Dennis raised an interesting point regarding molt in the terns. He accurately stated that "Many gulls and some terns begin flight-feather molt while they are breeding, and it would be interesting to know if these terns proceeded with their normal molt schedule or molted much later than usual because of their late breeding." The Birds of North America account, the latest treatise on Caspian Terns (CATE), states that adult CATE may begin flight feather molt in some individuals on the breeding ground but, if they do, they arrest it before fall migration, and resume molting on the wintering ground. The extent to which molt and breeding may overlap in CATEs has not been studied.

During the past week, I captured 13 adult CATEs at the site in Tacoma. Interestingly, these birds which are currently attending their young in have either (1) arrested their flight feather molt after replacing two or three of their innermost primaries, or (2) are still growing P3. Thus, these birds appear to arrest their molt before P4 is dropped. It would be very interesting to examine adults attending young earlier in the summer (Early to late July) to see whether these birds begin molt that early. If they do not, this probably indicates that the CATEs currently in Tacoma were forced into overlapping molt and breeding because of caring for their young so late into the fall.

Chris Thompson
Research Scientist
WA. Dept. Fish and Wildlife