Alberta producers who buy forage bales from out of province should be
on the lookout for unwanted guests.
Norway rats might be hitching a ride in the bales.
“The movement of feed from Saskatchewan and Manitoba into Alberta
usually prompts several questions regarding Norway rats,” said John
Bourne, a vertebrate pest specialist with Alberta Agriculture.
While it is a problem in all provinces, the issue is of particular
concern in Alberta, which is rat-free, unlike Saskatchewan and Manitoba.
Read Also
Interest in biological crop inputs continues to grow
It was only a few years ago that interest in alternative methods such as biologicals to boost a crop’s nutrient…
Bourne said it is likely that a live rat could be delivered into the
province, and the higher the volume of feed being imported, the greater
the risk.
The type of feed is a factor, because rats prefer green feed bales and
straw bales more than hay bales.
“Rats usually burrow into bales and are not easily detected,” he
said.”Nonetheless, there should be some sign of their presence.”
Bourne said rats leave telltale signs:
- Droppings – Rats produce 25 to 40 droppings per day so there should
be droppings even if the rats have travelled only a single day. Fresh
droppings are conspicuously large, measuring up to two centimetres long
and nearly 1/2 cm in diameter, are black or dark coloured, and are
blunt or round at both ends.
- Chewing – Rats can chew through almost any material, but in feed
bales their holes are obvious and will appear almost perfectly round,
measuring at least 5 cm in diameter. Field mice also burrow into bales,
but their holes are much smaller.
- Appearance – An adult Norway rat measures between 18 and 23 cm long
from nose tip to base of tail. A male adult can weigh up to half a
kilogram; females slightly less. The tail is usually about 13 to 18 cm
long, never as long as its body.
The distinctive tail is a dead giveaway. It’s cylindrically shaped like
a rope, is hairless except for short bristles and is tapered from base
to tip. A muskrat has a long tail but is flat along the sides and has a
ridge along the top for swimming, much different than a Norway rat.
Rats are tan to brown with black hairs throughout on top and buff or
creamy colouring underneath.
They have delicate, small front and hind feet that are pink. The feet’s
upper sides are covered with fine white or creamy hair. They have short
claws. Pocket gophers, ground squirrels and muskrats have much larger
feet that are generally darker and have darker hair on the upper sides.
In Alberta, collect any physical evidence if a rat or a suspicious
rodent is found on board a load of feed. Preserve it by placing it in a
plastic bag inside a solid container, such as an ice cream pail, and
freeze it so that it can be properly identified.
Call the local Alberta municipal fieldman for further information or
assistance.
