A new study indicates widespread and long-term declines in loon populations across the birds' southern breeding range.
But Maine appears to be a bright spot, where loon productivity — the number of surviving chicks per breeding pair — is growing slightly, according to the research from Birds Canada.
"We actually found little evidence to suggest decline in productivity in Maine, and it actually showed that over the past 35 years, Maine's remained relatively stable," said Matt Fuirst a research ecologist at Birds Canada.
Fuirst and fellow researchers looked at decades of observations on thousands of lakes and ponds across Canada and the northern U.S.
The group found a 40% average decline in chick production across loons' range, with much steeper declines in the Canadian prairies and Maritime provinces.
Fuirst said that construction and development, pollution and contamination from lead fishing sinkers are threats to loons. But the effects of climate change, including more acidic rainfall and decreased water clarity from increased storm runoff may also be hurting loons' success at finding and catching fish, Fuirst added.
"We didn't test what is causing these declines. We know that the threats vary by regions and some of the regions of where loons breed may be experiencing different threats," Fuirst added.
Maine Audubon, which monitors loon populations in the state, said the population estimate this year was almost 2,800 adults and 276 chicks.
Conservation Director Sally Stockwell said in a statement that the organization is familiar with the Birds Canada study and concerned about widespread declines of the birds in North America.
Stockwell added that Maine's adult population seems to be doing well and chick production has remained more or less steady over the decades.
But "some more recent limited monitoring of breeding success does suggest that our overall productivity is also below what's needed to sustain a population long-term," Stockwell added.
