The game says that a glossy drecko consumes 100% mealwood/cycle. And it burns 2000 cal/cycle. BUT: when a critter eats it always raises its amount of calories to its maximum (10000cal) regardless of its current amount of calories. Even when it's starving (0 cal) and then it gets to eat 25% of a mealwood tree, the number of calories is increased by 10000 cal.
This way you can feed a hundred of critters just with a few trees.
Load my save. Take a look at the drecko calories number (it's 0, it's starving). The mealwood tree is about to reach 25%. When it happens the drecko eats it and it counts like 10000 cal (it should be just 500 cal)