Dendroica palmarum palmarum/hypochrysea
Medium warbler with olive-brown upperparts and yellow underparts streaked with brown. Cap is chestnut-brown. Western form is grayer overall and has white belly. It pumps its tail up and down more than any other warbler. Despite its name, it lives further north then most other warblers.
Western Palm Warbler (D.p. palmarum) in the first photo and Yellow Palm Warbler (D.p. hypochrysea) in the second.