Hanging out in the canopy: The upside-down life of hanging parrots

Hanging parrots of tropical southern Asia regularly hang upside down from branches in the canopy. Their ability to even sleep upside-down is unique among birds. But how on earth do you defecate while hanging upside down without soiling your beautiful green plumage?

Every now and then, when reading scientific literature, I come across little snippets of information that just blow me away. This may be just a little side note or a footnote, but it can make my nature-loving scientist heart leap for joy. This is exactly what happened to me earlier this year, when I read this sentence in a paper about climbing parrots¹:

Moreover, parrots have extensive documented histories of […] adopting suspensory behaviors in other contexts (e.g. hanging parrots, who are unique among avians in choosing to sleep while suspended upside-down in a similar manner to roosting bats).²

I couldn’t stop smiling after reading this. “There are parrots sleeping while hanging upside down? This is amazing, everybody should know about this!”

To my surprise, I didn’t find much research about this unique behavior. However, here I’ll give you a brief overview of what I learned about the upside-down life of parrots hanging out in the canopy.

There are 15 described species of hanging parrots (Genus Loriculus), all of them endemic to the tropical regions of southern Asia (and thus sadly all of them threatened by habitat loss due to deforestation). Their ability to sleep upside down is unique among birds and gave them the name “Fledermauspapageien” (“Bat parrots”) in my native language (German).

Why hanging upside down? Sleeping in a hanging position improves their camouflage (with their green plumage and hanging posture, they resemble leaves) and helps them avoid predation while sleeping.

In 1968, Francine G. Buckley, a researcher from Cornell University, published a research paper about the behavior of two species of hanging parrots, the Blue-crowned hanging parrot and the Vernal hanging parrot. She reported that these birds not only sleep and rest while hanging upside down. They also engage in many other activities in that position, such as rain-bathing, feeding, preening, scratching, stretching, climbing, and fighting.

Hanging upside down comes with challenges that are not immediately obvious. Regularly switching to a hanging position requires adjustments to the circulatory system and the leg musculature. Due to these difficulties, very young and sick birds do not engage in a hanging position.

Another important challenge related to the upside-down life of hanging parrots is… defecation. As a hanging parrot, how do you relieve yourself while hanging upside down without soiling your beautiful green plumage? Buckley described how these birds manage to do that: To defecate, they hang by only one foot and swing their body around to a 45-degree angle relative to the perch. Their tail is slightly raised over the back to get it out of the way. Then, they eject the feces away from their body using a strong contraction of the cloacal muscles. Simple, but effective!

Hanging around in the canopy also has a social and almost romantic aspect to it. During courtship, males offer food to the female of their choice. And guess what? If the female accepts the food, the male is allowed to hang around closer to her.

• Parrots
• Hanging parrots