Date of this Version
Predation by ring-billed gulls (Larus delawarenis) has been identified as a significant threat to migrant steelhead and salmon (Oncorhynchus spp.) smolt in the Columbia and Snake Rivers. Bird predation appears highest immediately below hydroelectric facilities. Installation of overhead wire/cable exclusion systems over the tailrace area of 12 dams has been completed to reduce gull predation. Data collected from 1 of the facilities as well as observations from other dams indicate that overhead wire/cable exclusion systems are effective in reducing predation by gulls.