What a surprise i had today.here in Summit County, Colorado. While photoing finches on thistle flowers this small whirring insect came into view. I thought at first it was a hummingbird as its wings were moving at lightning speed but soon I saw that it was not. I took a lot of shots without having time to adjust any settings on my camera as i was afraid it would leave. Since coming inside to my PC I was able to research it and discovered what it is. Below a bit of information.
As soon as the sun sets during the warm part of the year from much of southern Canada down to Central America, large White-lined Sphinx (Hyles lineata) moths will emerge, and like nocturnal hummingbirds, these amazing fliers can be seen zooming around the garden and hovering before flowers as they sip nectar. Occasionally, these hummingbird-like moths can even be seen during the daytime, especially late in the season. These fast-flying moths are difficult to photograph in flight unless they are hovering before flowers and the light is good, but later in the evening, White-lined Sphinx moths can often be found resting near outside lights where they are much easier to observe and photograph. Often mistaken for a hummingbird, the White Lined Sphinx Moth is about 2 to 2 1/2 inches in length. It is extremely beautiful and its wings make a purring, or humming sound as the insect moves, using the same quick hover-and-dart technique that a hummingbird has!