The White-Lined Sphinx Moth hovers over flowers, much like a bird, and can be found in a variety of habitats. It is very hairy so it could be mistaken as a small bird if not closely observed. See a White-Lined Sphinx Moth in flight while it visits flowers here:
The species is active both day and at night. They are attracted to lights and many of them may congregate together at a light source at night.
The caterpillar comes in a wide variety of colors. A more mature caterpillar is horned and can be black with yellow lines on the sides. The immature caterpillar is known to feed on a large variety of plants, but more mature ones tend to prefer evening primrose and roses.
This species is known to have population explosions in drier country. Its enormous range covers most of North America.