Deer Mouse and White-Footed Mouse Q&A

Editor’s note: The following excerpt is from the recently published third edition of "The Vertebrate Pest Handbook: Questions & Answers on Norway Rats, Roof Rats, House Mice & Deer Mice." Though based on the second edition published in 1999, Vantassel has updated the information as well as narrowed the scope of content to cover only commensal rodents. The book teaches important concepts and facts about commensal rodents, disease, and control through a question-and-answer format. Question types include true and false, matching, and short answer. The book costs $23.95 post paid to the United States. I can be purchased from https://wildlifecontrolconsultant.com/store-3/ols/products/vertebrate-pest-handbook-3rd-ed and the e-book is available for $14.95 at https://www.lulu.com/shop/stephen-vantassel/vertebrate-pest-handbook-3rd-ed/ebook/product-rn64w5.html?q=vantassel&page=1&pageSize=4 

According to Stephen Vantassel, editor of the third edition "The Vertebrate Pest Handbook,” there hasn’t been enough attention on deer and white-footed mice in the pest control field, which he finds surprising considering how common the mice are in residences. Vantassel selected 11 questions from the short answer section of the Peromyscus chapter in the book.

Q: Can bait stations for control of deer mice be placed in trees?
A: Yes. (Assuming the label allows the rodenticide to be used in bait stations and for control of deer mice). Deer mice are good climbers and placement of stations in elevated areas can reduce rodenticide exposure to non-target animals. Just be sure the opening is reduced to 1½-inch (3.81 cm) diameter.

Q: Do male white-footed mice (Peromyscus leucopus) travel farther and more frequently to the edges of their home range than females?
A: Yes. A possible reason is the male is patrolling the area he controls.

Q: Do white-footed mice (Peromyscus leucopus) prefer denser plant undergrowth?
A: As one study found that white-footed mice were 19x more likely to be found in areas where the ground cover was heavy than where it was open.

Q: Are deer mice relatively tolerant of fellow deer mice?
A: Yes. Deer mice are fairly tolerant of each other regardless of age or sex. However, females in estrus will defend their territories and young.

Q: What seeds do Midwestern deer mice prefer?
A: In a choice test among seven options, deer mice were found to prefer the following seeds in order of preference: corn, soybeans, ragweed, foxtail, velvetleaf, lambsquarters, and cocklebur.

Q: What are some good baits to use in traps for Peromyscus spp.?
A: Creamy peanut butter, rolled oats, raisins, wild bird seed (without peanut shells), and mixtures of the above. (See Appendix concerning use of nut-based lures around those with allergies).

Q: How do you distinguish between male and female Peromyscus spp.?
A: Measure the distance between the anus and the sexual organ (nipples also signify female but aren’t always visible). In female adults, the vagina and anus are within ¼-inch (0.6 cm), and for adult males the distance between penis and anus is 0.4 inches (>1.0 cm). Other researchers use ≥ 0.16 inches (4mm) distance for male and shorter for females.

Q: How does one distinguish a juvenile, sub-adult and adult Peromyscus spp.?
A: While there isn’t necessarily a perfect way to determine mouse maturity, weight is 1 convenient method. Juveniles are <0.42 oz (<12 g), sub-adults weigh between 0.46-0.67 oz (13-19 g) and adults weigh >0.71 oz (>20 g). Others say that for deer mice, an adult is one that weighs ≥0.56 oz (≥16 g).

Q: Is it common for deer mice to be infected with bot flies?
A: While the parasite can cause significant harm to deer mice, some recover.

Q. How wide can a deer mouse open its mouth?
A: The maximum jaw opening for a deer mouse is estimated to be ½-inch (12.7 mm).

Q: Aside from bait and location, are there other reasons why a white-footed mouse would be attracted to a trap?
A: Adult white-footed mice are more attracted to traps that captured a member of the opposite sex. This was particularly true during mating periods. Juvenile mice were more attracted to traps that caught another juvenile. White-footed mice tended to avoid traps that caught a predator (e.g., shrew).