SASKATOON -- Health Canada has banned the use of strychnine bait to kill Richardson’s ground squirrels, commonly referred to as gophers, due to risks for non-target animals, including species at risk.
A Saskatchewan Ministry of Agriculture study submitted to Health Canada found one poisoned Richardson’s ground squirrel carcass on the surface of a treated site for roughly every 20 burrows treated.
That study also observed hawks, grouse, crows, grackles, swallows, meadowlark, songbirds, coyotes, foxes, antelope and badgers present at the plots. Three of four dead deer mice found at the sites were killed by strychnine.
"Observations recorded during the study period confirmed that non-target animals were actively scavenging these carcasses within the treatment plots," Health Canada said in its decision released Wednesday.
"Although the results from this study did not conclusively determine that predators or scavengers had consumed a lethal dose of strychnine through scavenging of poisoned carcasses (as no dead predators or scavengers were reported), there is evidence from previous studies and incident reports that secondary poisoning does occur."
Bait can also be ejected from the burrows to be eaten by other creatures - and placing the bait deeper into the burrow or covering the burrow isn't ineffective at reducing the number of poisoned ground squirrels available on the surface or the frequency of bait ejections from treated burrows, Health Canada says.
The products will be phased out within one year.
