Welcome back to the warblers!
From page 366-367 in The Warbler Guide:
The northern parula is very small and active. It has bright yellow throat and breast, and green back patch surrounded by blue. It has broken eye-arcs, which look prominent on its plain bluish face, black lores, and white wing bars. The northern parula is an acrobatic feeder, often hanging upside down. Its bill is brightly bicolored, unlike most other warblers. It is featured on the book cover of The Warbler Guide!
Warblers are among the most challenging birds to identify. They exhibit an array of seasonal plumages and have distinctive yet oft-confused calls and songs. The Warbler Guide enables you to quickly identify any of the 56 species of warblers in the United States and Canada. This groundbreaking guide features more than 1,000 stunning color photos, extensive species accounts with multiple viewing angles, and an entirely new system of vocalization analysis that helps you distinguish songs and calls.
The Warbler Guide revolutionizes birdwatching, making warbler identification easier than ever before. For more information, please see the author videos on the Princeton University Press website.