I recently attended a forestry conference where Doug Freedman of Harrisburg, Oregon was speaking. He is the owner of RCO Inc., a company that deals with varmint problems on an industrial scale. Here are some of the notes that were taken at his presentation: You start doing some of the math on the breeding numbers these guys could produce and it is flat scary. (Please note that if errors exist, it is due to my rapid note taking rather than a lapse by Mr. Freedman, who is an expert in his field. )
Tunnels: are 80-800 feet long-random in direction and consists of main and lateral tunnels. They make 2-to-3 mounds per day-moving two tons of soil per year.
Food: 3-5 food caches per tunnel system. They like tuberous plants ( particularly thistle he said ). They introduce their own habitat ( i am assuming ala war of the worlds )
Life cycle: multiple litters per year breeding starts in March and June. 19 day gestational period with 3-to-7 per litter. Mature dependency from adults in 40 days. Sexually mature in 1 year and they live 2-5 years.
Traps: control and trap both directions and place in main tunnels. Can use mouse traps on incline with strings tied to them. They patrol their tunnels 2-3 times per day ( very territorial ) if they see light they will investigate why a tunnel is opened.
Baits: Bait only main tunnels use strychnine and PREMIUM grade oats. Higher quality oats and freshness = palatability.
Control: remove forbes with tap roots
Habitat: Live above or below . Like a 14" canopy of grass golf ball sized holes. Can burrow 5-6 feet. Groups of 7-8 rodents nest together in winter
Food: tend to girdle seedlings and small trees. also may eat some grass ( unsure on this one )
Life cycle: 19 day gestational period. They have 6-to-7 litters per year. Can re-breed in 20 hours.
Control: cut grass below 10"
Baits: Zinc Phosphate.
Damage: They can carry the Plague. Forage on grain crops. Holes damage farm machinery. Have been known to damage dikes.
Habitat: Live above and below ground tunnels 15 feet long
Food Grass and grains
Life cycle: 1 litter per year usually 5 per litter
Baits: strychnine. Below ground only. Bait in summer to late fall. Place unpoisoned grain in an area to get them used to feeding in a spot. Then place the poison and get the whole family. can trap and shoot also can fumigate. Some have tried the ol propane wand and suffocation. Others have tried to ignite the burrows (Not suggested ).
Thanks Much, - E.B. in N. Idaho