Stage-specific shifts in habitat selection by Black-tailed Godwits under saltpans’ water-level management during northward migration in Bohai Bay

Tidal fluctuations influence shorebird use of tidal flats and saltpans in coastal wetlands. Saltpans also undergo periodic water-level management, resulting in temporally varying habitat conditions during shorebird migration. However, how shorebirds shift their habitat use between tidal flats and saltpans across successive migration stages under different tidal conditions remains poorly understood. We used Kernel Density Estimation and Manly’s selectivity index, combined with GPS tracking data from 2017 to 2026 and tidal records, to quantify habitat selection patterns of the near-threatened Black-tailed Godwit ( Limosa limosa ) on saltpans along the Tianjin coast of Bohai Bay across four migration–management periods and two tidal conditions. Habitat selection differed significantly among the four migration–management periods for both tidal flats and saltpans under high tides (χ 2 = 23.28 and 23.54, respectively; both p < 0.001) and low tides (χ 2 = 19.82 and 15.47, respectively; p < 0.001 and p = 0.001). Saltpan selection increased markedly during the later stages, with selection shifting from tidal flats toward saltpans during Phase III–IV under both tidal conditions. At the individual level, core-use centroids showed a pronounced redistribution toward saltpans during Phase III–IV. At the population level, spatial hotspots progressively shifted from tidal flat areas and their adjacent zones toward saltpans (the Hangu Saltworks No. 1 Branch), with the most extensive concentration of shared use occurring during the Phase III. Our findings highlight clear stage-specific shifts in habitat selection and spatial use by Black-tailed Godwits during northward migration. These findings support phase-specific conservation management that maintains suitable shallow-water and exposed-substrate habitats in saltpan hotspots during periods of increased saltpan use. These findings may also provide a reference for phase-specific management in other saltpan systems, while specific management practices should be adjusted according to local migration progression, tidal patterns, and saltpan management schedules.