Gular Pouch of the California Brown Pelican February 2018

The gular pouch of the Brown Pelican is a natural wonder in both form and function. The pouch is massive, expandable and consists of specialized skin that is as tough as kevlar and elastic-like in it's ability to expand enough to hold 3 gallons of water. Pelicans use the massive pouch like a great net to scoop up prey; once a fish is caught, the pelican contracts it's pouch to expel the water before swallowing the meal. Their pouch is extremely resilient and perforation resistant; even the sharpest dorsal fins will not lacerate the skin of their gular pouch. Please view this informative and fascinating video https://www.youtube.com/watch?v=U3NqXnWxccg Dissecting with Emily Gular Pouch and Mouth Anatomy.

Bald Eagles and raptors were not the only birds affected by the use of DDT; in fact hundreds of species were adversely affected and during the 1960’s and 70’s, the California Brown Pelican was facing extinction. DDT disrupts calcium metabolism resulting in defective egg shell development. The thin shelled eggs were either incompatible with life or broken during incubation; in either case the thin shells resulted in reproductive failure. In 1971, the Brown Pelican was listed as an endangered species and in 1972, DDT was banned; because of conservation efforts, the Brown Pelican population is now strong and viable. In 2009, nearly 40 years after Brown Pelicans were listed as endangered, they were removed from the Federal endangered species list. Pelicans remain vulnerable to chemicals, oil spills and nesting disruptions as they will hastily abandon their nest and eggs when disturbed.

California Brown Pelican (Pelecanus occidentalis)
The gular pouch is massively expandable and it can hold up to 3 gallons of water (which is an astonishing 24 pounds of liquid). Note that the lower mandible is shaped like a hoop to support the pouch. The gular pouch functions like a great scoop or net allowing the bird to capture and hold it's prey.
brown pelican pelicans occidentals head throw gular pouch bird la jolla california
California Brown Pelican (Pelecanus occidentalis)
A closer view depicts the capillaries in the gular pouch; the capillaries provide blood supply to the pouch and function to dissipate heat and cool the animal.
brown pelican pelicans occidentals head throw gular pouch bird la jolla california
California Brown Pelican (Pelecanus occidentalis)
The gular pouch is puncture resistant and allows the Pelican to trap sharp spined prey while avoiding gular injury. Note that this pelican has a fish in it's pouch; the dorsal fin spines are visibly protruding.
brown pelican pelecanus occidentalis gular pouch la jolla california bird wildlife
From Brown Pelicans of La Jolla California - January 2016
California Brown Pelican (Pelecanus occidentalis)
An additional function for the gular pouch relates to courtship as it turns a vibrant red during breeding season to attract prospective mates.
brown pelican pelicans occidentals head throw gular pouch bird la jolla california
California Brown Pelican (Pelecanus occidentalis)
Everting it's gular pouch is a behavior to maintain the health of this organ. Note the hook on the upper mandible (maxilla); the hook functions to hold slippery struggling prey. Pelican bills are the longest of any species on earth; an Australian Pelican bill may reach a length of 18 inches.
brown pelican pelicans occidentals head throw gular pouch bird la jolla california
California Brown Pelican (Pelecanus occidentalis)
A closeup of the upper mandible and anterior hook that functions to secure struggling prey.
brown pelican pelicans occidentals head throw gular pouch bird la jolla california
California Brown Pelican (Pelecanus occidentalis)
A California Brown Pelican engaged in "head throw" behavior. Pelicans frequently toss their heads backwards, open their beaks, and expand their gular pouch. The maneuver is most likely a means to maintain the health and elasticity of pouch skin, La Jolla, California, February 2018.
brown pelican pelicans occidentals head throw gular pouch bird la jolla california
Eventide
My time in California with the Pelicans was a magical experience; I will miss these gentle prehistoric beings and their magnificent habitat. Farewell my feathered friends; until next year...
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