Bald eagle nesting activity expanded across much of Georgia this year, but Augusta-area populations of the rare birds continue to suffer from a mysterious, fatal disease.
A Georgia Department of Natural Resources survey documented 73 occupied eagle nesting areas this year - nine more than last year. The nests spanned from Murray County in the north to Lowndes County in the south.
Those areas included 51 nests that were successful in fledging 84 young eagles, said Jim Ozier, Georgia's senior Wildlife Resources Division biologist. Last year, 50 nests fledged 92 young.
"Since nesting activity fluctuates, the fact that this year's survey indicated eight fewer eagles as compared to 2001 is not cause for alarm," he said. "Long-term trends point to a growing eagle population in Georgia."
Thurmond Lake near Augusta attracts large numbers of bald eagles - averaging nine nests in normal years. However, outbreaks of avian vacuolar myelinopathy have stricken those populations.
David Brady, district wildlife biologist for the Army Corps of Engineers, said two active nests were documented along Thurmond Lake this year, compared with only one last year.
"That doesn't mean it's getting better, though," he said. "Three years ago, there were six - and we usually had nine before that."
Lake Russell upstream from Thurmond Lake had one nest last year, doubling to two this season, he said.
"When you go from nine to two at Thurmond, you have a problem," Mr. Brady said. "The good news is we had an active nest last year at Russell and now we have two, so maybe the eagles up there (are escaping) whatever is killing them at Thurmond."
Three eaglets were fledged from the two Russell nests, compared with one eaglet from the two Thurmond Lake nests.
About 24 bald eagles have been killed by AVM - a fatal brain disorder - along Thurmond Lake in the past three years, despite efforts to identify and eliminate the causes of the disease.
Although AVM's origins remain a mystery, studies by the U.S. Fish & Wildlife Service suggest the source is an environmental toxin and not a traditional disease.
One theory is that small waterfowl called coots, which feed on aquatic vegetation such as hydrilla, ingest material associated with an algae bloom and produce toxic agents fatal to eagles, which feed on coots.
"No one knows for sure, but the hydrilla is where the evidence seems to be stacking," Mr. Brady said. "Hydrilla is in the area where most of the eagles are being lost."
Last year, 12 Canada geese from Thurmond Lake tested positive for AVM, which is believed to affect only birds and not mammals.
Bald eagles declined in the 1950s and '60s because of widespread use of the now-banned insecticide DDT, which was passed to eagles through small creatures they consumed. In the 1970s, Georgia had no eagle nests.
Bald eagles have made a slow but steady comeback since DDT was discontinued, and the birds enjoyed protection under the 1973 Endangered Species Act. The birds now are proposed for delisting from that protection.
Reach Robert Pavey at (706) 868-1222, Ext. 119, or firstname.lastname@example.org.