Fiddler ray snouts are translucent. The fiddler rays are also distinguished from other guitarfishes in that the anterior nasal flaps of their nostrils are expanded backwards and fused together into a nasal curtain that reaches the mouth. Fiddler rays feed on bottoms shellfish, crabs, and worms, which they crush between their jaws. The eastern fiddler ray is known to scavenge from fish traps. Like other guitarfishes, fiddler rays are ovoviviparous. The egg capsules of the southern fiddler ray are reported to be golden in colour, containing three embryos each. It gives birth to litters of four to six young per breeding cycle.
White-browed hermit the very similar Reddish Hermit ("Phaethornis ruber") which generally occurs at lower elevations, and identification criteria between the two species is still not well known. White-browed Hermit may be slightly paler with more bronze coloration in the tail. The range extends along the base of the Andes from central Peru south to central Bolivia, in an elevational band from 350 m to 1400 m. The species is generally encountered most often within forest interior, although individuals occasionally forage along forest edge. Like most hummingbirds, it feeds mostly on nectar from a variety of flowers, but also consumes some small insects.