Dispersal and home-range dynamics of exotic, male sika deer in Maryland

Content. An unknown number (n = four or five) and sex of sika deer (Cervus nippon yakushimae) were introduced to the Delmarva Peninsula, Maryland, in 1916. Since introduction, their population has grown exponentially. Aims. The purpose of our study was to investigate dispersal and home-range size to enable better management of this exotic species in the presence of native white-tailed deer (Odocoileus virginianus). Methods. We collected telemetry locations on 60 males (captured during their first winter) from 2008 to 2010. Animals were classified into three movement groups, including local, migratory and nomadic post-dispersal. Key results. Average home-range sizes ranged from 464 to 4121 ha and were influenced by season and deer movement grouping (P = 0.0001). Of 20 deer that dispersed, 19 did so at 1 year of age. Dispersal distance and direction were random across the landscape (P = 0.899). Local deer were the most common movement group (70%; 42 of 60) and were characterised by short movements confined to a well established home range. We observed 14 deer migrations, characterised by round-trip movements associated with seasons and directionality (P = 0.003). Four deer were classified as nomadic and had long-distance movements across the landscape unassociated with seasons. Conclusions. To aid managers in controlling the expansion of the population, we provide data regarding the manner, distance and direction that sika deer move. Our results show that sika deer have variable movement strategies and large home ranges. Implications. Variation in movement types will influence spread of the population, confounding species interactions, management and harvest strategies. The present results may have implications to other areas that also have sika populations.