Controlling Rats and Mice in Texas

Introduction: In order to effectively prevent or control rodent infestations, one must first learn to identify the different species common to a particular area of interest and become familiar with their behavior and habits. A thorough inspection of the area can then be conducted to look for and document signs of an infestation, to identify any specific problem species, and to estimate their populations. A control program employing appropriate rodent control tools, and techniques tailored to the infestation site, and to the specific rodent populations found, can then be implemented. Evaluating the results achieved, and making any improvements deemed necessary to the control program is a recommended final step in the process. Keep in mind, however, that results cannot always be measured by counting dead rats and mice. When baits are no longer being eaten, when there are no fresh droppings, and when no live rats or mice are seen, results are as good as can be expected.

Rats and mice are objectionable to humans in many ways: • They consume and contaminate (through their droppings) an estimated 20% of the world’s food supply. • They damage and destroy property, such as wood doors, floors, walls, clothing, furniture, and food containers. They chew on electrical wires (causing fires), undermine buildings, gnaw pipes, chew water hoses, and cut through mortar and cement. Burrowing rats may undermine building foundations and slabs. • They carry and/or spread diseases that are serious health hazards to both humans and domestic animals, including Salmonellosis (food poisoning), Swine Dysentery, Leptospirosis, Rickettsialpox, Trichinosis, Infectious Jaundice, Lymphocytic Choriomeningitis (LCM), and Rat Bite Fever. They also carry fleas, ticks and other ectoparasites, which potentially spread other diseases, such as typhus, bubonic plague and rat mite dermatitis. In May 1993, a previously unknown disease, Hantavirus Pulmonary Syndrome (HPS), associated with exposure to wild rodents, was identified among residents of the southwestern United States, and was subsequently recognized throughout the Americas. Through May 9, 2006, 438 cases have been reported in the United States, with a case fatality rate of 36%. • Their presence causes a great deal of anxiety for the occupants (people and pets) of infested homes and businesses. An infested food facility, for instance, would be at risk for poor inspection scores, fines, disgruntled employees, unhappy customers, and lost business.

All rat and mice species currently found in the United States may be classified as commensal (living with humans and dependent on them), or feral (in the wild state and human independent). For the most part, commensal rodents are nonnative species introduced from other parts of the world, and feral rodents are native to the Western Hemisphere (New World rodents), but there are some exceptions both ways. By far, commensal rodents present the greatest problem to man, and as such, will be emphasized in this instructional exposition. Commensal Rodents: Commensal is defined as “sharing one’s table”. Commensal rodents, which include Norway rats (Rattus norvegicus), roof rats (Rattus rattus), and Common House Mice (Mus musculus) have long been the unwelcome associates of humans. They followed human occupation and development of new countries and are now present in most parts of the world. In contrast to native rats and mice, they are aliens in North America, but are now very well established. They live with or very close to humans in homes, farms, ranches, buildings, grain storage facilities, sheds, garages, and structures of all kinds. Norway Rat: Rattus norvegicus (a commensal, nonnative species thought to originate from northern China) – also known as Barn Rat, Brown Rat, Gray Rat, Common Rat, House Rat, Norwegian Rat, Sewer Rat, Warf Rat, and Water Rat. This is the famous “Sewer Rat” in New York City. The Norway Rat is one of the best-known and most common rats. It is also one of the largest and most aggressive. It didn’t originate from Norway, but most likely owes its name to an 18th century English author, John Berkenhour, who mistakenly believed that the rat migrated to England from Norwegian ships in 1728. Physical Description: Norway Rat. • Adult Weight – 10 to17 ounces. • Adult Length – 13 to 18½ inches including tail (7 to 10 inches for head and body only). • Color – Usually grayish-brown but could vary between reddish-brown and completely black. White underside. • Body – Large, robust, and stocky with coarse shaggy fur. • Tail – 6 to 8½ inches long for adults (shorter than head and body), dark above, pale below, furless, and scaly. • Hind Foot Length/Track – Adults average slightly more than 1¾ inch. • Ears – Small, close to body – won’t cover eyes if bent forward. Rat has acute hearing, sensitive to ultrasound. • Eyes – Small. Rat is colorblind with poor eyesight – primarily sees light, shadow, and movement. • Nose – Blunt, acute sense of smell.

