A new study suggests the initial notion of how hummingbirds consumed nectar was wrong. Scientists previously believed hummingbird tongues utilized capillary action to take in floral nectar. The capillary action phenomenon means water flows through narrow areas and works against gravity. Scientists initially accepted the idea because the birds have grooves in their tongue that look similar to open cylinders, but it turns out their previous theory was wrong.
High-speed video captures hummingbird feeding
Researchers used high-speed videos to capture the birds in action and found that hummingbird tongues work as elastic micropumps, enabling the birds to feed at rapid speeds. Simple pumps like straws allow people to contort their cheeks and create a vacuum to suck up the liquid. Hummingbird tongues work in a similar way, minus the vacuum effect. The hummingbird stretches out its tongue to flatten it out and connect to the nectar surface; the tongue then reshapes to fill up with nectar.
In effort to pull in the nectar, the top of the tongue bends to store elastic energy and draws the nectar into the bird’s mouth. Researcher Alejandro Rico-Guevera elaborated that the fluid at the tip is driven into the grooves of the tongue, resulting in the collapsed section’s re-expansion. It is a fast technique that allows the hummingbird to drain anywhere from five to ten nectar drops within a 15-millisecond period.
The study took five years
The experiment setup took a total of five years to complete. Part of the test included constructing see-through “flowers” from tiny glass tubes and filling the tubes with artificial nectar. The scientists also had to set up high-speed cameras to capture the action. The experiment was conducted in multiple places in the United States and South America.
The new findings are representative of the largest data set on the science of hummingbird feeding. Scientists hope the data will offer more insight on the birds and how they obtain their food.