The U.S. Postal Service introduced ten songbird stamps - these Forever® stamps are available in booklets of 20. Western Meadowlark, Mountain Bluebird, Western Tanager, Painted Bunting, Baltimore Oriole, Evening Grosbeak, Scarlet Tanager, Rose-breasted Grosbeak, American Goldfinch, & White-throated Sparrow.
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http://uspsstamps.com/blog/