11 August 2021

When hummingbirds sip nectar it can change their external body temperature. The change is visible in this thermal video of an Anna’s hummingbird by Gary Nunn.

After waiting four months I finally got my Pulsar Helion 2 XP50 Pro thermal scope! This thing is amazing—can’t wait to get out in the field with it. Anna’s Hummingbird taking a sip of jet fuel ? pic.twitter.com/iJsgmG0AvC

— Gary Nunn (@garybnunn) April 11, 2021

I’ve highlighted the bird’s temperature change with a slideshow of before and after snapshots.

• Before feeding: The bird’s head, body and throat are hot red. His shoulders are cool green.
• After feeding: The bird’s crop is full of cool nectar so his throat turns yellow. His shoulders warm up from green to yellow.

If we had a thermal sensor we could watch these Anna’s hummingbirds change color as they refuel.

(photo from Wikimedia Commons, embedded Tweet and YouTube; click the captions/logos to see the originals)