Sparrow is a bird. All birds are warm-blooded so during colder weather, they have to spend more energy to maintain their body temperature. They have to consume more food, grow thicker feather or migrate to warmer region to survive the cold weather.
Sparrows do not migrate during winters. They adapt by building their nests near human habitats. Because human habitats usually have heat, the leaked heat keeps the sparrows' nests warm during cold weather.
Birds have a hard time in cold weather, because their body temperatures are higher than those of humans They provide warmth and insulation against colder temperatures. Many birds grow extra feathers in the months leading up to colder weather, so that they'll stay warmer when temperatures drop.
Increases because there's more food for the carnivores, as a result, the gradually the herbivores will decrease as the reach to a point they are no longer able to feed all the predators
