Without cardinals, as well as many other birds, the planet would be overridden with insects. Also, they help disperse seeds to a wider range of land. The cardinal's habitat is a wide variety of places. Many prefer the edges of woods, and neighborhoods with a lot of vegetation. Crest on top of head raises when danger is sensed.
Males are the more aggressive of the two sexes.
The male attracts the female by a series of calls and by feeding sunflower seeds to her. In 1920, when the cardinal became Illinois' state bird, there were less cardinals in Illinois than there are currently. That shows that the cardinal's habitat has not been taken away, it has actually grown. Because of that, there are currently no real efforts to save the cardinal. This is unlike many other wetland birds who are losing their homes due to the destruction of the wetlands.