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Maryland Rock Industries Bald Eagle Entrapment Prevention Plan (Goose Bay)

Client: Maryland Rock Industries (MRI)

Location: Goose Bay, Potomac River, MD

Summary: Maryland Rock Industries (MRI) surface mines aggregate and sand at its Goose Bay Plant on the Potomac River. To process the rock and sand, MRI uses a recirculating system of ponds to settle the clay fines byproducts from the process water discharged by the wash plant. Between 2000 and 2004 a total of 20 bald eagles (Halieeatus leucocephalus) became entrapped in active clay fines ponds at the plant, despite the implementation of a bald eagle protection plan.

At the recommendation of the U.S. Fish and Wildlife Service (USFWS) and Maryland Department of Natural Resources (DNR), MRI hired an environmental consultant (Cardno ENTRIX) with extensive bald eagle experience to:

  • Assess baseline conditions of the local bald eagle population, current deterrents, the avian protection plan and mining operations.
  • Conduct a comprehensive (world-wide) review of bird deterrents to evaluate logistic feasibility, costs (start-up and maintenance), and potential effectiveness including habituation resistance.
  • Explore operational changes to the mining process to minimize the risk of eagle entrapments, and Prepare a Biological Assessment report of the results in support of a USFWS Section 7 Biological Opinion/Incidental Take Statement to authorize the future harm and harassment of bald eagles at the plant.

Field work and a review of MRI records showed that the plant primarily affected a large population of migratory, non-resident bald eagles that over-summer in the Chesapeake Bay Region. Summer concentrations of 15 to 30 eagles roosted each night in the surrounding forest edge and viewed the drying clay fines ponds as an open mud flat; birds became entrapped when they attempted to land to rest or bathe in the ponds. On some days, over 100 bald eagles frequented the site. Existing deterrents (cannons, Firefly II bird diverters and vinyl flagging on a Dacron line grid) were ineffective, perhaps because of behavioral habituation by eagles.

Cardno ENTRIX recommended design changes in the discharge of clay slurry into the initial treatment pond to prevent the premature formation of a mud flat and to limit pond dewatering until late fall - early winter, when the bald eagle population was lowest. During final pond drying when entrapments were most likely, a BirdDivert System (radar-activated cannons with human effigies) and a daily monitoring program would be deployed. The surrounding forest was placed under a conservation easement to protect this important bald eagle concentration area. These conservation measures were approved by the state and federal agencies. To date, no further entrapments of bald eagles have occurred at the Goose Bay Plant site.