American yellow warbler

Wikipedia - American yellow warbler

To humans, these birds are quite beneficial. For one thing, in particular the young devour many pest insects during the breeding season. For another, the plumage and song of the breeding males have been described[3] as "lovely" and "musical", and they can help to generate revenue from ecotourism. No significant negative effects of American yellow and mangrove warblers on humans have been recorded.[3]

You can hear these birds sing at Yellow Warbler Sounds.