Between planning our impending move to Asheville in January, traveling to Minnesota for the Holidays, plowing through some freelance assignments that all rolled in at the same time, wrapping up the Blog Column of the Week for 2010, and working on my book (ha! supposedly…), blogging has gotten a bit lost in my daily fray. I miss cyber musings! The worst part about being too busy to breathe is that that’s when I seem to notice all these great blog post ideas floating around.
One such idea that popped up in my email inbox last week was a press release about a University of Florida experimental study examining the effect of mercury on white ibises.* These birds, if you are unfamiliar, are gorgeous. Nothing screams Florida! to me than seeing a flock of these snow-white birds careen overhead with their curved fleshy-pink beaks silhouetted in the orange dawn light. Settlers to southern Florida in the olden days referred to them as Swamp Chickens because they lived in the swamps and, well, they supposedly taste like chicken. The juveniles and first-year birds are a splotchy mess of brown and white feathers, but the adult are pure white with a curved, salmon pink bill. They use this bill when they wade in the shallows of lakes and swamps where they probe the mud for little reptiles, amphibians and fish. In breeding season, the males develop dark black tips on their wing that read like a personal ad: I iz reddy, chiks!
So it was with a little dismay that I learned UF researchers had found that exposing white ibis males to experimental levels of mercury causes hormonal shifts that spurs them to try mating with other males. The Miami Herald seized on this to say that mercury makes ibises gay, and National Geographic was not far behind. Let’s face it, the media loves gay animal stories.
So what was really going on?
It turns out the scientists were interested in learning whether mercury pollution in the wild affected white ibis reproduction or chick development. Mercury pollution was a problem historically in southern Florida. (Is it still? Anyone know?) A press release says: “The contaminant found its way into the Everglades via municipal and medical waste incineration, but during the 1990s, medical waste became more closely regulated and flashlight batteries that didn’t contain mercury replaced those that did.” So we can deduce from this that from the mid-1990s till now, supposedly mercury pollution has been lessening. (Someone holler out if they know it’s worsened.)
UF wildlife and ecology professor Peter Frederick had noticed that in the late 1980s and early 1990s, white ibises were not producing many chicks. This correlated to a time period when mercury levels in the Everglades were high. But as researchers began to solve some of the hydrology issues to restore the natural water flows to the Glades — early settlers, and later the Army Corps of Engineers, had ditched and drained large swaths for agriculture — and as environmental regulations of the contaminant kicked in, Frederick noticed that white ibises began pumping out chicks again.
To investigate if the mercury correlation was causative, he and some colleagues set up an experiment to expose white ibises to mercury and test for reproductive outcomes.They used 160 young white ibises and parsed them into four groups composed of equal numbers of males and females. One group was used as a control, but the unfortunate other three were fed diets that represented a range of low, medium and high mercury contamination. The doses supposedly mimic the range of mercury pollution the birds may encounter in the wild (or that occurred historically? I don’t know! Don’t have a copy of their paper…).
What they found stunned them, even Frederick. Females dosed with high-levels of mercury produced 35 percent fewer chicks than the control group. But it was the males that stole the show. They started shacking up together. A press release stated that in 2006, about 55 percent of the high-mercury-diet males nested with other males, and as the mercury exposure increased, so too did the number of male-male pairings. Females were also less likely to approach the high-dosed males, and all of the mercury-dosed males (no matter the concentration) were less likely to perform their ritual courtship displays.
“We knew that mercury can disrupt hormones – [but] what is most disturbing about this study is the low levels of mercury at which we saw effects on hormones and mating behavior,” Frederick said in a press release. “This suggests that wildlife may be commonly affected.”
So were the male-male pairs just roommies? Like Chandler and Joey on Friends? Not quite. Christine Dell’Amore reported the nitty-gritty for NG Daily News:
These “male-male pairs did everything that a heterosexual pair would do,” said study leader Peter Frederick, a wildlife ecologist at the University of Florida in Gainesville.
“They built their nest, copulated together, stayed together on a nest for a month, even though there were no eggs—they did the whole nine yards.”
Wow. Put this in your Noah’s Ark Theme Park, Kentucky!
The multitude of ways we are altering our environment and screwing with other species never cease to amaze me.
And the birds in the three-season long experiment? The scientists fed them a diet to “cleanse” the mercury from their bodies and released all the study subjects, and their offspring, back to the Everglades.
So, anyone hungry for some Swamp Chicken?
* I don’t typically write posts straight off press releases, but for full disclosure, I used to work with the UF News Desk crew, and I know the person who wrote this one. She had a long career as a newspaper journalist before coming to UF, so I’ve a degree of trust here.