Robust warbler found near the ground in thick vegetation. Yellow below with blue-gray head and olive back. Adult males show black chest patch. Females are paler gray on the head; immatures are more olive-toned with a yellowish throat. Breeds in brushy, weedy clearings within mixed or coniferous forest. Often favors raspberry thickets. Tends to stay hidden in low vegetation, so can be difficult to see. Listen for its rolling song, “churry churry churry chew.” Most similar to MacGillivray’s Warbler, but little range overlap, and Mourning has somewhat shorter tail and lacks bold white eye-arcs. Also frequently confused with Common Yellowthroat, especially in fall, but Mourning is larger, with heftier pinkish bill, and brighter yellow underparts.