This mesmeric video was recorded by scientists in a Peruvian lab who were studying the sleeping patterns of hummingbirds.
Hummingbird have an exhausting life – in order to “hover” they have to beta their wings between twelve and eighty times per second. To achieve this they don’t bother having insulating feathers like other birds,which mean sat night they can get very cold. To overcome the night time shivers hummingbirds deliberately lower there internal temperature and slip into a kind of a temporary hibernation.
In the mornings it take them about 20 minutes to fully awaken from this deep sleep – they gradually take in more oxygen which increases their body temp. Its this gasping for oxygen that causes the “snoring” sound.