In Maryland, a renewed effort to eradicate swamp rats from the Delmarva Peninsula

(AMIRAN WHITE/NEWS-REVIEW VIA ASSOCIATED PRESS) - A nutria bares its red, beaver-like teeth near the duck pond at Stuart Park in Roseburg, Ore., in 1997. Maryland wildlife officials have been trying for years to eradicate the pesky rodents that are destroying a Chesapeake Bay marsh. Last week, officials were given strict orders to kill all of the remaining nutria.

On the muddy edge of the Wicomico River, where tall grass hides all sorts of vermin, Stephen Kendrot and his patrol of federal wildlife biologists tracked the dirty rat that’s destroying precious Chesapeake Bay marsh.

A near-decade-long federal and state effort to get rid of nutria, or swamp rats, killed 13,000 of the giant rodents but failed to eradicate them from the Delmarva Peninsula. So Kendrot and his team at the Blackwater National Wildlife Refuge got strict final orders last week: Find the last survivors. Kill them all. And when it looks like they’re gone, go back and make sure.

More on this Story

View all Items in this Story

Standing in a wobbly johnboat near Salisbury, Kendrot, the ­nutria project leader for the U.S. Department of Agriculture’s Wildlife Services — which has a little-known SWAT team of professional animal killers — spotted a telltale sign of the beast and called to his men. “Is that a tail drag there?” Kendrot asked, looking at the bank.

Up ahead, biologist Mario Eusi followed some smudged tracks and hit pay dirt: depressions in the mud where a clan of swamp rats had fed. As always, they had ripped up plants by the root, eroding the land that supports the marsh that nurtures blue crabs and juvenile fish.

“If you like crab cakes,” Ken­drot said, “you ought to be worried about nutria.”

Eradicating this semiaquatic invasive species native to South America is easier said than done. Not only do they look like rats — with twin buckteeth and long tails — they also breed like them.

Female nutria give birth to litters of up to 13 and go back into heat in two days. Basically, they’re pregnant all year, every year, until they die of old age at 8 to 10. They have nipples on their backs so the young can feed while the mother is swimming.

In the days since the new eradication order was handed down, Kendrot and his team have seen evidence of several nutria colonies along the 24-mile Wicomico River, spotting ripped out plants and droppings in places where swamp rats had never been seen.

The biologists can’t set traps along the river until homeowners in the area grant them permission. The rusty traps are square like a slice of bread and quite effective, said USDA wildlife biologist Daniel Dawson, who demonstrated how to set one.

Dawson made a bed of cordgrass the way the nocturnal rodent likes it. To make it even more appealing, he scented it with several drops of swamp rat urine he kept in a sports drink bottle. Finally, he set the trap at the entrance to the bed.

“When they climb through and hit the trigger — bang,” Dawson said as the trap snapped shut with a hard, metallic pop. A perfect strike instantly breaks the rodent’s neck.

The USDA hopes to eradicate the animal in the Delmarva Peninsula — which stretches from north of Dover, Del., to near Virginia Beach — by the end of 2015.

The Blackwater National Wildlife Refuge in Cambridge, Md., has about a dozen of the rodents in cages, candidates to wear radio tracking devices that lead to colonies. An unfortunate worker swabs their anal glands for scent markings that can lure nutria into traps.

 
Read what others are saying About Badges