This project will generate new knowledge about the interactions between priority species and protected habitats in the Special Protection Area (SPA) of the Tagus estuary. To achieve this, an innovative high-precision system for the remote tracking of shorebirds will be implemented, both in the intertidal zone and supralittoral habitats. The system is based on recent technological developments that allow for the acquisition of GPS tracking data from medium and small birds, through the application of small tags with reduced weight and size that transmit this information to antennas placed at key points when in their proximity. Taking advantage of the already acquired knowledge about the ecology of these species, which feed in the intertidal zone during low tide and move to supralittoral refuges during high tide, the antennas collecting the tag information will be positioned in three important refuges of the SPA, representing three protected estuarine habitats: salt marsh, marsh lagoons, and salt pans. The antennas placed in these refuges, where the target birds of this study congregate during high tide, will thus be able to collect the GPS information recorded by the tags, attached to these species, previously captured and marked in these same locations. Obtaining this information is essential to eliminate critical gaps in current knowledge, particularly regarding the distance travelled by these birds between supralittoral refuges and the intertidal feeding sites. For example, it is known that this variable affects the use of more distant intertidal feeding areas. The innovative approach proposed here will allow for much more detailed information to be acquired for various species occupying different trophic niches in the estuarine habitat. This will make it possible to improve the conservation status of these species, for instance, by implementing management measures in specific refuges (such as those currently unavailable to accommodate the birds), enabling these birds to reach more distant intertidal areas in the SPA that are potentially underutilised due to the distance from the current available refuges. With this data, it will also be possible to quantify and map the connectivity between the protected habitats used as supralittoral refuges and intertidal feeding areas. In this way, potential threats and pressures in these habitats will be more easily anticipated and identified, such as the increasing activity of benthic invertebrate collection or the plans for the location of a commercial airport on the Montijo peninsula. Acquiring this knowledge will thus improve the conservation status of species and habitats protected under the Habitats and Birds Directives in this protected area.