Even with deformities, loons able to survive
Cormorants with misshapen beaks will die but loons seem able to adapt and carry on
The female loon on a Wisconsin lake was still swimming, looking for all the world like one of those Second World War photos of an aircraft shot full of holes that somehow made it home.
The upper half of the animal’s beak was bent sharply upward at a bizarre angle, raising all kind of questions: How could it catch fish? How could it eat if it did catch something ?
Yet the female was surviving, teaching even veteran scientists a lesson in just how tough these birds are. Or as Walter Piper puts it, “Loons hang in there through adversity.
“The deformity was obvious back on May 17, when we first saw her,” he wrote in his blog on the Loon Project, where he sums up three decades (and counting) of watching loons on 200 lakes. “We were alarmed at her situation, which appeared uncomfortable, at least, and deadly, at worst. But she behaved normally. ... Her diving and foraging was normal.”
Piper, who studies loon behaviour, turned to Mark Pokras, an expert in veterinary medicine at Tufts University, for information on the medical side.
He says that Pokras “assures me that the fact that the bony foundation that should extend to the bill tip is missing means that it ‘will never grow back normally.’ The best we can hope for, he says, is that the bent keratinized tissue — all that remains of the end of her upper mandible — drops off eventually. I was chagrined to hear this news but heartened to learn also that Dr. Pokras has, during his decades of loon anatomical study, seen about 10 cases where large portions of loon bills have been missing.
“These cases include a male in Maine that had only half of an upper mandible (as this female does) but that fed itself normally, held its territory, and produced offspring in multiple years.”
Beak injuries to birds are never trivial. One of the important forms of damage to wildlife caused by “hot spots” of pollution in the Great Lakes has been crossed-bill syndrome, in which cormorant are born with bills whose top and bottom halves don’t line up properly. Despite their parents’ care, the chicks die.
But loons are survivors. Female loons can live to 30 years of age in the wild.
It got Piper wondering why: “That loons can survive an injury of this kind to a crucial feeding organ and still breed seems remarkable. I suppose their resilience might be explained partly by the challenges they face routinely across the range of different landscapes they inhabit. That is, an animal that must locate, pursue and capture a broad spectrum of actively swimming prey — in water that is sometimes fresh, sometimes salty; sometimes clear, sometimes turbid, must be a flexible and adaptable creature indeed.”