Common Terns, minor miscellanea

Every year, a small to rarely moderate number of Common Terns turn up at a few favored sites on San Diego Bay starting in July. Typical locations include Emory Cove, Salt Works, and J Street. This year they have been in short supply so far, with perhaps only one one-year-old bird hanging around. I saw one this morning (Monday) at Emory Cove, and Matt has had one (same?) in recent days inside the Salt Works. Typically a majority of these summer birds are one-year-olds, but a small number of second-cycles and adults are found as well. They are most often associated with loafing flocks of Elegant Terns. Now, the problem arises every year where at least a few of the sightings are based solely on the presence of a dark carpal bar, and it seems that all other field characters are ignored. Unfortunately, many juvenile terns of other species have dark carpal bars, as do some worn Forster’s Terns–although such bars do not tend to be as sharp and boldly blackish as they are in Commons. Anyway, Common ID’s should ALSO be based on such items as bill color and size, head pattern, overall size of the bird, etc. etc.

In other, minor news, a Ring-necked Duck and American Wigeon continue at Sweetwater Reservoir, where also a notable post-breeding increase in molting, REAL Mallards; and a Ring-billed Gull continues at Eastlake. Returning tundra-breeding shorebird numbers seem slightly delayed, but the past couple days there have been ca. 2500 Western Sandpipers at the Salt Works, where also the first juvenile Willets of the season arrived yesterday.

–Paul Lehman, San Diego