Brown Pelican Glottis Exposure: A Curious Seabird Behavior

By December 29, 2022January 19th, 2024Pelicans of La Jolla, Seabird

Glottis exposure — what is it?  A “glottis exposure” is a not-so-well described pelican behavior. I have seen it thousands of times among California brown pelicans but didn’t know the proper term for it until recently, when I became aware of some guy on Twitter who described what the behavior is and why pelicans do it.  His tweet generated some chatter about “glottis exposure”.  What is it?  It appears (to me) to be related to a pelican head-throw but in the opposite direction in a sense.  During a glottis exposure the pelican lowers his head and neck back and down in such a way this its throat pouch is pushed outward, inside out. It almost looks like the pelican is barfing its own throat out between its long bill mandibles!  I have not seen any definitive explanation about why pelicans perform this glottis exposure, but a number of seemingly knowledgable web articles suggest that it is to rearrange and perhaps stretch or flex the tissues of the neck and throat pouch.  I personally think it may also occur when there is some debris (think bits of fish or seaweed) that needs to be dislodged from the pelican’s throat or pouch.  In any event, the glottis exposure movement often precedes or follows a head-throw – I would say about half the time a glottis exposure move occurs, it will be followed a few seconds later by a head throw.  Here are some photos of the glottis exposure behavior for you to enjoy.  Cheers, and thanks for looking!

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38626
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38677
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38700
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38711
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

California brown pelican glottis exposure, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla

California brown pelican glottis exposure.
Image ID: 26289
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38855
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38856
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38857
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis californicus, Pelecanus occidentalis

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 39897
Species: Brown Pelican, Pelecanus occidentalis californicus, Pelecanus occidentalis

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38887
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38890
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla, California

Brown pelican glottis exposure. This pelican is inverting its throat and stretching it over its neck and chest in an effort to stretch and rearrange tissues of the mouth and throat.
Image ID: 38883
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

What do I mean by a brown pelican head throw?  Here you go:

Spectacular Brown Pelican Head Throw Display. This California brown pelican is arching its head and neck way back, opening its mouth in a behavior known as a head throw or bill throw, Pelecanus occidentalis, Pelecanus occidentalis californicus, La Jolla

Spectacular Brown Pelican Head Throw Display. This California brown pelican is arching its head and neck way back, opening its mouth in a behavior known as a head throw or bill throw.
Image ID: 38675
Species: Brown Pelican, Pelecanus occidentalis, Pelecanus occidentalis californicus
Location: La Jolla, California

About Phil Colla

I am a natural history photographer. I enjoy making compelling images in the ocean, on land, and in the air. I have maintained the Natural History Photography blog since 2005 and my searchable Natural History Photography Library since 1997. Here are some tear sheets and behind the scenes views. Thanks for looking!