From car windshields to cats, birds around the world face plenty of mortal threats. But as IFLScience reports, avians in Puerto Rico have particularly unique forest foes that until recently were unknown to science. Deep in the island's jungles, researchers have discovered two new species of "bird-catcher" trees, bearing ripe, sticky fruits that—yes—can quite literally trap and kill birds.

As recently described in the journal Phytokeys, the trees—which are members of the genus Pisonia—produce fruits with viscous skins covered in tiny hooks. If a bird perches on the tree, a piece of fruit can stick to its body; when the bird flies off, it takes the fruit with it, potentially dispersing it somewhere else on the island. But if the fruits become too tightly affixed to birds, they can trap and kill their tiny transporters. Their tiny bones sometimes litter the trees' swollen roots, which wrap over rocks and are said to look like elephant feet. 

The trees' discovery has resulted in the long-due recognition of two overlooked female figures in Puerto Rico. The trees were given the names Pisonia horneae and Pisonia roqueae to celebrate the scientific contributions of Frances W. Horne (1873–1967), an American illustrator whose vibrant watercolors depicted hundreds of Puerto Rican plants; and Ana Roqué de Duprey (1853–1933), a Puerto Rican academic, writer, suffragist, and amateur ethnobotanist.

"It only seemed natural to name the two new species after these two extraordinary women who spent decades on large educational projects aimed to divulge botanical knowledge in Puerto Rico," study co-author Jorge C. Trejo-Torres said in a statement. "Just like the two large trees remained unrecognized by science until now, the enormous efforts of these two women, who dedicated part of their lives to botanical work, remained largely unrecognized by the community."

The infructescences of Pisonia roqueaeJorge C. Trejo-Torres

The 'elephant foot' trunk of Pisonia roqueae.Jorge C. Trejo-Torres

[h/t IFLScience]