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Posted by John Boyd on 08:17:48 06/24/10
In Reply to: Re: Common Tern @ Cutler Wetland Jun 23 - 9:30am posted by Trey
Looks like first summer. It's not an adult. It takes them 3 years to become adults.
The way the plumages work is much like three-year gulls (e.g., Ring-billed) and there are seven plumages in all, which can be called juvenal, 1st winter, 1st summer, 2nd winter, 2nd summer, adult winter, adult summer. Or if you prefer basic/alternate style: juvenal, basic I, alternate I, basic II, alternate II, definitive basic, definitive alternate.
The 1st and 2nd summer plumages have names (portlandica and pikei). They are similar to the corresponding plumages of Arctic Tern. In the case of the Arctic tern, they were once thought to be separate species!
Kaufmann's Advanced Birding has information on this.
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