That prompted conservationists to create thousands of acres of jack pine habitat specifically for the warbler and even take the fight to parasitic cowbirds known to take over warbler nests.

Sitting on the highest branch on a sunny July morning in a jack pine barrens in Adams County, a male Kirtland's warbler sang its love song. Need a break? Play the USA TODAY Daily Crossword Puzzle.

Despite its recovery from the endangered species list, the tiny Kirtland’s warbler still needs some help from humans. Volunteers are needed this spring to help plant pine trees for the still ...