• Whiskers/body guard hairs – Sense walls, surfaces, and air movements for guideance during nocturnal travels. • Teeth – 1/8 inch gnaw pattern. Gnaws holes 2 inches or more in diameter with rough edges. Can gnaw through wood, lead, aluminum, copper, cinder block, or uncured concrete. Distribution: Widespread in the United States and most of the urban and agricultural areas of Canada due to its excellent adaptability. Best suited for temperate zones. Lives wherever humans live, particularly in urban areas. Habits: Commensual, nocturnal, burrows extensively, excellent swimmer, good climber, smart, and shy. Feeding and most activity occurs ½ hour after sunset until ½ hour before sunrise. Norway Rats build their nests in low or subsurface places and line them with soft material (such as shredded paper, cloth, grass, or other fibrous material), chewed into small pieces. They can burrow under sidewalks and foundation walls, or they can live in sewers, basements, cellars, and the lower portions of buildings. They explore their territory of 100 to 300 feet daily and are suspicious of any changes to this environment, including new foods. For this reason, it may take a couple of days for traps or poison baits to be effective. Norway Rats can also exist in the feral state where vegetation is tall and rank and affords adequate protection. The marshy lands on Galveston Island off the coast of Texas offer an ideal habitat for them. Norway Rats live in colonies and have a very strong social hierarchy – the biggest and strongest get the best food and harborages (places to hide and nest). Food and Consumption: Omnivores – prefers cereal grains but eats almost any human food including meats, fish, nuts, flour, fruits, vegetables, and eggs. Norway Rats visit fewer food sites than mice do, but eat more at each site. Requires ¾ to 1 ounce of food and ½ to 1 ounce of water each day. Biology and Reproduction: Norway Rats are prolific breeders. After giving birth, females can be in heat and become pregnant again in as little as 24 to 48 hours (and still lactate to feed their current litter of pups). Their relatively short life spans, short gestational periods, and rapid sexual maturity make effective rodent control critical. The reproductive cycle and number of rodent offspring increases with adequate food, water, and harborage. They will reproduce year-round in stable environments. • Gestation Period – 21 to 23 days. • Litter Size – 8 to12 pups. • Litter Number – 4 to 7 per year (heavier in spring and fall). • Growth – Eyes open in 14 to 17 days – weaned in 3 to 4 weeks – reach reproductive maturity in 8 to 12 weeks. • Droppings – ¾ inch or less in length with blunt/rounded ends (capsule shaped) – 30 to 180 pellets per day – soft and dark in color when fresh.

• Life Span – 1 to 3 years, but predators and intraspecific conflict limit most to about 1 year. More Norway Rat Facts: • They can gnaw their way through openings as small as ½ inch. • They can survive a fall from up to 25 feet onto a hard surface. • They can swim up to 1 mile. • They often kill and partially eat House Mice. This rat behavior is known as muricide. • They are hosts for the Seoul virus, which causes a mild form of Hemorrhagic Fever with Renal Syndrome (HFRS). Evidence of Seoul virus infection has been found in Norway Rats throughout the world, including the United States, but human disease associated it has been restricted to Asia. Norway Rats are not known to be carriers of hantavirus. Roof Rat: Rattus rattus (a commensal, nonnative species originating from tropical Asia) – also known as Alexandrian Rat, Asian Black Rat, Black Rat, Fruit Rat, Ship Rat, and Tree Rat. The Roof Rat is smaller, slimmer, and more agile than the Norway Rat. It is a better climber but a poorer swimmer. Indications are that the larger and more aggressive Norway Rat is supplanting the Roof Rat in many of the cooler regions of the United States. In the South, however, the Roof Rat is by far the more common of the two. Physical Description: • Adult Weight – 6 to 12 ounces. • Adult Length – 14 to 18 inches including tail (6½ to 8 inches for head and body only). • Color – Varies from black to brownish-gray with a pale yellow or grayish-white underside. • Body – Sleek, acrobatic, and graceful with smooth fur. • Tail – 7½ to10 inches long for adults (longer than the head and body) – uniform color, furless and scaly. • Hind Foot Length/Track – Adults average slightly less than 1½ inch. • Ears – Large. Cover the eyes if bent forward. • Eyes – Large and prominent. Rat is colorblind with poor eyesight – mainly sees light, shadow, and movement. • Nose – Pointed, acute sense of smell. • Whiskers/body guard hairs – Sense walls, surfaces, and air movements for guideance during nocturnal travels. • Teeth – 1/8 inch gnaw pattern. Gnaws holes 2 inches or more in diameter with rough edges. Can gnaw through wood, lead, aluminum, copper, cinder block, or uncured concrete.

