Treshers, sizable seabirds, built their nests upon the coastal cliffs of the world known as Tinallis. Their diet primarily consisted of fish and other aquatic life, with a particular preference for the blue-ringed sea crab.
Despite possessing a generally avian physiological structure, they exhibited several traits characteristic of mammals. Notably, female treshers nourished their offspring with milk. For the initial four months of their lives, tresher chicks possessed soft, fleshy mouths suited for suckling from their mothers. As they matured, these mouths evolved into hard beaks. Unlike the majority of avian species, they possessed beaks equipped with teeth and bony ridges embedded within their tail feathers.
Though awkward and clumsy when on land, treshers demonstrated remarkable grace and speed during flight. Their exceptionally sharp eyesight enabled them to detect prey from considerable altitudes above the ocean's surface, allowing them to dive with exceptional precision and accuracy. They were capable of reaching speeds of up to 160 kilometers per hour during a dive, halting just above the surface to seize their prey with their talons.
Regrettably, treshers exhibited a vulnerability to pollution. The presence of heavy metals or industrial chemicals in their environment weakened the structural integrity of their eggshells, resulting in a high incidence of stillbirths among tresher chicks in polluted regions.
Treshers formed lifelong pair bonds and exhibited fierce protectiveness towards their nests, offspring, and mates. While they generally avoided interaction with humanoids, treshers were known to attack intruders using their beaks, tails, or talons. A fully grown tresher was capable of seizing a creature of humanoid size and carrying it aloft for a distance of at least one hundred meters. Even tresher chicks possessed a formidable bite.
Treshers also became the hunted prey of hunters, owing to the high demand for tresher meat among certain gourmets across the galaxy, and their vibrant plumage was highly valued. The potential extinction of treshers would have had catastrophic consequences for the ecological balance of Tinallis, as the population of blue-ringed sea crabs was primarily regulated by predation from treshers. In response, the Tinallian government designated treshers as a protected species, thereby criminalizing the hunting of treshers or the removal of eggs or live specimens. Despite this legal protection, tresher poaching persisted. Indeed, some biologists from other worlds violated the law in order to acquire chicks or eggs for captive breeding programs aimed at establishing a secure population. One biologist residing on Deminol offered 10,000 credits for a single tresher egg. The hunter she employed, Fendel Ramison, ultimately failed in his mission.