Abstract
<jats:p>This technical note was developed by personnel from the US Army Engineer Research and Development Center–Environmental Laboratory (ERDC-EL) to describe the application of GPS/GSM (Global System for Mobile Communications) technology to wildlife studies to assess the effects of coastal engineering operations. GPS/GSM tags utilize cell tower transmissions to accurately locate animal positions in the landscape. While some satellite-based wildlife tags use Doppler technology, the GPS/GSM tags rely on GPS-based technology, which improves level position accuracy (e.g., ±30 m GPS/GSM tags versus ±300 m Doppler tags) in the landscape.* Doppler satellite tags break down distance accuracy into six location categories that range from ≤150 m to over 1,000 m, with a general average location accuracy of ≥300 m. The level of position accuracy with GPS/GSM tag technology permits researchers to determine if tagged birds are utilizing recently engineered coastal habitats (e.g., renourished beaches, dredged material islands, and restored wetlands), natural habitats, or minimally engineered coastal habitats. GPS/GSM tags could also be used to assess the frequency and seasonal changes of habitat use. Many coastal birds are known to breed on coastal dredged-material islands, often in response to coastal habitat loss wrought by dredging operations and other engineering actions (Soots and Landin 1978). In these same coastal areas, habitat degradation can occur through increased erosion and increased storm frequency and severity. The resulting habitat loss contributes to observed declines in coastal bird populations (Iglecia and Winn 2021; Newton 2004). These long-term population declines are not solely affecting coastal breeding species (Rosenberg et al. 2016). Habitat loss and population declines are also affecting many long-distance migrants that are seasonally transient and, thus, found along coastal habitats of the conterminous United States (Winn et al. 2013). The federally threatened Red Knot (Calidris canutus) is an example of a coastal transient species. Numerous other coastal birds currently experiencing population declines are potential candidates for future federal listing (Winn et al. 2013; Iglecia and Winn 2021). Interestingly, survey data suggested the Snowy Plover (Charadrius nivosus) avoids beaches that have been subjected to renourishment (Lott 2009; Lott and Fischer 2011), indicating that there may be variable, species-specific seasonal responses to coastal engineered habitats that remain poorly understood for many coastal birds. Therefore, there is a growing interest in determining the seasonal habitat needs of resident and migrant coastal birds and in approaches to beneficial uses of dredged material (BUDM) that could be used to design and construct year-round habitats (Guilfoyle et al. 2019, 2024).* However, much more research is required to determine the basic ecology, seasonal distribution, and seasonal habitat requirements of North American coastal birds to facilitate improved coastal habitat restoration and conservation. This technical note describes a pilot study in which 10 GPS/GSM tags were affixed to breeding Royal Terns (Thalasseus maximus; Figure 1) captured on South Island of the Hampton Roads Bridge-Tunnel in coastal Virginia. This study was part of a larger project to compile best management practices (Guilfoyle et al. 2019) and suggested management strategies† and was funded through the Ecosystem Management and Restoration Research Program (EMRRP). The Royal Tern was selected for this effort due to its relatively large size, which was suitable for a GPS/GSM tag, its known dependence on dredged-material islands for breeding, and its use of open beach habitats in the Southeastern United States and along the Gulf Coast during the wintering season.</jats:p>