Birds are regulators. So why they migrate? Bears are also the same so why they go to hibernation?

Hi,

Birds that nest in the Northern Hemisphere tend to migrate northward in the spring to take advantage of burgeoning insect populations, budding plants and an abundance of nesting locations. As winter approaches and the availability of insects and other food drops, the birds move south again.Escaping the cold is a motivating factor but many species, including hummingbirds, can withstand freezing temperatures as long as an adequate supply of food is available.

Bearstend to slow down during the winter, they are not true hibernators. Blackbears, Grizzlybearsand Brownbearsdo go into a deep sleep during the winter months, known as torpor.

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