2018 Northeastern Naturalist Notes Vol. 25, No. 1 N4 M.L. McCallum, et al. Arboreal Nesting by an Eastern Cottontail in a Suburban Setting Malcolm L. McCallum1,2,*, Angus A. McCallum1, Donald B. McCallum1, Donald B. McCallum Jr.1, Joseph M. McCallum1, Mary S. McCallum1, and Sherree A. McCallum1 Abstract - Sylvilagus floridanus (Eastern Cottontail) is a common lagomorph of the eastern US. Despite a bounty of literature on the nesting ecology of this mammal, reports of arboreal nesting are largely absent from the literature. We report the first observation of an arboreal Eastern Cottontail nest since a report in 1940. The previous observation was of a nest situated in the crotch of a Salix spp. (willow) in New York; nest success was questionable. Our observation was in a suburban backyard. The rabbit placed her nest ~2.5 m above the ground, up a vertical slope of tightly-wound twining Wisteria spp. (wisteria) stems. The nest was successful; the 4 litter mates continued to use the site for ~10 days after leaving the nest before moving elsewhere in the suburban environment. Sylvilagus floridanus (J.A. Allen) (Eastern Cottontail) is a common lagomorph found throughout much of the US. Eastern Cottontails typically nest in shallow depressions in the soil substrate that they line with grasses and fur (Chapman et al. 1982). Gestation varies from 25 to 35 days (Nowak and Paradiso 1983). The young make short trips from the nest beginning at 12–16 days and are weaned at 4–5 weeks of age (Chapman et al. 1982, Wainright 1969). When nesting in forested areas, such as Pinus (pine) plantations and orchards, Eastern Cottontails often place their nests near or against stumps and tree trunks with the opening facing away from the tree (Beule and Studholme 1942). Few accounts of arboreal behavior in lagomorphs exist. In Australia, Oryctolagus cuniculus (L.) (European Rabbit) is known to climb 7 m into tree canopies in search of food (Anonymous 1893, 1950; Parliament of New South Wales 1902). The closely related Sylvilagus bachmani Waterhouse (Riparian Bush Rabbit) also reportedly climbs trees (USFWS 2011). Recently, an observation of an Eastern Cottontail resting in a tree made news in Toronto, ON, Canada (Bream 2015), and the report quoted Rudy Boonstra (University of Toronto, ON, Canada) as “never having seen a rabbit in a tree in 30 years”. There is only 1 previous report of an Eastern Cottontail nest in an arboreal setting (Shadle et al. 1940). This nest was ~2.9 m above the ground in a Willow (Salix spp.) located 64 m (210 ft) from the bank of the Niagara River’s east branch. The willow was tilted ~48° from perpendicular (i.e., 42° from the ground) thus, allowing the mother to easily climb into the crotch of the tree where she placed her nest. The nest originally contained 6–7 day-old young, of which 2 remained a week later. Unfortunately, the authors discovered this nest by stepping on it while climbing the tree, confounding the surv ivorship observations. On 10 June 2008, we observed an adult Eastern Cottontail climb up a 2.5-m vertical slope of Wisteria spp. stems that grew on an arbor above a swing (Fig. 1) located at 38°42' 40.1''N, 89°56'49.05''W (Madison County, IL). After further investigation, we discovered a nest of furred young. After about 2 days, we observed 4 young rabbits moving back and forth between the arboreal nest and the ground. After a week, neither the mother nor the young returned to the nest, and after ~10 days we assumed that the animals had moved elsewhere in the suburban environment. 1103 Rex Drive, Collinsville, IL 62234. 2Current address - Agriculture and Applied Sciences, Cooperative Research, Education and Extension, PO Box 1500, Langston, OK 73050. *Corresponding - malcolm.mccallum.tamut@gmail.com. Manuscript Editor: John Litvatis Notes of the Northeastern Naturalist, Issue 25/1, 2018 N5 2018 Northeastern Naturalist Notes Vol. 25, No. 1 M.L. McCallum, et al. Figure 1. Location of an arboreal nest of an Eastern Cottontail. Photogr aph © Mary McCallum. This observation raises the question of whether arboreal nesting behavior of the Eastern Cottontail is more common than previously thought, or if these occurrences are unique and unusual outliers. Although arboreal nesting is probably not commonplace, the lack of observations may reflect either its rarity or investigator bias, in which arboreal settings are ignored by investigators. The original 1940 observation and our report provide evidence 2018 Northeastern Naturalist Notes Vol. 25, No. 1 N6 M.L. McCallum, et al. that those studying Eastern Cottontails should consider arboreal settings as potential nesting sites. The location of the 1940 nest was in an area that likely flooded frequently. The area around the recent observation is replete with dangers including lawnmowers, dogs, cats, and people. A more in-depth consideration of arboreal ecology of the Eastern Cottontail may reveal an important niche that was previously unrealized. Acknowledgments. Yonathan Tilahun, Steve Zeng, and Steve Hart reviewed this manuscript prior to submission; we are grateful for their comments and feedback. Literature Cited Anonymous. 1893. Our duty towards vermin. The Saturday Review, 5August:156–157. Anonymous. 1950. Rabbits can and do climb trees. The Advertiser, Tuesday 17 January:1. Beule, J.D., and A.T. Studholme. 1942. Cottontail rabbit nests and nestlings. Journal of Wildlife Management 6:133–140. Bream, M. 2015. Wildlife in the city: The strange habits of rabbits. The Star. 21 March. Available online at https://www.thestar.com/news/insight/2015/03/21/wild-in-the-city-the-strange-habitsof- rabbits.html. Accessed 22 March 2017. Chapman, J.A., J. Hockman, J. Gregory, and W.R. Edwards. 1982. Cottontails: Sylvilagus floridanus and allies. Pp. 83–123, In J.A. Chapman and G.A. Feldhamer (Eds.). Wild Mammals of North America. The Johns Hopkins University Press, Baltimore, MD. 1232 pp. Nowak, R.M., and J.L. Paradiso. 1983. Walker’s Mammals of the World. 4th Edition. The Johns Hopkins University Press, Baltimore, MD. 2015 pp. Parliament of New South Wales. 1902. Rabbit Pest Bill: Second Reading. Parliamentary Debates. Legislative Council and Legislative Assembly 22:2279–2287. Shadle, A.R., T.S. Austin, and F.X. Meyer. 1940 Five Cottontail Rabbits up a tree. Journal of Mammalogy 21:462–463. US Fish and Wildlife Service (USFWS). 2011. Rabbit rescue at San Joaquin River National Wildlife Refuge. Open Spaces, A Talk on the Wild Side. Available online at https://www.fws.gov/news/ blog/index.cfm/2011/11/28/Rabbit-Rescue-at-San-Joaquin-River-National-Wildlife-Refuge. Accessed 22 March 2017. Wainright, L.C. 1969. A literature review on cottontail reproduction. Special Report 19. Colorado Department of Game, Fish, and Parks, Denver, CO.