On the Road Again: Touring iNaturalist for roadkill observations as a new tool for ecologists


  • Shem Unger Biology Department Wingate University




roadkill, vertebrate biology, scavenging ecology, iNaturalist, biodiversity, road mortality, conservation


As human populations continue to increase and utilize highways, the potential negative impact of roadways on wildlife mortality (roadkill), is expected to increase accordingly. Documenting vertebrates killed on roadways can be time consumptive for local wildlife managers researching population trends of predominantly mammals and reptiles encountered. New citizen science observations taken on cell phones using the application iNaturalist provide a potentially powerful new tool to inform roadkill occurrence and its impact across taxonomic groups and geographic areas. To this end, I downloaded and surveyed data observations on iNaturalist for “road kill” and “dead on road” or “DOR”, within the United States, resulting in 17,926 total observations following database quality control, spanning 1973 to February of 2022. Overall of the 710 distinct species identified as roadkill, reptiles were the most frequently reported (12,127 observations), with eight of the top ten reported observations of roadkill being snakes. Mammals represented 3,094 observations followed by birds and amphibians, with 1,363 and 1,342 observations, respectively. Interestingly, I noted some difference for season of roadkill observations with summer having the highest reports of roadkill for both reptiles and amphibians, with more reports of mammals as roadkill in fall. This study contributes to our body of knowledge on roadkill ecology and can provide wildlife diversity biologist with a new avenue using citizen science data as this smartphone application becomes increasingly utilized for research on biodiversity.


Andrews, K. M., Gibbons, J. W., & Jochimsen, D. M. (2006). Literature synthesis of the effects of roads and vehicles on amphibians and reptiles. Washington DC. Federal Highway Administration (FHWA), U.S. Department of Transportation Report No. FHWA-HEP-08-005.

Aristeidou, M., Hererodotou, C., Ballard, H. L., Young, A. N., Miller, A. E., Higgins, L., & Johnson, R. F. (2021). Exploring the participation of young citizen scientists in scientific research: the case of iNaturalist. Plos one, 16, e0245682. https://doi.org/10/1371/journal.pone.0245682

Antworth, R. L., Pike, D. A., & Stevens, E. E. (2005). Hit and run: effects of scavenging on estimates of roadkilled vertebrates. Southeastern Naturalist, 4, 647-656. https://doi.org/10.1656/1528-7092(2005)004[0647:HAREOS]2.0CO;2

Bhandarkar, S., & Paliwal, G. (2021). Road kill of snakes (Squamata: Serpents) on state highway 276: a case study in protected forest area of Deori Forest range Gondia. Journal on New Biological Reports, 10, 7-10.

Chyn, K., Lin, T., Chen, Y., & Fitzgerald, L. (2019). The magnitude of roadkill in Taiwan: patterns and consequences revealed by citizen science. Biological Conservation, 237, 317-326. https://doi.org/10/1016/j.biocon.2019.07.014

Coelho, I. P., Teixeira, F. Z., Colombo, P., Coelho, A. V. P., & Kindel, A. (2012). Anuran road-kills neighboring a peri-urban reserve in the Atlantic forest, Brazil. Journal of Environmental Management, 112, 17-26. https://doi.org/10.1016/j.envman.2012.07.004

D’Amico, M., Roman, J., Reyes, L., & Revilla, E. (2015). Vertebrate road-kill patterns in Mediterranean habitats: Who, when and where. Biological Conservation, 191, 234-242. https://doi.org/10.1016/j.biocon.2015.06.010

Eloff, P., & Van Niekerk, A. (2008). Temporal patterns of animal related tragic accidents in the Eastern Cape, South Africa. South African Journal of Wildlife Research, 38, 153-162.

Erickson, W. P., Johnson, G.D., & Young, D. P. (2005). A summary and comparison of bird mortality from anthropogenic causes with an emphasis on collisions. USDA Forest Service General Technical Report PSW-GTR 191: 1029-1042.

