In an earlier post, I gave an update on the unusual Brown Pelican mortalities reported on Topsail Beach in North Carolina. Some of the pelican carcasses were submitted to the Southeast Cooperative Wildlife Disease Study (SCWDS) for necropsy, and the final results from those examinations are now available. Dr. Kevin Keel, a wildlife pathologist at SCWDS, wrote that the birds varied in age from juvenile to adult. All were in good nutritional condition, not thin. All the stomachs contained fish (menhaden, croakers, and “yellow-tails”) which had been ingested very recently. X-rays of the birds showed no fractured bones, and no shot pellets or other metal fragments. One bird had fluid in the air sacs that lie under the skin in birds.This was speculated to have been seawater, as the bird was also soaking wet to the skin. The birds were tested for viruses, algal toxins, heavy metals and some other contaminants; all tests came back negative. There were no underlying diseases diagnosed in any birds.
So where does that leave the investigation? These results rule out deliberate, human-inflicted gunshot or bludgeoning as suggested in the local media, but they do not give a clear cause of death.
Entanglement in fishing nets still seems a very likely possibility. The presence of fluid in at least one bird’s air sacs is consistent with (though by no means absolutely indicative of) drowning. Also, the very recent ingestion of only a couple species of fish across all the birds suggests that they were actively feeding when they died. This also points toward a fatal interaction with fishing gear. There is no way to know for certain, but this thorough investigation shows the merits of necropsies in such cases–without the work done at SCWDS, the speculation that people deliberately shot or beat the birds to death would likely have prevailed.
In other dead pelican news, Lorrie in Guilford Connecticut found a very interesting item on the beach there. She looked up SEANET and got in touch via this blog with a photo of a bird very far outside its accustomed range: a rather well decomposed and somewhat mummified American White Pelican! In perusing the reported sightings of that species on ebird.org, I find one report from November 2003, one from October 2008, and one from December 2009. So these birds, live or dead, are a novelty up here in these parts. Lorrie’s not a Seanetter yet, but we’re hoping she will be soon as she clearly has an eye for dead birds. So thanks Lorrie!