used to be as common as robins. They were lauded in poems and songs. But then, in the mid 20th century a combination of very bad winters and industrialization caused the bluebird to decline in numbers, almost to extinction. Thanks to conservation efforts, including the establishment of numerous bluebird trails, bluebirds are once again becoming common in the United States. Bluebirds and beloved because of their familial habits. The male bluebird will feed the female who will feed the babies while they are nestlings. The male may even recruit some of his older children from the first nesting of the season to help out. If something happens to the male, then the female takes over. Other females help her. It is not uncommon to see three or more birds taking food to a single nest.
Juncos - snow birds - are the most common birds at bird feeders. They spend summers in Northern Canada and migrate to the United States for winter. They don't usually take food directly from feeders, however. Rather they forage food from the ground, picking up seeds that have fallen out of the feeder.
Robins are true generalists and have adapted well to living around humans. They inhabit any land with an abundant supply of fruits, berries, and in the breeding seaons, worms. Their adaptability has made robins far more prevalent today than before white people moved to the New World.
Crows and loud and noisy birds, but some of the most intelligent of the bird species. They are able to use tools, and can go through at least a two step process to use a tool to get to a tool that they can then use to get to food.