Delineating and identifying long-term changes in the whooping crane (Grus americana) migration corridor

Abstract

Defining and identifying changes to seasonal ranges of migratory species is required for effective conservation. Historic sightings of migrating whooping cranes (Grus americana) have served as sole source of information to define a migration corridor in the Great Plains of North America (i.e., Canadian Prairies and United States Great Plains) for this endangered species. We updated this effort using past opportunistic sightings from 1942–2016 (n = 5,055) and more recent (2010–2016) location data from 58 telemetered birds (n = 4,423) to delineate migration corridors that included 50%, 75%, and 95% core areas. All migration corridors were well defined and relatively compact, with the 95% core corridor averaging 294 km wide, although it varied approximately ±40% in width from 170 km in central Texas to 407 km at the international border of the United States and Canada. Based on historic sightings and telemetry locations, we detected easterly movements in locations over time, primarily due to locations west of the median shifting east. This shift occurred from northern Oklahoma to central Saskatchewan at an average rate of 1.2 km/year (0.3–2.8 km/year). Associated with this directional shift was a decrease in distance of locations from the median in the same region averaging -0.7 km/year (-0.3–-1.3 km/year), suggesting a modest narrowing of the migration corridor. Changes in the corridor over the past 8 decades suggest that agencies and organizations interested in recovery of this species may need to modify where conservation and recovery actions occur. Whooping cranes showed apparent plasticity in their migratory behavior, which likely has been necessary for persistence of a wetland-dependent species migrating through the drought-prone Great Plains. Behavioral flexibility will be useful for whooping cranes to continue recovery in a future of uncertain climate and land use changes throughout their annual range.

Differential changes in the onset of spring across US National Wildlife Refuges and North American migratory bird flyways

“…americana are in the Central flyway. There is evidence that the migration corridor in the US Great Plains region has narrowed and shifted eastward over the past few decades, possibly in response to habitat availability [ 60 ], but spring and fall migration timing was invariant over a 57-year period of observation (1943–1999) [ 61 ].…”

Temporospatial Shifts in Sandhill Crane Staging in the Central Platte River Valley in Response to Climatic variation and Habitat Change

“…This broad shift in climate could negatively impact basin wetlands and the water birds that depend on this habitat in the southern plains (Covich et al 1997, Reese andSkagen 2017). Pearse et al (2018) recently documented an eastern shift of about 1.2 km per year in the migratory corridor of the Whooping Crane over the last 8 decades. It is possible that eastward shifts in the distribution of Sandhill Cranes since the 1950s, which we continued to document in our research, are reflective not only of habitat change in the CPRV, but also of increasingly arid conditions in the western portion of the traditional Sandhill Crane migration corridor (Covich et al 1997, Reese andSkagen 2017).…”

The Lives, Lore, and Literature of Cranes: A Catechism for Crane Lovers

“…S. R. Derrickson (1980) and Pearse et al (2018Pearse et al ( , 2020 have supplemented his early records with more recent data.…”