Trends in Winter Landcover Suitability for Sandhill Cranes Wintering in the Central Valley of California

The Central Valley of California provides critical wintering habitat for Sandhill Cranes (Grus canadensis), which rely on wetlands, grasslands, and grain crops to meet their energetic needs. However, temporary row crops that support Sandhill Cranes and other wintering birds are ostensibly being replaced by permanent woody crops, which offer little value for wetland and grassland-dependent species. To better understand how landcover changes may be affecting habitat availability for these wintering cranes, we analyzed landcover trends within priority crane wintering areas from 2008 to 2023. We employed a mixed-methods approach that allowed us to describe both linear and non-linear trends over time and across regions. Our findings indicate a significant decline in landcover types suitable as crane habitat over the 16-year period (τ = -0.90, p < 0.001), with an average annual loss rate of approximately -1.15 ± 0.21% (B ± 95% CI). The best-fit trendline showed that habitat suitability in priority wintering areas decreased from over 81% in 2008 to under 65% in 2023. Specifically, grasslands, rice fields, and alfalfa acreage declined across priority wintering areas, while woody landcover —including orchards, vineyards, and riparian forest breaks— increased significantly (τ = -0.88, p < 0.001; B = 1.14 ± 0.20%). These landscape-level changes may constrain the regional carrying capacity for Sandhill Cranes and reduce their overall resilience.