Friday, June 11, 2010

Gull eating sea star, Discovery Park

Among the many talents of the ubiquitous glaucous-winged gull: sea-star swallowing.

It takes some effort.


My mouth would feel odd too.

Looking a little lumpy.


Dave Riddell said...

Hi Fiona! You might be interested in this research presented at the Bamfield Marine Sciences Centre here on Vancouver Island last year: see page 10 —

Fiona Cohen said...

Wow, Dave, that's amazing. Here's an excerpt from the story he sent, about some research being done by a Simon Fraser University graduate student called Justin Suraci.

"Gulls have been known to eat sea stars bigger than their head, sometimes standing around for 30
minutes to swallow the whole star. Considering the time it takes to choke one down. The star must
either have 40 times the nutritional value of anything else on the beach or it offers something the gull can’t
get elsewhere. Justin Suraci wonders whether the birds might be in it for the saponins, pharmacological
compounds found in many plants and no animals except for sea stars and sea cucumbers. The saponins,
or perhaps a star’s spiky ossicles, might help rid the gull of gut parasites. Suraci, a graduate student
studying avian behavioural ecology at SFU, hopes to find out by offering Pisaster ochraceous stars to groups
of glaucous-winged gulls with and without intestinal flukes (or varying levels of fluke infection in the
field)—an experiment that may call for a captive gull colony. If the gulls troubled with parasites go for
the stars, it would be the first experimental approach to analyzing an avian self-medicating behaviour.
Self-medicating—where an animal changes its diet while sick, likely to try to cure it’s ailments—has been
seen in chimpanzees but rarely elsewhere. “If self-medication is more common than we think, it could add
another layer of ecological interaction,” Suraci says. The presence of organisms preyed on medicinally “could
even inform conservation efforts.”