Who killed the geese at Fernhill?
Oregon Department of Agriculture investigates possible misuse of zinc phosphide
Last month, Clean Water Services staff began to receive reports of dead cackling geese at Fernhill Wetlands.
They immediately tested the water and found toxic levels of blue-green algae, which has been known to kill dogs and other animals that come into contact with it. Uncertain whether the algae killed the geese, staff opted for caution and posted temporary signs instructing visitors to avoid contact with the water.
They also sent six geese carcasses to Oregon Fish & Wildlife for testing.
We wanted to make sure it wasnt a Fernhill problem, said Sheri Wantland, public involvement coordinator for CWS.
While the blue-green algae eventually subsided to safe levels and CWS staff removed the warning signs, a lab analysis released last Thursday, Oct. 1, showed Fernhill and blue-green algae had nothing to do with those early geese deaths.
Instead, results showed the geese died from ingesting zinc phosphide, likely while grazing in fields where the chemical is used to control voles.
CWS staff tested its various properties for zinc phosphide but found none, Wantland said. We wanted to make sure it wasnt coming from the fields we own.
While CWS and ODFW will continue to monitor the situation, Wantland said, we want to emphasize that its not a Fernhill problem, other than the fact that thousands of geese pass through Fernhill to rest and feed and some inevitably die there, leaving carcasses for visitors to wonder or worry about.
Wantland estimates at least 20 geese carcasses and perhaps as many as 30 were found on Fernhill property over the past month.
Dead geese are also likely showing up other, less public places, she said.
This rash of geese deaths was unusual. Years ago, a rash of geese deaths was due to bacteria in grain that geese were eating, she said. Again, not a Fernhill problem, but one CWS got involved with due to concerns expressed by the public who visits Fernhill.
Julia Burco, a wildlife veterinarian with ODFW who helped analyze the first batch of geese carcasses from Fernhill, said she just received another batch of 10 to 14 dead geese from Fernhill Monday and will do a full workup on them to see whether they died from the same cause. Results usually take a week or two, she said.
Historically, we have had some issues with cacklers dying of zinc phosphide before, she said. Someone might be misreading the label and incorrectly applying the pesticide, she said.
Its supposed to be below-ground application, she said, and if someone sprinkles it on top, cacklers are more predisposed to ingest it because they eat on top of the grass.
Dale Mitchell, pesticide program manager for the Oregon Department of Agriculture, said the agency is trying to determine the source of the zinc phosphide and the possibility of unlawful use of pesticide products.
Zinc phosphide is a restricted-use pesticide, Mitchell said, and requires a license to buy it. With a list of registered dealers, ODA will be able to find out who bought the pesticide and when, he said, and can start investigating buyers.JW_DISQUS_ADD_A_COMMENT