By Julie Etra—

Brown pelicans (Pelecanus occidentalis) are a common and delightful sight along Mexico’s Costa Chica. I never tire of watching them swoop and glide effortlessly along the coastline, skimming just above the waves as if gravity barely applies to them.
Brown Pelican Basics.

Taxonomy
Based on fossil records, they have been around for at least 30 million years but have remained morphologically and physiologically unchanged. Their seemingly bulky body is perfectly suited to the coastal ecosystems in which they reside, including their feeding habits. Although references vary there are five to seven species of pelican worldwide. The Oaxacan coast is unusual because two subspecies may be found here: the California brown pelican (P. o. californicus) and the Eastern brown pelican (P. o. carolinensis), although most of the birds seen locally are believed to be P. o. carolinensis. Their differences are subtle, so next time you see one pay attention. They rarely venture more than 20 miles out to sea or far inland and are non-migratory.

They are relatively uniform in appearance, with of course the large white pelican being the exception (this is a fresh or brackish water species). They typically live 15-30 years in the wild although mortality is high in the first few years of life and are sexually mature at three- five years of age. Populations have rebounded dramatically from the brink of near extinction due to the pesticide DDT, which weakened the shells of their eggs, and was banned in the United States in 1972. Today their numbers are estimated to exceed 370,000.

Feeding
Brown pelicans primarily eat fish, particularly sardines and herrings but also an occasional crustacean, egg, or amphibian. When I head out to snorkel at Playa La Entrega and see circling pelicans and cormorants, I know there is most likely a huge school of Pacific herrings, known locally as sardinas (such a beautiful sight to see). They fish by plunge-diving headfirst, with their wings tucked behind their backs, and stunning their prey before they are scooped up. Their big gular pouch is highly elastic and is perfectly suited for fishing. It can hold up to three gallons of water, which it drains before swallowing its prey. The pouch is also highly effective for regulating heat given its elasticity and large surface area.

Reproduction
Nesting ranges from Sinaloa south through Nayarit, Jalisco, and Guerrero, and finally the coastal shores of Oaxaca. They are gregarious birds and nest in colonies.
Nests are a messy but elaborate affair when built in thickets, such as dense stands of mangroves, a platform made of sticks and branches, or a simple version directly on the ground. Nesting typically occurs late fall through early June and is accomplished mostly by the females. Clutch sizes vary but typically consist of two or three oval, chalky white eggs, with both the male and the female sharing incubation and rearing responsibilities. Eggs are incubated under their large, webbed feet for 28- 30 days. The parents feed the young by regurgitating their partially digested catch into the awaiting, gaping beaks. At about 63 days they fledge from the nest and form small groups known as pods. I have never seen a pelican nest, and much to my surprise neither has the expert local guide Cornelio Ramos.

Flight
This to me is the most fascinating aspect of brown pelican behavior. I see them flying in V formations, in single file, and sometimes alone, often skimming just inches above the water’s surface. What appears effortless is actually a remarkable combination of aerodynamic strategies that allow these large birds to travel long distances while conserving energy.

Wave-Slope Soaring
Brown pelicans take advantage of wind generated by ocean waves. As wind pushes up against the face of a wave, it creates a small updraft. Pelicans position themselves in this sweet spot and essentially ride the moving air, reducing the effort required to stay aloft. This technique, known as wave-slope soaring, can reduce their energy expenditure by as much as 60 to 70 percent.

Ground Effect
When flying closer to the water than the length of a single wingspan, pelicans benefit from a phenomenon known as ground effect. A cushion of compressed air forms between the bird’s wings and the water’s surface, creating additional lift and reducing drag. This allows them to glide efficiently with minimal wingbeats, producing the elegant, low-level flight that is so characteristic of the species.

V-Formation Flying
When traveling in groups, pelicans often adopt a V-shaped formation. The wingtips of the lead bird create spirals of rising air that provide lift for the birds behind. By riding these updrafts, trailing pelicans reduce their own energy expenditure and flap their wings less frequently.

But how do they decide who leads? The answer is simple: everyone takes a turn. As the lead bird tires, it drops back into the formation, and another pelican takes its place. In this way, the flock shares the workload, making long-distance travel more efficient for everyone.

Watching a squadron of pelicans glide effortlessly along the coast may look simple, but behind that graceful flight lies a sophisticated understanding of wind, waves, and teamwork that has been refined over millions of years of evolution.

What is a flock of pelicans called?
A squadron, a pod, or a scoop. When pelicans are seen swimming or flying together in an organized formation, they can also be called a fleet.

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