"Falconers have long known that various raptors, especially accipiters and eagles, exude a clear fluid from their nares while eating. ... As the hawk ate his prey, the small droplets of fluid that collected on our gloves had a strong salty taste."
- Nasal Salt Secretion in Falconiform Birds, by Tom J. Cade and Lewis Greenwald
How did they find out the clear liquid from the hawk's nostrils tasted salty? I wondered as I read the paper's abstract. Did they miss a professor's warning to never consume a science experiment? Then again, I had only found this paper because I had just discovered that salty fact firsthand.
Just a few minutes before a Google search led me to this paper, I sat in the office with Carson the Red-tailed Hawk on my glove. She swallowed a tasty mouse tidbit and watched the office alertly. There was a shiny black line along her beak where a liquid ran from her nares to the tip of her hooked beak where it gathered in a drop. With a flick of her beak, she sent a wet spray on my face. This time I happened to have my mouth open just enough to taste a salty droplet. I sputtered and wiped my face with my sleeve.
I often joke that Carson has a "runny nose," just like me through most of the winter. Her nasal secretions can serve the same purpose as in humans: to keep nasal passages moist and clear of debris. I had also heard from other raptor handlers that bird nares might drip (or even sneeze) when they are excited. Many hawks will initiate secretions when feeding, and some birds seem to start after exposure to the sun. But what is the purpose and why would it be so salty?
The answer seems to be largely unknown. Because of their high-protein diet, they may need this nasal gland to excrete excess salt. But many raptors with similar diets do not have this feature while unrelated birds do. American Kestrels and owls have minimal nasal secretions, but omnivorous ostriches tend to drip.
Is the drip due to diet, mood, or sun exposure? I may never know. Whatever the purpose, I now learned my lesson to keep my mouth closed when I am within spitting distance of Carson!
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