Despite their obvious avian origins, treshers also show indications of a complex, non-avian ancestry as well. Treshers are warm-blooded and suckle their hatchlings. During the four month long development cycle, embryo treshers are nourished by a small amount of milk secreted by the mother during incubation. In this way, a newborn tresher instinctively knows its parent at birth. Baby treshers are also aided at birth by a soft, fleshy snout for suckling; later the snout transforms into a hard beak.

While generally content to avoid interaction with humanoid life forms, treshers are extremely territorial with strongly developed social bonds. Treshers mate for life, and while generally unwilling to come into contact with strangers, will savagely defend their mates or their hunting grounds against any perceived trespass.

Treshers are vital to the ecology of Tinallis's oceans; they eat a large number of blue-ringed sea crabs, which, if allowed to overpopulate the area, could starve out many other forms of ocean life. However, the tresher's life cycle is fragile. High concentrations of heavy metals and manufactured chemicals can significantly weaken tresher egg shells and in polluted regions many treshers are stillborn. Treshers also have a very short lifespan - only about three to five years.

As a result, the Tinallis government has declared the tresher a protected species. However, because of their extremely attractive plumage and the desire for "exotic, gourmet" dishes, many treshers fall victim to poachers each year. It is also interesting to note that many biologists have violated Tinallis's laws, but with a different intent: they capture infant breeding pairs to be raised in a sheltered, clean environment in the hopes that treshers raised in captivity can breed. As the number of mating pairs in the wild slowly decreases, concerns are growing over the tresher's continued chances for survival.