Aircraft and vessel disturbances to Common Murres Uria aalge at breeding colonies

• Main Authors: Nora A. Rojek, Michael W. Parker, Harry R. Carter, Gerard J. Mcchesney
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2007
• Subjects: Uria aalge; uria
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.541.4301; http://www.marineornithology.org/PDF/35_1/35_1_61-69.pdf

≤305 m above sea level. Helicopters tended to cause more disturbance than fixed-wing aircraft did, likely because of higher noise levels. At Castle–Hurricane, low aircraft flyovers occurred 49 % and 656 % more frequently than at Devil’s Slide Rock and Point Reyes respectively. Flyovers also resulted in flushing of adult murres more frequently at Castle–Hurricane (31 % of flyovers) and Point Reyes (25%) than at Devil’s Slide (4%). Boat disturbance to murres also was substantially higher at Castle–Hurricane than at the other two colonies, resulting in lost eggs and chicks. Most boat disturbances occurred when vessels approached within 50 m of active nesting areas and remained in the area for extended periods. The central California murre population declined extensively during the 1980s mainly because of mortality from gillnet fishing and oil spills. Although numbers increased at most colonies in the 1990s, the Castle–Hurricane Colony Complex only partly