American White Pelicans eat fish almost exclusively and the size range of fish they’ll attempt to swallow can be extreme. If they show poor judgment they can get into serious trouble.
Some may remember images I posted of this pelican trying to swallow a headless carp at Bear River Migratory Bird Refuge. The fish was so big I was surprised that the bird even made the attempt but it must have thought there was a possibility of success because it spent a long time trying to get it down.
The commotion of the attempt caused other pelicans to try to steal the fish away from its possessor. Here the original bird, after numerous failed attempts at swallowing the carp, is carrying the same fish within its pouch as another pelican reaches from behind and between its wings and bites the pouch containing the carp. These birds have a mean-looking “mandibular nail” on the end of their upper bill that is useful in holding on to slippery fish but here it can be seen in action as it’s used for another purpose. Kleptoparasitism (stealing food from other birds) is common among pelicans and the attempts have been documented to be successful 37.5% of the time.
But the pelican diet is not restricted to large fish and I was able to document that fact yesterday morning at Bear River.
Unlike the plunge-diving Brown Pelican, American White Pelicans feed by swimming on the surface, dipping their bills into the water, scooping up fish in their pouch and then raising their bill above horizontal for swallowing.
I watched and photographed that process with this bird for quite a while, hoping to get photos as it swallowed a fish but my efforts were largely frustrated. It looked like the pelican was swallowing something but whatever it was I could never see it through my lens. This was the best look I got into the pouch.
But when I arrived home and looked at the images on my screen I could see (in a couple of shots) what it was eating. Very tiny fish. The fish I photographed in the bill and pouch didn’t look much larger than plump toothpicks. I was somewhat surprised that it’s apparently energy-efficient enough for them to go after such small prey. Since many attempts at them are unsuccessful the effort must use up almost as many calories as they get from such small snacks.
I also notice an apparent puncture wound on the neck and just below the base of the pouch of this bird and wonder if it was caused by the mandibular nail of another pelican during an altercation.
Side-note #1: Plunge-diving (from the air into the water) for fish has actually been observed twice in American White Pelicans – both instances occurred at Pyramid Lake, Nevada. Makes me wonder if that feeding tactic might one day appear as more typical behavior in American White Pelicans…
Side-note #2: Pelicans can get into serious trouble by trying to swallow fish too large or fish carcasses with exposed bones and spines. An example can be seen here and it’s an interesting read.