Farmer, R. G. & Brooks, R. J. (2012). Integrated risk factors for vertebrate roadkill in southern Ontario. Journal of Wildlife Management, 6, 1215-1224. https://doi.org/10.1002/jwmg.358

Fox, S., Potts, J. M., Pemberton, D., & Crosswell, D. (2018). Roadkill mitigation: trialing virtual fence devices on the west coast of Tasmania. Australian Mammalogy, 41, 205-211. https://doi.org/10.1071/AM18012

Freitas, S.R., Sousa, C. O. M, & Bueno, C. (2013). Effects of landscape characteristics on roadkill of mammals, birds and reptiles in a highway crossing the Atlantic forest in southeastern Brazil. Proceedings of the 2013 International Conference on Ecology and Transportation. Arizona. 1-11.

Garriga, N., Franch, M., Santos, X., Montori, A., & Lorente, G. A. (2017). Seasonal variation in vertebrate traffic casualties and its implications for mitigation measures. Landscape and Urban Planning, 157, 36-44. https://doi.org/10/1016/j.landurbplan.2016.05.029

Grilo, C., Koroleva, E., Andrasik, R., Bil, M., & Gonzalex-Suarex, M. (2020). Roadkill risk and population vulnerability in European birds and mammals. Frontiers in Ecology and the Environment, 18, 323-328. https://doi.org/10.1002/fee.2216

Hastings, H., Barr, J., & Bateman, P. W. (2019). Spatial and temporal patterns of reptile roadkill in the north-west Australian tropics. Pacific Conservation Biology, 25, 370-376. https:doi.org/10.1071/PC18082

Heldin, J. O., & Petrovan, S. O. (2019). Effectiveness of small road tunnels and fences in reducing amphibian roadkill and barrier effects of retrofitted roads in Sweden. PeerJ, e7518. https://doi.org/10.7717/peerj.7518

Hobday, A.J., & Minstrell, M.L. (2008). Distribution and abundance of roadkill on Tasmanian highways: human management options. Wildlife Research, 35, 712-726.

Kreling, S.E., Gaynor, K. M., & Coon, C. A. (2019). Roadkill distribution at the wildland-urban interface. Journal of Wildlife Management, 83, 1427-1436. https://doi.org/10

Loss, S.R., Will, T. & Marra, P.P. (2014). Estimation of bird-vehicle collision mortality on U.S. roads. Journal of Wildlife Management, 78, 763-771. https://doi.org/10.1002/jwmg.721

MacKinnon, C.A., Moore, L. A., & Brooks, R. J. (2005). Why did the reptile cross the road? Landscape factors associated with road mortality of snakes and turtles in the south eastern Georgian Bay area. Proceedings of the Parks Research Forum of Ontario (PRFO) and Carolinian Canada Coalition (CCC) Annual General Meeting. 153-166.

Mo, M., & Mo, E. (2022). Using the iNaturalist application to identify reports of Green Iguanas (Iguana iguana) on the mainland United States of America outside of populations in Florida. Reptiles and Amphibians, 29, 85-92. https://doi.org/10.17161/randa.v29i1.16269

Nugent, J. (2018). iNaturalist: citizen science for 21st-century naturalist. Science Scope, 41, 12.

Periquet, S., Roxburgh, L., le Roux, A., & Collinson, W. J. (2018). Testing the value of citizen science for Roadkill studies: A case study from South Africa. Frontiers in Ecology and Evolution, 6, 15. https://doi.org/10.3389/fevo.2018.00015

Ratton, R., Secco, H., & Rosa, C. (2014). Carcass permanency time and its implications to the roadkill data. European Journal of Wildlife Research, 60, 543-546.

