Tracking Non-breeding Habitat Use by Dunlin, Pectoral Sandpipers, and Other Migratory Shorebirds in the Mississippi Delta
USGS researchers and heir partners are capturing and banding birds that use man-made habitats to gather data on species occurrence, abundance, and energetic condition during autumn migration.
The Science Issue and Relevance: Shorebird populations have declined substantially in recent decades, and for migratory birds, loss and degradation of suitable stopover habitat is likely a major contributor to those declines. Conversion of natural wetlands in mid-continent North America has chiseled away at much of the historically available habitat, and this trend is particularly pronounced in the Lower Mississippi Alluvial Valley (LMAV). One potential tool for addressing the loss of such habitats is shallowly flooding (water depth less than 1 m) post-harvest agricultural fields to create temporary wetlands. Previous studies in this region and beyond have shown significant use of these man-made habitats by migratory shorebirds. Further understanding of habitat use within flooded agricultural sites and in the broader region requires knowledge of stopover duration, departure decisions, and basic stopover ecology for multiple shorebird species.
Methodology for Addressing the Issue: Capturing and banding birds that use man-made habitats allows us to gather data on species occurrence, abundance, and energetic condition during autumn migration. Capturing birds allows for assessment of energetic condition, collection of morphological measurements (e.g., wing length, mass), and the possibility to attach tracking devices. Radio transmitters and Bluetooth global positioning system (GPS) tags attached to selected species will provide information on stopover metrics and departure decisions that would be otherwise difficult to collect (e.g., habitat use at a landscape scale). On-site radio telemetry receivers are registered on the Motus Wildlife Tracking System network and record the identity of radio-tagged birds within the receiver’s detection radius. Individuals outfitted with radio tags can be detected within approximately 10–12 km of the receiving station when in flight or within a closer range when foraging or roosting on the ground. In addition to radio tags, some larger species are being tagged with Bluetooth GPS tags that collect location information when an individual is outside of the study area. GPS tagged birds have their locations logged at programed intervals that are stored on the device, and then data are downloaded when the birds fly within range of a Bluetooth receiving station.
Future Steps: This effort will further investigate the potential degree of support that artificial wetland habitats may provide to shorebird populations during the autumn and winter. Continuing to build this radio telemetry database will improve understanding of the degree to which individuals are using temporarily flooded agricultural habitats. Additionally, Bluetooth GPS tags attached to selected species (e.g., Wilson’s Snipe [Gallinago delicata], Dunlin [Calidris alpina]) will provide information on fine-scale use of created habitats, localized landscape-scale movements, and activity patterns. Such data would allow: 1) an understanding of movement and use of inland, non-breeding, and migratory habitats; and 2) the development of management practices that may increase and protect a robust mosaic of habitats necessary for supporting shorebird stopover in the LMAV. GPS data from this study can provide insight regarding use of flooded agricultural fields or alternative adjacent habitats for different activities, such as foraging or roosting. Additionally, results can directly inform management strategies in the LMAV by contributing to the quantification of the value of conservation practices, including water management for wildlife on agricultural lands.
Non-breeding Habitat Use of Flooded Agricultural Fields by Shorebirds within the Mississippi Delta
USGS researchers and heir partners are capturing and banding birds that use man-made habitats to gather data on species occurrence, abundance, and energetic condition during autumn migration.
The Science Issue and Relevance: Shorebird populations have declined substantially in recent decades, and for migratory birds, loss and degradation of suitable stopover habitat is likely a major contributor to those declines. Conversion of natural wetlands in mid-continent North America has chiseled away at much of the historically available habitat, and this trend is particularly pronounced in the Lower Mississippi Alluvial Valley (LMAV). One potential tool for addressing the loss of such habitats is shallowly flooding (water depth less than 1 m) post-harvest agricultural fields to create temporary wetlands. Previous studies in this region and beyond have shown significant use of these man-made habitats by migratory shorebirds. Further understanding of habitat use within flooded agricultural sites and in the broader region requires knowledge of stopover duration, departure decisions, and basic stopover ecology for multiple shorebird species.
Methodology for Addressing the Issue: Capturing and banding birds that use man-made habitats allows us to gather data on species occurrence, abundance, and energetic condition during autumn migration. Capturing birds allows for assessment of energetic condition, collection of morphological measurements (e.g., wing length, mass), and the possibility to attach tracking devices. Radio transmitters and Bluetooth global positioning system (GPS) tags attached to selected species will provide information on stopover metrics and departure decisions that would be otherwise difficult to collect (e.g., habitat use at a landscape scale). On-site radio telemetry receivers are registered on the Motus Wildlife Tracking System network and record the identity of radio-tagged birds within the receiver’s detection radius. Individuals outfitted with radio tags can be detected within approximately 10–12 km of the receiving station when in flight or within a closer range when foraging or roosting on the ground. In addition to radio tags, some larger species are being tagged with Bluetooth GPS tags that collect location information when an individual is outside of the study area. GPS tagged birds have their locations logged at programed intervals that are stored on the device, and then data are downloaded when the birds fly within range of a Bluetooth receiving station.
Future Steps: This effort will further investigate the potential degree of support that artificial wetland habitats may provide to shorebird populations during the autumn and winter. Continuing to build this radio telemetry database will improve understanding of the degree to which individuals are using temporarily flooded agricultural habitats. Additionally, Bluetooth GPS tags attached to selected species (e.g., Wilson’s Snipe [Gallinago delicata], Dunlin [Calidris alpina]) will provide information on fine-scale use of created habitats, localized landscape-scale movements, and activity patterns. Such data would allow: 1) an understanding of movement and use of inland, non-breeding, and migratory habitats; and 2) the development of management practices that may increase and protect a robust mosaic of habitats necessary for supporting shorebird stopover in the LMAV. GPS data from this study can provide insight regarding use of flooded agricultural fields or alternative adjacent habitats for different activities, such as foraging or roosting. Additionally, results can directly inform management strategies in the LMAV by contributing to the quantification of the value of conservation practices, including water management for wildlife on agricultural lands.