PS 21-199 - Distribution and migration chronology of a rapidly increasing population of Sandhill Cranes (Antigone canadensis)

Background/Question/Methods

At the beginning of the 19^th century Sandhill Crane (Antigone canadensis; ‘crane’) populations were largely extirpated from their range. Conservation actions have since enabled the species recovery. The migratory Eastern Population (EP) has experienced an average growth rate of 9.6% per year (1966-2007), and currently has >90,000 individuals. The EP breeding range is expanding eastward from its core in the Great Lakes region to the Canadian provinces of Ontario and Quebec. It is important to understand a species spatial distribution and chronology to make management decisions. However, little information exists for EP cranes breeding in Ontario and Quebec. Our objective is to determine the distribution, chronology, and important use areas of EP cranes that breed in Ontario and Quebec.

We deployed GPS-GSM transmitters on 84 adult EP cranes captured on fall stopover sites in Ontario and Quebec in 2019-2021. Transmitters collect a singular location every 30 minutes. We discarded locations with accuracy >10 meters. Locations were mapped using ArcGIS. We calculated kernel density estimates and used the 75% isopleth to delineate breeding, wintering, and stopover locations. Chronology was calculated as the arrival and departure dates between these areas.

Results/Conclusions

Cranes initiated fall migration late August to mid-September; the mean migration initiation date was 31 days earlier in 2021 than in 2020 (August 13^th and September 15^th respectively). Cranes used between one to four stopovers before arriving on wintering grounds in early-mid December in 2020 and 2021. Majority of cranes that travelled beyond southern Ontario during fall migration made at least one stop in Indiana at the south end of Lake Michigan. Cranes either traveled north of Lake Huron and East or West of Lake Michigan, or through southern Ontario. Cranes wintered within the Mississippi and Atlantic flyways and were widely distributed between Long Point, Ontario to Peninsular Florida. Spring migration pathways were similar to those used in the fall. Mean spring migration was initiated in late February in 2020 and 2021. Completion of spring migration was eight days earlier in 2020 than 2021 (April 18^th and May 1^st respectively). We document the annual distribution and chronology of cranes using Ontario and Quebec on the rapidly expanding eastern geographic edge of their range. These results are important for policy makers to make effective management decisions for this population as it continues to increase.