Rincon-Aranguir, M., Urbina-Cardona, N., Galeano, S. P., Bock, B. C., & Paez, V. P. (2019). Road kill of snakes on a highway in an Orinoco Ecosystem: landscape factors and species traits related to their mortality. Tropical Conservation Science, 12, 1-8. https://doi.org/10.1177/1940082919830

Rokop, M., Srikanth, R., Albert, M., Radonic, C., Vincent, R., & Stevenson, R. (2021). Looking more carefully: a successful bioblitz orientation activity at an Urban Public University. Citizen Science: Theory and Practice, 7, 1.

Santos, R. A. L., Ascensao, F., Ribeiro, M. L., Bager, A., Santos-Reis, M., & Aquiar, L. M. S. (2017). Assessing the consistency of hotspot and hot-moment patterns of wildlife road mortality over time. Perspectives in Ecology and Conservation, 15, 56-60. https://doi.org/10.1016/j.pecon.2017.2017.03.003

Schwartz, A. L.W., Williams, H. F., Chadwick, E., Thomas, R. J., & Perkins, S. E. (2018). Roadkill scavenging behavior in an urban environment. Journal of Urban Ecology, 4, 1-7. https://doi.org/10.1093/jue/juy006

Schwartz, A. L.W., Shilling, F.M., & Perkins, S.E. (2020). The value of monitoring wildlife roadkill. European Journal of Wildlife Research, 66, 18.

Selvan, K. M., Sridharan, N., & John, S. (2012). Roadkill animals on national highways of Karnataka, India. Journal of Ecology and the Natural Environment, 4, 363-365.

Shin, Y., Jeong, D., & Borzee, A. (2020). Mass displacement of Korean clawed salamanders (Onychodactylus koreanus) and the threat of road-kill. The Herpetological Bulletin, 151, 28-31. https://doi.org/10.33256/hb151.2831

Slater, F.M. (2002). An assessment of wildlife road casualties- the potential discrepancy between numbers counted and numbers killed. Web Ecology, 3, 33-42. https://doi.org/10.5194/we-3-33-2002

Snow, N. P., Andelt, W. F., & Gould, N. P. (2011). Characteristics of road-kill locations of San Clemented Island foxes. Wildlife Society Bulletin, 35, 32-39. https://doi.org/10.1002/wsb.4

Teixeira, F. Z., Coelho, A. V. P. , Esperandio, I. B., & Kindel, A. (2013). Vertebrate road mortality estimates: effects of sampling methods and carcass removal. Biological Conservation, 157, 317-323. https://doi.org/10.1016/j.biocon.2019.09.006

Theobald, E. J., Ettinger, A. K., Burgess, H. K., DeBey, L. B., Schmidt, N. R., Froehlich, H. E., Wagner, C., HilleRislambers, J., Tewksbury, J., Harsch, M. A., & Parrish, J. K. (2015). Global change and local solutions: tapping the unrealized potential of citizen science for biodiversity research. Biological Conservation, 181, 236-244. https://doi.org/10.1016/j.biocon.2014.10.021

Waetjen, D. P., & Shilling, F. M. (2017). Large extent volunteer roadkill and wildlife observation systems as sources of reliable data. Frontiers in Ecology and Evolution, 5, 89. https://doi.org/10.3389/fevo.2017.00089

Wilson, J.S., Pan, A. D, General, D. E. M., & Koch, J. B. (2020). More eyes on the prize: an observation of a very rare, threatened species of Philippine bumble bee, Bombus irisanensis, on iNaturalist and the importance of citizen science in conservation biology. Journal of Insect Communication, 24, 727-729. https://doi.org/10.1007/s10841-020-00233-3

Yue, S., Bonebrake, T. C. & Gibson, L. (2019). Informing snake roadkill mitigation strategies in Taiwan using citizen science. The Journal of Wildlife Management, 83, 80-88. https://doi.org/10.1002/jwmg.21580




How to Cite

Unger, S. (2022). On the Road Again: Touring iNaturalist for roadkill observations as a new tool for ecologists. Journal of Wildlife and Biodiversity, 6(3), 72–86. https://doi.org/10.22120/jwb.2022.300322.1479