Journey North Hummingbirds

Why come north in the spring? What scientists think:
There is much more land for ruby-throated hummingbirds in their breeding range than in their wintering range. In fact, the breeding range is 25 million square miles compared to only 4 million square miles in the wintering range. Here's how that space can help hummingbirds survive and raise their young:

More Sunlight. As winter ends, more and more sunlight shines on the northern part of the earth. The sun is what brings all foodchains to life.
More Food. The sunlight warms the air and soil. Insects hatch and flowers bloom. Insects are the hummingbird's main food souce during the breeding season. Nectar is the fuel they need for migration.
More Space and Shelter. Once winter is gone, hummingbirds can use the space across the United States and Canada to build nests and raise young. Because hummingbirds can spread out, there is less competition for space here than on the wintering grounds.