Grand-Case Bay; How do Brown Pelicans survive their death-defying dives? 

How do brown pelicans survive their death-defying dives?

Brown pelicans hit the water at breakneck speed when they catch fish. Performing such dangerous plunges requires technique, equipment and 30 million years of practice!

Their vision is excellent in air but very poor under water, so they must target their prey carefully before impact, all the while being cautious of not going blind upon hitting the surface. To do so, brown pelicans have special sheets called nictitating membranes, that slide over the eyes like automatic swim goggles.

Powerful muscles also tense around the spine keeping the bird from breaking its neck, and its sword-shaped bill slices through the surface at high speed with almost no drag.

These pelicans are surface hunters not deep divers so when they hit the water they also hit the brakes! Birds slow right down thanks to a built-in “life vest”; a special network of air sacks under the skin, around their neck and belly and even in their bones. As soon as the pelican hits the water it takes a deep breath of air. Pneumatic foramina; tiny caverns inside the bones rush the air inside, cushion the impact and makes them float.

Another flotation device is the gular pouch, which is made of stretchy skin reinforced with collagen fibres that prevent it from breaking.

These clever birds also have an extra flexible jaw that opens sideways not just up and down, and a super efficient “fishing net” with a pouch that can hold much more than their belly can!

Sources: How do pelicans survive their death-defying dives? (3m21s, vid.), Deep Look S4E9, KQED, online on 07/24/2024 on pbs.org