Ian, OSU undergraduate assistant, viewing Common Murres on top of Colony Rock. (Credit Peter Pearsall)

After nearly a month of data collection with the OSU Common Murre monitoring team, the chance of an established colony on both Colony and Flat Top rocks is grim. It appears as though there is a trend that has become obvious to researcher and visitor of the offshore rocks alike. The continued harassment and predation by Bald Eagles has stressed the adult Common Murres, resulting in abandonment of nests, and has allowed  secondary predators such as Western Gulls and Common Ravens to feed on morsels of exposed eggs.  The opportunistic predators have been joined by others, including Turkey Vultures, and it appears as though Common Murre eggs have been labeled a relatively easy meal for local wildlife.
While there have been better days recently when multitudes of birds were found on both rocks with little to no evidence of disturbance, the continued presence of birds incubating eggs on the plots observed has eluded us. It seems as though eggs are averaging a lifespan of a couple of days, and the number of incubating adults are no more than 5 per plot on a given day. However, as stated before, smaller colonies on adjacent rocks seem to have prolonged presence of incubating adults and do not show clear signs of predator disturbance. Common Murres have also been spotted engaging in fish deliveries at lower colony rock and satellite rock. These are good signs that chicks may hatch soon.

Adult Bald Eagle with Common Murre in Talons being chased by Crow

Adult Bald Eagle with Common Murre in Talons being chased by Crow (Credit Peter Pearsall)

It will be interesting to see how Common Murres attempting to nest on Colony and Flat Top rock continue to deal with Bald Eagles and secondary predators. As we closely follow these birds, our hope is that the data gathered on disturbances will give us an insight into any possible patterns of attack, and the types of responses by the Common Murres.

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