from under 6 of the 9 feeders (67%) and 2 of the 9 control areas (22%). All the ticks collected were sub-adults. The ticks from under the feeders were larvae (n = 7) and nymphs (n = 3), and those from the control areas were larvae (n = 2) (Table 1). Discussion. Our collection of only sub-adult stages is consistent with published data of ticks collected from passerines (Hyland et al. 2000, Scharf 2004) and small mammals (Mather et al. 1989, Schmidt et al. 1999) that indicate that sub-adult ticks are more likely than adults to parasitize smaller vertebrates. The possibility that rodents and medium-sized mammals could be attracted to the seed that falls beneath bird feeders has been considered by others (Orloski et al. 1998, Townsend et al. 2003). Host-seeking Blacklegged Tick nymphs are unlikely to travel far (<5 m) from where they have dropped off or were groomed off a vertebrate host (Carroll and Schmidtmann 1996, Falco and Fish 1991). We hypothesized that the activity of small mammals and birds foraging on the ground in the immediate vicinity of bird feeders on residential properties could affect the density of questing ticks relative to the rest of the lawn. Both birds and mammals can be potential sources of ticks found on lawns as well as vehicles for removal of ticks that may be questing there. If the net effect was to leave more ticks than they removed as our results indicate, it could increase the likelihood of residents being bitten as a re-sult of maintaining the feeders or engaging in other activities close to them. While the resulting distribution could increase the likelihood of residents of premises with bird feeders being bitten by a tick, it may not signifi cantly increase the risk of Lyme disease. Of the ticks collected from under the feeders, 70% (7/10) were larvae. Since Blacklegged Ticks usually do not acquire B. burgdorferi transovarially (Piesman et al. 1986), larvae are unlikely to be infected with the spirochete. The total number of ticks collected was low (n = 12), but the actual number of ticks present could have been higher because fl agging only captures a small propor-tion of the ticks present (Daniels et al. 2000). The low number of collected ticks may have also been due in part to the inhospitable nature of a typical residential lawn to tick survival. Manicured lawns can be a suitable environment for Blacklegged Ticks (Falco and Fish 1988), but are not ideal. The low humidity that results from the arti-fi cially maintained height of a lawn and subsequent lack of shade is consistent with high mortality (Jones and Kitron 2000, Stafford 1994) and reduced questing (Schulze et al. 2001). Further fi ne-scale sampling of residential properties with bird feeders should improve our understanding of how vertebrates attracted to the feeders affect tick distribution on such premises. Acknowledgments. We would like to thank W. Wyatt Hoback for his guidance at the inception of this project and two anonymous reviewers for comments on the manuscript.

Literature Cited

Burgdorfer, W., A.G. Barbour, S.F. Hayes, J.L. Benach, E. Grunwaldt, and J.P. Davis. 1982. Lyme disease: A tick-borne spirochetosis? Science 216(4552):1317–1319.

Carroll, J.F., and E.T. Schmidtmann. 1996. Dispersal of Blacklegged Tick (Acari: Ixodidae) nymphs and adults at the woods-pasture interface. Journal of Medical Entomology 33(4):554–558.

Center for Disease Control and Prevention (CDC). 2006. Reported Lyme disease cases by state, 1993–2005. Available online at http://www.cdc.gov/ncidod/dvbid/lyme/ld_rptdLymeCasesbyState.htm. Accessed April 17, 2007.

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Daniels, T.J., R.C. Falco, and D. Fish. 2000. Estimating population size and drag-sampling ef-fi ciency for the Blacklegged Tick (Acari: Ixodidae). Journal of Medical Entomology 37(3):357–363.

Falco, R.C., and D. Fish. 1988. Prevalence of Ixodes dammini near the homes of Lyme disease patients in Westchester County, New York. American Journal of Epidemiology 127(6):826–830.

Falco, R.C., and D. Fish. 1991. Horizontal movement of adult Ixodes dammini (Acari: Ixodi-dae) attracted to CO2-baited traps. Journal of Medical Entomology 28(5):726–729.

