The medium-size Golden Parakeet is almost entirely yellow—a rich, bright color, like a jar of French mustard—save for deep green feathers along the tips of its wings. The indigenous people of the Amazon call it an ararajuba, or small yellow macaw. The endemic Brazilian Amazon birds are known for caring so much for their young that they enlist fellow birds to help raise each chick. Braulio Dias, an ecologist at the University of Brasília, a former head of the United Nations Convention on Biodiversity, and the current chairman of BirdLife International, worries they'll need more help than that to survive this year in the Amazon. This season, thousands of fires have been burning up the Amazon in Brazil and Bolivia, including in the habitat of the Golden Parakeet. It’s a species whose habitat is already threatened by deforestation, says Dias, and fires add to the pressure. Other vulnerable species that share similar habitat, according to a national action plan from...