Definition: Is a persistent and straightened-out movement effected by the animal's own locomotory exertions or by its active embarkation on a vehicle such as wind. Migration depends on some temporary inhibition of station-keeping responses, but promotes their eventual disinhibition and recurrence.
Definition: position of an organism in a food web. May be described verbally with descriptors including primary producer, herbivore or carnivore. If described numerically, 1 indicates a primary producer, 2 a herbivore, and so on up the food web.