Harlequin Duck

I'm on vacation for the rest of the year and decided to start the time off by renting a 600mm f/4.0 lens and a 1.7x teleconverter for the weekend. I've rented the 400mm f/2.8 a couple times in the past and have been wanting to try the 600mm. Since waterfowl are the main attraction these days and many are too far out on the water for my 300mm to reach, I thought now would be a good time to give it a try.
Pro Photo in Portland rents either for $80 a day. However, if you rent over the weekend, you can pick it up on Thursday after 3:30 and don't have to bring it back until Monday morning at 10:30 for the same price. Pretty good deal I think since buying these lenses would set you back somewhere in the neighborhood of $8000+.
I started out yesterday with a trip to the coast. I thought since I have all this glass, I'd try Boiler Bay since I read about all the sightings on OBOL. Unfortunately, I didn't have much luck. Not sure if was because the birds were all way off the coast because of the good weather or that they typically are always way off the coast and even with all this camera glass, it is no match for a good viewing scope.
So after a couple of hours of frustration, I decided to move to Yaquina Head Outstanding Natural Area. I was there last summer and it was alive with birds. A 600mm lens would have been great to have during that trip. I knew that it wouldn't be like that now during the winter, but I thought I'd give it a try anyway.
Turned out I was right, Colony Rock was mostly barren except for a gull here and there. But that's were the 600mm with 1.7x teleconverter came into play. I started scanning the rock and surrounding ocean with both my camera and binoculars and eventually started finding birds. There were quite a few Black Turnstones, Surfbirds (I think) and Black Oystercatchers on the rock. In the water I saw Western Grebes, Common Loons, Surf Scoters, Black Scoters, various Cormorants and Harlequin Ducks. There were also other birds further out that I haven't been able to identify because of the distance. With the exception of the Oystercatchers, I probably would not have been able to identify any of these birds with either my binoculars or 300mm lens.
The Harlequin Ducks, in the images above, where out quite a ways. In the lower image they were actually on the sea side of Colony Rock. In the upper image they were to the south also out beyond the rocks.