Falco, R.C., and D. Fish. 1992. A comparison of methods for sampling the Deer Tick, Ixo-des dammini, in a Lyme disease endemic area. Experimental and Applied Acarology 14:165–173.

Frank, F.H., D. Fish, and H. Moy. 1998. Landscape features associated with Lyme disease risk in a suburban residential environment. Landscape Ecology 13:27–36.

Hyland, K.E., J. Bernier, D. Markowski, A. MacLachlan, Z. Amr, J. Pitocchelli, J. Myers, and R. Hu. 2000. Records of ticks (Acari: Ixodidae) parasitizing birds (Aves) in Rhode Island, USA. International Journal of Acarology 26(2):183–192.

Jones, C.J., and U.D. Kitron. 2000. Populations of Ixodes scapularis (Acari: Ixodidae) are modulated by drought at a Lyme disease focus in Illinois. Journal of Medical Entomology 37(3):408–415.

Keirans, J.E., and T.R. Litwak. 1989. Pictorial key to the adults of hard ticks, Family Ixodidae (Ixodidae: Ixodoidea), east of the Mississippi river. Journal of Medical Entomology 26(5):435–448.

Keirans, J.E., H.J. Hutcheson, L.A. Durdan, and J.S.H. Klompen. 1996. Ixodes (Ixodes) scapu-laris (Acari: Ixodidae): Redescription of all active stages, distribution, hosts, geographical variation, and medical and veterinary importance. Journal of Medical Entomology 33(3):297–318.

Mather, T.N., M.L. Wilson, S.I. Moore, J.M.C. Ribeiro, and A. Spielman. 1989. Comparing the relative potential of rodents as reservoirs of the Lyme disease spirochete (Borrelia burg-dorferi). American Journal of Epidemiology 130(1):143–150.

Orloski, O.A., G.L. Campbell, C.A. Genese, J.W. Beckley, M.E. Schriefer, K.C. Spitalney, and D.T. Dennis. 1998. Emergence of Lyme disease in Hunterdon County, New Jersey, 1993: A case-control study of risk factors and evaluation of reporting patterns. American Journal of Epidemiology 147(4):391–397.

Piesman, J., J.G.Donahue, T.N. Mather, and A. Spielman. 1986. Transovarially acquired Lyme disease spirochetes (Borrelia burgdorferi) in fi eld-collected larval Ixodes dammini (Acari:Ixodidae). Journal of Medical Entomology 33(20):219.

Scharf, W.C. 2004. Immature ticks on birds: Temporal abundance and reinfestation. Northeast-ern Naturalist 11(2):143–150.

Schmidt, K.A, R.S. Osfeld and E.M. Shauber. 1999. Infestation of Peromyscus leucopus and Tamias striatus by Ixodes scapularis (Acari: Ixodidae) in relation and abundance of hosts and parasites. Journal of Medical Entomology 36(6):749–757.

Schulze, T.L., R.A. Jordan, and R.W. Hung. 2001. Effects of meteorological factors on diurnal questing of Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae). Journal of Medical Entomology 38(2):318–324.

Smith, G., E.P. Wileyto, R.B. Hopkins, B.R. Cherry, and J.P. Mayer. 2001. Risk factors for Lyme disease in Chester County, Pennsylvania. Public Health Report 16:146–156.

Stafford III, K.C. 1994. Survival of immature Ixodes scapularis (Acari: Ixodidae) at different relative humidities. Journal of Medical Entomology 31(2):310–314.

Townsend, A.K., R.S. Ostfeld, and K.B. Geher. 2003. Effects of bird feeders on Lyme disease prevalence and density of Ixodes scapularis (Acari: Ixodidae) in a residential area of Dutchess County, New York. Journal of Medical Entomology 40(4):540–546.

1Biology Department, Tri-County RVTHS, Franklin, MA 02038. 2University of Nebraska at Kearney, Bruner Hall, 905 West 25th Street, Kearney, NE 68849. *Corresponding author - kowalczykjp@unk.edu.