Which songbird turns the usual pattern of bird coloration upside-down by being lighter on top and darker below?

The male Bobolink in breeding plumage is black below, with a yellow head and extensive white on the wings and upperparts. Other songbirds are either uniform in coloration above and below, or are lighter below than above. This unusual pattern in male Bobolinks lasts only from very early spring until August, at which time they molt into plumage resembling the female. The black bill of the breeding male also changes to the paler color of the female’s bill at this time.