migratory
adj.describing animals or people that move from one place to another at certain times of the year. You use this most often to talk about birds or fish that travel long distances to find food or better weather.
adj.relating to or characterised by seasonal movement from one region to another. Typically describes animals following cyclical patterns for breeding or feeding; can also describe human populations moving for seasonal work.
“Many migratory birds fly south for the winter.”
“The local wetlands are a vital stop for migratory species during their long journey across the continent.”
“Conservationists are concerned that rising temperatures may disrupt the migratory patterns of several whale species, forcing them to seek new feeding grounds in unfamiliar waters.”
Typically used attributively before a noun; often pairs with 'birds', 'species', or 'patterns'.
“Australia confirmed its first case of H5N1 in June in migratory seabirds.”
“The wider area is also an important passage and resting ground for migratory birds.” Israeli tanks make their way through the village of Zawtar al-Sharqiyah in southern Lebanon on 2 August.”
Borrowed from Latin migrātōrius or migrate + -ory.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.