How do birds help spread seeds in temperate forests?

In temperate forest ecology, birds facilitate seed dispersal through several primary methods, often referred to as ornithochory.12

• Ingestion and Excretion: Many plants produce conspicuous, fleshy fruits that attract birds like thrushes. These birds consume the fruit and later excrete or regurgitate the seeds, which remain undamaged and capable of germination. These fruits often feature bright colors (red or orange) and chemical defenses, such as tannins or acids, to ensure seeds are not eaten before they are mature.12
• Caching and Forgetting: Nut-eating birds, including nutcrackers, jays, and woodpeckers, cache seeds and nuts like acorns and hazelnuts for later consumption. Because these birds often forget the locations of their caches or drop seeds during transport, they effectively plant them in new areas.12
• External Transport: While less common, some seeds are transported externally. Sticky fruits may adhere to a bird's body, and small seeds can be carried in mud attached to the feet or feathers of waterfowl and terrestrial birds.12