Remsen, J.V. 1978 Yellow-billed Loon Gavia adamsii Feb.12 Monterey Bay boat trip, Monterey Co., Calif.: I seen within 1 mile of shore between Hopkins Marine Station and Lovers Point. I was going over loon identification with a beginner when the bird appeared conveniently next to a Common Loon just studied. It was the basic size and shape of a Common Loon but seemed larger, longer-billed, and thicker-necked. The bill was distinctly yellow, not pale grayish as in pale-billed Commons; the distal 1/4 of the upper mandible seemed particularly yellow; the culmen was clearly seen to be pale for at least the distal 1/2 (S.F. Bailey from the bridge was able to see that it was pale for its entire length); the rest of the bill was dull yellowish except for some dusky on the sides of the basal 1/3 of the upper mandible; the upper mandible was very straight except for a slight droop at the tip; there was a noticeable gap between the two mandibles when viewed from the side. The rest of the plumage did not appear to differ noticeably from Common Loon (perhaps closer study without pouring rain and wind would have yielded further differences), except that there was a dark smudge in the quiccular area which contrasted with a paler brown facial area. The bill was also held at a slightly upward angle. When flushed, the bird seemed very ponderous - very slow, labored wingbeats and large body. It dove and came up hundreds of yards from the original spot, repeated this 2-3 times, and finally eluded us completely; it was able to stay underwater for very long intervals. The bird was studied from as close as 40 yards (but more often 50-100 yds) for at least 3-4 minutes