Today, the HRBT complex supports the largest breeding seabird colony in all of Virginia. But did you know that the history of seabird conservation at this site actually dates back to the early 1980s?
Common terns and black skimmers begin nesting on South Island of the HRBT; both are Species of Greatest Conservation Need.
The Virginia Department of Transportation (VDOT) initiates management measures for nesting common terns and black skimmers under the direction of Ruth Beck, who was a faculty member at the College of William and Mary and studied and managed breeding seabirds on South island from 1983 until her death in 2015. Under Ruth’s steadfast guidance, VDOT annually consigned the west half of the island to the terns and skimmers during the breeding season where staff maintained suitable sandy nesting habitat free of predatory rats and vehicular traffic.
State-threatened gull-billed terns begin nesting on South Island along with several thousand pairs of common terns and approximately 100 pairs of black skimmers. Gull-billed tern pair numbers remained relatively low (fewer than 60 pairs) throughout their tenure on South Island.
Predatory laughing gulls begin nesting on South Island. Their numbers quickly increased from 18 pairs in 1999 to over 7,000 pairs in 2006. Laughing gulls were designated as Species of Greatest Conservation Need in 2015.
Large, predatory herring gulls and great black-backed gulls begin nesting on South Island. While the number of herring gull pairs exceeded 200 pairs in some years, the number of great-black-backed breeding pairs typically remained below 20 pairs.
As the number of laughing gull and herring gull breeding pairs continued to increase on South Island, so did their distribution; by 2003, gulls occupied nearly every nook and cranny on the island. This resulted in the displacement of common terns, gull-billed terns and black skimmers from the protected western half of South Island to unpaved surfaces adjacent to island roads and parking lots and I-64. This led to serious human safety concerns including accidents and numerous near-accidents in the tunnels caused by drivers trying to avoid striking gull and tern chicks that entered the interstate. The aggressive behavior of the seabirds also became a nuisance to VDOT employees, state police, contractors and other workers on the island. There was growing concern that increasing gull populations were reducing the reproductive success of terns and skimmers by way of displacement and depredation.
Additional avian management measures developed by a partnership consisting of Ruth Beck, VDOT, the DWR, and the USDA Wildlife Services, are implemented to: (1) contain flightless young by installing barriers around all nesting areas and (2) manage gull breeding activity on South island. This year also marks the arrival of six royal tern breeding pairs on the island. Over the next several years, their numbers grew to well over 3,000 pairs or over 80% of the Commonwealth’s royal tern breeding population. Royal terns are a Species of Greatest Conservation Need.
First pair of sandwich terns are observed nesting on South Island. Sandwich terns typically nest amongst royal terns and soon South Island became the species primary breeding site in the Commonwealth. Virginia and Maryland represents the northern extent of the sandwich tern breeding range; thus, their numbers fluctuate widely between years and has yet to exceed 400 breeding pairs in Virginia.
The HRBT expansion project, the governor’s most highly touted transportation initiative, gains approval and funding. The construction would effectively turn South Island into a major construction zone and thus no longer be suitable for breeding seabirds.
The DWR contracts with the Virginia Tech Shorebird Program (VT Team) to conduct seabird research on South Island during the final two breeding seasons before the start of the HRBT expansion project. The purpose of this work was to help assess the future effects of displacement from South Island on breeding seabird populations in Virginia and entailed marking as many tern and skimmer adults and chicks as possible with uniquely-coded field readable bands to:
- Allow for the subsequent tracking of individuals once they become permanently displaced from South Island;
- Establish survival rates and movement patterns through active re-sighting efforts throughout each species’ range;
- Quantify recruitment of marked birds to a newly constructed site or to other colonies within Virginia and beyond.
The VT Team also applied GPS transmitters on incubating Common Terns to gather information on within-breeding-season movements and to identify local foraging locations.
Nonlethal avian deterrence measures are implemented on South Island by the HRBT expansion construction company, and DWR provided more than 2 acres of temporary seabird nesting habitat on Ft. Wool and floating barges in the embayment between South Island and Ft. Wool as mandated by the Governor on February 14, 2020. These efforts prove to be incredibly successful when more than 12,000 adult seabirds utilize the newly created habitat for nesting. End-of-season nest counts estimate that the Ft. Wool/barge complex supported approximately:
- 5,250–6,011 royal tern nests
- 414 common tern nests
- 71 black skimmer nests
- 1 gull-billed tern nest
The DWR continued to use Ft.Wool and floating barges within the embayment to provide nesting habitat for the colony. Similar deterrence methods were employed at South Island to deter any birds from nesting there. End of season nest counts estimate that the Ft. Wool/barge complex supported approximately:
- 5,287–6,283 royal tern nests
- 663 common tern nests
- 139 black skimmer nests
- 15 gull-billed tern nests