Movements, habitat selection, and home ranges of greater sandhill cranes (Grus canadensis tabida) in Ohio
Jason T. Tucker, MS
Advisor: Robert Gates
The Greater sandhill crane (Grus canadensis tabida) historically inhabited Ohio until its extirpation from the state in the 1930s due to habitat loss and unregulated hunting. About fifty years later in the 1980s, the first breeding pair was discovered in Wayne County, OH and the breeding population has since continued to grow and expand. The first systematic study of Ohio’s cranes was conducted during 2002-2004 but seasonal movements, habitat selection, and migration behavior were largely unstudied in this breeding population.
Road surveys, ground searches, and opportunistic aerial surveys were conducted during 2011-2013 to locate cranes and to determine their local movements and distribution in northeast Ohio. Unison calls were infrequently heard during road surveys and visual observations were rare. Two observations of breeding pairs or family units were made during ground searches and aerial surveys at Killbuck Marsh and Funk Bottoms Wildlife Areas (KMFB) in Holmes and Wayne Counties, OH in 2011, but observations of 11 breeding pairs were recorded in 2012 and again in 2013.
Ohio Breeding Bird Atlas II (OBBA II) data also were evaluated to investigate the statewide distribution of the crane population during 2006-2011. One hundred seventy of these OBBA II records included GPS locations. Thirty records were of breeding pairs and 56 were of family units. Forty of the total records were concentrated within approximately 50 km of KMFB. Thirty-one OBBA II recorded sightings were concentrated in northeast Ohio, in Geauga and Trumbull counties; and 20 were concentrated near the marsh refuges of western Lake Erie.
Twenty-three cranes were captured and equipped with transmitters during 2011-2013 at KMFB in Holmes and Wayne Counties, OH to track their local movements, seasonal habitat selection, and migration behavior. Cranes followed the general migration path of the Eastern Population of cranes in the Mississippi and Atlantic Flyways. Important stopover locations included Muscatatuck National Wildlife Refuge, IN, Hiwassee Wildlife Refuge, TN, and private lands in north-central and northeastern Florida. Not all cranes migrated each year, some choosing to remain in northeast Ohio through the winter. Juveniles returned with their parents after their first winter and dispersed soon after returning, eventually settling with the summering flock of nonbreeding adults at Funk Bottoms Wildlife Area (FBWA). Mean home range size of breeding adults was 193 ha (95 CI = 242) during the nesting seasons and 874 ha (95 CI = 1192) during the post-nesting seasons. Mean home range size of nonbreeding adults was 290 ha (95 CI = 317) during the nesting seasons and 937 ha (95 CI = 846) during the post-nesting seasons. Breeding cranes used forested wetland (FW) (29.6%) and emergent wetland and other palustrine types (EWO) (27.6%) more than other habitat types during the nesting seasons; however, agriculture and grassland/herbaceous types (AgGH) (34.0%) and FW (33.0%) were used more during the post-nesting season. Nonbreeders used EWO (46.1%) and AgGH (25.1%) more during the nesting season; and EWO (41.8%) and FW (26.1%) during the post-nesting season. Cranes, overall, tended to strongly select EWO and FW during both nesting and post-nesting seasons each year, while strongly to avoiding AgGH.
Our results indicate that the breeding crane population in Ohio continues to grow steadily. Cranes are occupying smaller and more isolated pockets of wetland habitat throughout the northern part of the state and as far south as Pickaway County at Slate Run Metro Park, and Franklin and Fairfield Counties at Pickerington Ponds Metro Park.. These results suggest the need for continued management and enhancement of emergent wetlands at known occupied areas and potentially suitable unoccupied habitat areas. A protocol is necessary to establish a population viability analysis based on population vital rates such as survival, recruitment, fledge success, and mortality rates; and environmental factors such as suitable breeding habitat availability and land use changes (i.e. development, habitat restoration) to determine the minimum viable population of cranes in Ohio. More research is also necessary to better understand the potential that reproduction in Ohio and the flock of nonbreeding adults at Funk Bottoms WA are significant reservoirs of recruits into Ohio’s breeding population. Such information including considerations of socially acceptable population levels will contribute to determining when cranes can be delisted or down-listed as state-endangered in Ohio.