Unidentified metallic objects travelling at 500 mph or higher captured on film -- insects, optical illusions, or something more?

Please take note:

1) The incredible speed of the objects, measurably by the camera shutter speed
2) The absence of insect-like silhouettes, such as wings, a head or thorax
3) The metallic-like glare
4) The rapid appearance and disappearance of an object behind the cloud

In the video a "challenge" is mentioned. This challenge refers to someone else who has claimed these small metallic objects are flying nearly everywhere, but are unobservable due to their incredible speed, and who claims that anyone can turn their camera on, film the skies (preferably with witnesses) and then slow the footage down to spot the objects. If any of our readers would like to take up the challenge and link us to the results, we'd be interested in posting them.

Remember, however, we're seeking proof -- not sensationalism, so please be skeptical and logical in your pursuits. We look forward to hearing from you.