Leona Kirk, who runs her business Wildlife Protection Services from Timaru, has two specially trained conservation dogs - a border terrier/fox terrier cross named Bail, and a spaniel named Katie, who were helping sniff out rats in the river bed last week.
Detection dogs have been used successfully along other braided rivers and have shown they can find rat nests, track rats and sometimes kill them, so a fulltime rat dog and handler is definitely on the ARRG’s wish list.
Leona and her dogs spent three days surveying the south bank of the Ashley/Rakahuri River where most rats have previously been caught.
ARRG spokesman Grant Davey says rats are the most destructive predator along the river and a recent boom in numbers means they pose the biggest risk to the endangered birds which breed there.
It appears there are similar problems in most other rivers.
‘‘Without a solution to the rat problem, BlackFronted Terns are on a path towards extinction,’’ Grant says.
It hoped to get Leona back during the nesting season for another three days.
‘‘If ARRG had its own rat dog and handler, it seems likely we wouldn't have a rat problem.’’
From 2004 to 2017 ARGG caught few rats, sometimes none in a year, in its traps along the river, making up a tiny proportion of its catch.
‘‘But since then numbers have boomed,’’ Grant says.
In the last year they made up more than half of ARRG’s catch.
‘‘We caught 383 Ship rats, 82 Norway rats and 54 of undetermined species from August 1, 2022, to July 31, 2023.’’
It is not known why the increase in rat numbers has occurred. The Norway rat is ARRG’s biggest problem.
‘‘We haven't seen or caught any Ship rats out on the river where the birds nest.
‘‘They are most often caught in traps under trees.
‘‘Ship rats don't directly threaten braided river birds, but they are no doubt a major predator for birds that nest in the trees,’’ Grant says.
However intensive use of trail (motion detection) cameras in the last three nesting seasons, and the catch in ARRG traps, has shown Norway rats to be easily the most lethal predator on the river.
‘‘They have completely wiped out several blackfronted tern colonies, eaten the eggs and sometimes the chicks,’’ Grant says.
‘‘They have also taken eggs from Wrybill and Banded Dotterel nests and are interpreted to have taken more than 100 BlackBilled Gull chicks from a colony in 2019.’’
Breeding rates of BlackFronted Terns have now plummetted to around one fledgling per 10 nests.
Leona says she began training dogs to do conservation work as a youngster.
‘‘I was fortunate to have been able to start training dogs at a very young age under the guidance of a good family friend who was the co-ordinator of the Conservation Dogs programme at the time, the late Scott Theobald,’’ she says.
‘‘Being raised in the rural Marlborough Sounds area and being homeschooled, I was already doing pest control around the age of 1314.
‘‘Scotty gave us our first pup, and I started training her to detect rodents, and was fully certified two years later.’’
She says the work she does with Bail and Katie is hugely rewarding but can also be confronting.
‘‘It can be really hard as well when you are constantly confronted by the enormity of the problem these birds are facing.
‘‘They really do have a lot stacked against them, so every little thing you can do to try and improve their chances of survival, or raising chicks, is absolutely worth it,’’ she says.
‘‘It is an amazing feeling when the team is responsible for really messing up a rat's day.
‘‘Whether that is through the trappers and their trapping programme, or with the dogs.’’
By Shelley Topp
