| Term | Definition |
|---|---|
| Mandible | (noun) the exterior (outer), projecting part of a bird's mouth, composed of bone covered with a hard keratin shell. |
| Mangrove | (noun) a tree or shrub that grows in muddy, mainly tropical coastal swamps, and typically having numerous tangled roots above ground that form dense thickets. |
| Metabolic Rate | (noun) the amount of energy expended in a given period. |
| Molting | (verb) the replacement of all or part of the feathers. Since feathers cannot heal themselves when damaged, they have to be completely replaced. |
| Mutation | (noun) a change in the genes of a plant or animal that causes physical characteristics that are different from what is normal. |
