Through thousands of blood samples taken over the past 30 years, they found these birds — a relatively common sight on many New England lakes — were suffering from lead and mercury poisoning as well as other pollutants.
But the researchers took some solace in knowing that loons, unlike birds that frequent more tropical climates, weren't being sickened by avian malaria.
That, however, is changing.
Pokras and Ellen Martinsen, a Vermont-based research associate with the Smithsonian Conservation Biology Institute, started finding several different malaria parasites in loon blood samples a few years back. The latest data show as many as 12 percent testing positive, though not all are expected be infected with malaria.
Then last summer, the researchers found the first ever case of a loon — on Umbagog Lake located in Maine and New Hampshire — that died of the disease. Biologists and fans of the loons haven't found another case yet, but they are looking for other dead birds.
Groups like the Loon Preservation Committee — whose offices are on the loon-populated Lake Winnipesaukee in New Hampshire — have advised their volunteers to step up surveillance on lakes across the state. The Maine-based Biodiversity Research Institute has also started a crowdfunding campaign to raise funds to further investigate the extent of the problem.
"I wouldn't call it alarm bells but it certainly is raising eyebrows and emphasizing the need to look more," said Pokras, an emeritus associate professor at Tufts University who is writing a book on loons. "It may certainly be this bird that died was unlucky or maybe it had some immune deficiency that made it more susceptible to the parasite. I doubt it but we don't know that yet."
Martinsen, who used molecular methods to screen the loon population for malaria parasites, said the concern is that the birds may not have defenses to protect them against an infection — much like humans with Ebola or West Nile "which wreaks havoc on our system."
"We may be at the edge of discovering an emerging infectious disease of common loon which is pretty significant because it's a vulnerable species," Martinsen said. "It's experienced significant population declines."
Scientists believe the presence of the malaria parasite in loons offers further proof that climate change already is taking a toll on the region. As temperatures rise in New England, a parasite found more commonly in birds down in Florida, Georgia, and Louisiana appears to be moving north.
Read more at Loon's Malaria Death Seen as Sign of Climate Change
No comments:
Post a Comment