What not to do while terraforming
My world is about where yours was during the Devonian period. If a breeding pair of ducks got loose back home, it would be a disaster.
With evolutionary advantages like bigness, feathers and warm blood, they would devour everything in their path like a web footed von neumann swarm.
My kind could defeat individual ducks. We wouldn't be able to protect the ecosystem. Doom would waddle across my planet and our only solace would be down pillows and very warm blankets.