| Devil's Slide Rock (DSR), hosts a Common Murre (Uria aalge) colony which is close to San Francisco Bay and the Half Moon Bay airport. This colony has many challenges because of its proximity to potential disturbance sources. Historically, low-flying aircraft have posed a major threat to nesting seabirds on DSR. To assess the effect of timing and aircraft attributes, we constructed and ranked several multinomial log-linear models that included data from 2008 to 2014. Our top model included seven variables: year, reproductive timing, start time, aircraft type, aircraft category, altitude and distance; as well as the interactions between aircraft type and aircraft category, and between altitude and distance. The relative risk of disturbance varied from year to year, with 2010, 2011, 2013 and 2014 exhibiting a greater risk of disturbance than 2008. Disturbance was more likely during the pre-egg lay period and post-chick hatch period than during incubation. Helicopters were more likely to cause disturbance than fixed-wing aircraft. Displacement/flushing was more likely to occur at low altitudes and close distances. Our results support implementation of overflight regulations above DSR, similar to those implemented in other coastal areas. |