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Kleptoparasitism: Thieving Gulls steal from Pelicans

Dewees Inlet is a fun, dynamic place to watch nature: the tide moves quickly, dolphins regularly cruise looking for food, and there is a wide selection of birds.  When schools of baitfish are moving through the area, the action really heats up!  The main dock on Dewees and the decks of the ferry are both great places to watch what’s going on.

We were lucky to be headed to the main dock the other day after a storm, and there was clearly something going on:  gulls and pelicans waited expectantly on the water, and the silvery flash of a dolphin’s dorsal fin was regularly visible above the waves.  The sun was low on the horizon, and we paused to watch for a few minutes.  I am trying out a new camera, so I thought I would see what I could catch in the waning light.

dolphin breachingPelicans were diving from short distances to catch fish, and they were being watched carefully by several laughing gulls floating nearby.  Remembering a time I had seen a gull sitting on a pelican’s head in that same location, I raised the camera, but it didn’t focus quite fast enough in low light.

pelicans and seagullsWe waited and watched.  The pelican dove again, opening its beak near the surface of the water:

Two laughing gulls swooped in to see if there was a chance the pelican might drop the fish:

It turns out that this is a fairly common occurrence called kleptoparasitism: when one organism steals from another as a more efficient means of procuring food that catching it themselves. Kleptoparasitism occurs across the animal kingdom: eagles steal fish from osprey, hyenas chase lions off their killed prey, flies scavenge half-eaten bugs from spiderwebs.  And in the inlet, we get front row seats for kleptoparasitism, watching laughing gulls attempt to grab a fish from a pelican.  Because gulls can’t dive beneath the surface for food, they watch the pelicans, who can dive farther.  As the pelican dives, he scoops up a large amount of water with the fish (2-3 gallons) which he drains from the pouch by lowering his head and pushing the water out the sides of the bill.  Sometimes fish or fish parts may be lost, providing a snack for the opportunistic gulls.  In the photo above, the gull on the right has found part of a fish atop the waves.  Below, the gull appears to be asking for a handout:

kleptoparasitism: gulls and pelicans

If you’re a gull, and you are tired of flying around, trying to guess where a pelican might drop a snack, the easiest thing you could do is find a high vantage point to watch for leftovers.  What could be better than sitting right on top of a pelican’s head?

2 thoughts on “Kleptoparasitism: Thieving Gulls steal from Pelicans

  1. A charming tale! As long as we have lived in the Lowcountry, we continue to be intrigued by the marvels of nature! We are particularly fortunate on Dewees to have the watchful eye of Judy to “see” what we can’t see and to share the delights of nature that abound around us. A Master Naturalist, Judy combs the skies, the waters, the beach and the marsh by habit everyday, blogging her passion. Stay tuned. None of us can imagine what might be seen tomorrow through her camera’s eye!

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