What's
wrong with this picture?
(back to report)
Here is a closer look. Now do you notice anything unusual about the crane's plumage? Look again and compare to these cranes (# 1, #2, #3). Then find the answer below...
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Crane biologist Tom Stehn explains:
This is a family (2 adults:1 young) of whoopers that have stayed on the Platte River in Nebraska since 10/23. As you can see, they are stained on the legs and belly—with what, we don't know. The most popular theory seems to be oil.
We don't know if the black staining was caused by oil but for now we have no other theories. The 3 cranes all apparently walked or landed in water containing the substance that was deep enough to coat their legs and bellies.
This message from contaminants expert Peter Albers at Patuxent Wildlife Research Center provides a positive outlook to what we think is an unprecedented situation. So far, the behavior of the birds is considered normal in all aspects!!!!
"The durability of the staining and the uniform pattern on all three birds are compatible with some type of oil-based staining that occurred as the birds were wading through water. The dark brown (almost black) color would indicate exposure to either crude oil (oil field waste ponds), lubricating oils from waste water retention ponds (industrial or refining complexes), or one of the heavier fuel oils (Nos. 4-6). Gasoline and kerosene would have produced little visible stain and diesel fuel would have left a light brown stain. There is probably little to worry about if the cranes continue to look and behave normally. I would begin to worry if their feathers start looking unkempt and the birds become lethargic."
Peter H. Albers
USGS Patuxent Wildlife Research Center, Beltsville Lab
Field personnel monitoring the crane family have collected a fecal sample, but have been unable to find any 'stained' feathers at the roost site. We'll planning to get the fecal sample analyzed to see if it contains any oil-based substances. Right now the situation calls for continued monitoring!
Tom Stehn
October 27, 2006
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The "stained" family group arrived at Aransas National Wildlife Center in Texas for the winter. "A family group that is stained brown on the legs and bellies that may have walked into a pond containing an oily substance sometime during the migration was located on their territory on Matagorda Island," reported Tom Stehn. "One of the adults was banded YbY-Y in 1987 and was last observed on November 7th at Salt Plains National Wildlife Refuge in northern Oklahoma. This family was believed present at Aransas on the November 15th flight, but on that day we were unable to fly low enough to see the staining on the legs. Although the discoloration is clearly evident, it is difficult to see from the air as you’re looking down on the birds. From my brief look from the air, the family seemed to behave just like any other cranes." |
Journey North is pleased to feature this educational adventure presented in cooperation with the Whooping Crane Eastern Partnership (WCEP).
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