The loons are OK -- so far, but DNR is looking at long-range impact of Gulf oil spill
Many would argue that the spring return of the common loon is one of the best parts of living in the lakes area. Minnesota's state bird migrates north every spring from wintering grounds along the Gulf coast to breed in Minnesota.
The April 2010 Deepwater Horizon oil spill, which released about 4.9 million barrels of crude oil into the Gulf of Mexico, had many Minnesota biologists, hunters and bird watchers worrying about the biological impacts that disaster would have on Minnesota's migratory bird populations.
The DNR is now in the middle of a three-year study to look at the impact of the largest accidental marine oil spill in the history of the petroleum industry on the common loon and the white pelican.
According to Minnesota Department of Natural Resources Regional Non-Game Specialist Katie Haws, preliminary reports on some pelican eggs taken from the Marsh Lake nesting area show signs of oil.
"They have found evidence of petroleum compounds and also of the dispersants, the chemical used to clean up the oil, in the eggs," Haws said. "But we don't know what the effect -- they're called polycyclic aromatic hydrocarbon -- we don't know what specific effects that will have on the pelican."
She said the DNR has also sent 13 dead loons they collected in 2011 to the Madison Wildlife Health Lab in Wisconsin for muscle tissue analysis, but those results aren't available yet.
While many species of birds migrate from Minnesota to parts south, Haws said the loon and pelican were chosen for this study because biologists specifically knew the birds winter in the Gulf and nest in Minnesota.
"Songbirds probably weren't impacted," she said. "But both of these water birds were two we felt quite confidant were spending a lot of time in the Gulf of Mexico in the winter and also did breed in Minnesota."
Haws said about 70 percent of the nation's population of white pelicans, about 17,000 nesting pairs, breeds in the Marsh Lake area of west-central Minnesota.
As far as her gut feeling to the end results of the study, Haws said there will be some impact but what that impact is the big question.
"Any time you have toxic chemicals, they can have an impact," she said. "Other toxic chemicals you've probably heard of, like DDT, ended up effecting birds through the egg shells thinning."
With thinning eggshells, many birds' young weren't surviving to hatch, she said.
"That took years before they figured out how that worked," she said.
She said the end result of this study will tell the DNR if there are chemicals present, but won't give a clear picture as to the impact of those chemicals.
"That's why we have some other studies that we were already conducting that will help us to monitor (breeding success)," Haws said.
Pelican numbers in Minnesota have been monitored every five years, she said. The Minnesota Loon Monitoring Project, which is in its 18th year, relies on volunteers to count the number of loons on about 600 lakes throughout Minnesota on a specific day in July.
"We thought if we saw a huge drop in 2011, that will tell us there was something major going on," Haws said. "And the good news is that we didn't see that at all in 2011. The numbers appeared to be very consistent with the other years.
"That tells me that there may be some level of the hydrocarbons in the tissue and the eggs, but it must not be at such high levels that productivity, at least in the case of the loons, is hurting."
The study is funded through 2014 by a $250,000 grant that came from the state Environment and Natural Resources Trust Fund. The yearly Minnesota Loon Monitoring Project will continue to be an ongoing survey, which is constantly searching for volunteers.
To volunteer as a loon observer, call Haws at 218-308-2641.
(Follow Basham on Twitter @DLcameraguy.)