Abstract:

The Texas coast supports 130,000 waterbirds annually on a network of colony islands from Galveston to the mouth of the Rio Grande. Each year, millions of dollars are spent by organizations and agencies to create, manage, and restore colony islands on the Texas coast, but without guidance on which islands provide the greatest benefit to birds, funds and management effort may not be as effective as possible. Stakeholders and land managers need a tool to guide decisions on which islands to restore. To this end, we collected telemetry data for 20 black skimmers (Rhynchops niger) between 2019 to 2023 by fitting solar GPS-GSM tracking devices (model OrniTrack 9, 10, or 15, Ornitela, UAB) that constitute < 2% of a bird’s body mass. Movement data enables us to 1) delineate foraging ranges around colonies, 2) estimate relative numbers of nests each bay system can support, and 3) estimate the probability of use for different habitats within their foraging ranges. These data will ultimately become one of many inputs to support a GIS-based model that prioritizes colony islands for management and rehabilitation on the Texas coast based on their greatest potential for birds. The suite of related datasets include tracking for black skimmers (2019-2023: HI.x960.000:0003, https://doi.org/10.7266/7kxf3hqd, Caspian tern (2022-2023: HI.x960.000:0004, https://doi.org/10.7266/gqtgaw3g; 2024: HI.x960.000:0008, https://doi.org/10.7266/jvpaa0ys), tricolored heron (2023: HI.x960.000:0005, https://doi.org/10.7266/3y4qnaax; 2024: HI.x960.000:0006, https://doi.org/10.7266/pr3pj20d), and great egrets (2023: HI.x960.000:0002, https://doi.org/10.7266/manamsa7; 2024: HI.x960.000:0009, https://doi.org/10.7266/8gpn11g2).

Suggested Citation:

Gawlik, Dale, David Newstead, Jordan Giese, David Essian, and Bart Ballard. 2025. Movement data for the Colony Island Network Design and Implementation (CINDI) project to recover waterbirds in the Gulf of Mexico: black skimmer (Rhynchops niger), 2019-2023. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/7kxf3hqd

Purpose:

The purpose of this dataset is to 1) delineate foraging ranges of black skimmers (Rhynchops niger) around colonies, 2) estimate relative numbers of nests each bay system can support, and 3) estimate the probability of use for different habitats within their foraging ranges. These data are important as mobile species like waterbirds often get most of their food from a small part of their foraging range, and not necessarily the part close to the nest. Tracking data to identify the location and type of important foraging habitat for each species enables us to estimate the number of nesting pairs a bay system can support, which affects the prioritization of particular islands.

Data Parameters and Units:

Logger ID, Year (YYYY), Month (MM), Day (DD), Hour (UTC, HH), Minute (MM), Second (S), Latitude (WGS84, decimal degrees), Longitude (WGS84, decimal degrees), Speed, Date_2 (Microsoft format, enum), Position Dilution of Precision, Horizontal Dilution of Precision, Vertical Dilution of Precision, Heading, No.Gps...Light, Additive.Vincentys.Distance (km), Travel.Speed (km/hr), Raw.latitude2, Decision.voltage3, Millisecond, Deployment Date (MM/DD/YYYY), timestamp (MM/DD/YYYY HH:MM), Distance (km).

Methods:

This dataset used telemetered birds associated with colonies in the study area to identify distances that focal species will fly to access foraging habitat and the location of core foraging areas. Between 2019 and 2023, 20 black skimmers (Rhynchops niger) were captured in and around target colonies and fitted with solar GPS-GSM tracking devices (model OrniTrack 9, 10, or 15, Ornitela, UAB) that constitute < 2% of a bird’s body mass. Transmitters were attached to birds via a backpack or leg-loop harness using a 4 mm Teflon-elastic ribbon. The devices are solar rechargeable with a theoretical life of two years. Devices transferred data via the cell phone network and stored data onboard when in areas where suitable connections could not be made. We programmed tracking devices to collect location data once every hour.

Instruments:

Solar GPS-GSM tracking devices (model OrniTrack 9, 10, or 15, Ornitela, UAB)

Individual Files: