Generally speaking, snoring is not a good thing. It destroys relationships and is associated with the damaging health effects of sleep apnea. It's not cute. Except when done by a hummingbird.

The BBC has provided us with this evidence:

It's hardly news that non-human animals snore, but the air passages of birds are different, and at least some sources claim only mammals snore.

However, it seems that what we are seeing here is not actually snoring, at least as we think of it. Snoring in mammals is caused by soft tissues relaxing during sleep and partially blocking the airways. That doesn't seem to be going on here.

Instead, this hummingbird is waking up from torpor, a sort of short-term hibernation required to prevent these tiny creatures from losing too much body heat to the surrounding air while asleep. One of the features of torpor is that the body cools down well below the temperatures at which other warm-blooded creatures sleep. Since hummingbirds have the highest metabolism of any vertebrate, saving energy in this way is important.

When hummingbirds are in torpor, they use so little oxygen that it is difficult to tell that they are breathing at all. While this saves a lot of energy overnight, it also means that waking up in the morning is even harder for them than for us, and they don't have coffee to help. Instead, they draw in huge amounts of oxygen (relative to their size) as their body starts to burn more fuel to raise their temperature to the point where they can properly wake up. The noise may be associated with this process of sucking in oxygen, although the physiological reason is not known and no studies have been done to confirm this.

This particular hummingbird is an amethyst-throated sunangel (Heliangelus amethysticollis) in a container used to measure the amount of oxygen while sleeping and as it wakes.

Some commentators are saying that the extended tongue and gasping rhythm is a sign of distress and the bird may be dying. However, when the video was first posted to YouTube three years ago (without the BBC's voice-over), the filmmaker claimed that once the bird woke up, it flew off apparently healthy and in search of its first feed of the day.