Distribution: Best suited and largely confined to warmer areas. In the United States they are found along the Pacific Coast, the lower half of the Atlantic coast, throughout Texas and the other Southern Gulf States, along major river systems (i.e. Mississippi River), and in Hawaii. They are more common than Norway Rats in these areas and are especially prevalent in towns and marine ports. They are also found in some parts of coastal southern Canada. Habits: Commensual, nocturnal, acrobatic (able to swing, jump, and climb), seldom burrows, smart, and shy. Feeding and most activity occurs ½ hour after sunset until ½ hour before sunrise. The Roof Rat prefers to nest in locations off the ground – in attics or in the upper portions of buildings (where they tear up insulation materials to build their nests), and in trees, overgrown shrubbery, and vines. When frightened, it tends to flee upwards. It makes typical runways (paths between feeding and harborage areas) along rafters, crossbeams, pipes, electrical wiring, up and down studding, and along horizontal ceiling joists, often leaving rub marks (dark-colored layers of grease and dirt) to mark its travel way. Roof Rats explore their territory of 100 to 300 feet daily, and are very suspicious (more so than Norway Rats) of any changes to this environment, including new foods. For this reason, it may take a couple of days for traps or poison baits to be effective. They seldom become established in the wild as feral animals. Roof Rats have a strong social hierarchy. Food and Consumption: Omnivores with a preference for seeds, fruits, nuts, berries, vegetables, slugs, and snails, but will also eat eggs, meat, and grain products. Roof Rats visit fewer food sites than mice do, but eat more at each site. Requires ½ to 1 ounce of food and 1 ounce of water each day. Biology and Reproduction: Roof Rats are prolific breeders. After giving birth, females can be in heat and become pregnant again in as little as 24 to 48 hours (and still lactate to feed their current litter of pups). Their relatively short life spans, short gestational periods, and rapid sexual maturity make effective rodent control critical. The reproductive cycle and number of rodent offspring increases with adequate food, water, and harborage. They will reproduce year-round in stable environments. • Gestation Period – 21 to 23 days. • Litter Size – 4 to 8 pups. • Litter Number – 4 to 6 per year (heavier in winter to spring). • Growth – Eyes open in 14 to 17 days – weaned in 3 to 4 weeks – reproductive maturity reached in 8 to 12 weeks. • Droppings – ½ inch or less in length with pointed ends (spindle shaped) – 30 to 180 pellets per day – soft and dark in color when fresh. • Life Span – 1 to 3 years (most are limited to about a year).

More Roof Rat Facts: • They can gnaw their way through openings as small as ½ inch. • They can survive a fall from up to 25 feet. • They often kill and partially eat House Mice. This rat behavior is known as muricide. • Roof Rats are not known to be carriers of hantavirus. House Mouse: Mus musculus (a commensal, nonnative species originating from Asia, likely Northern India) – also known as Common House Mouse and Domestic House Mouse. The House Mouse is believed to be the second most populous mammalian species on earth, after Homo sapiens. They are highly adapted to human environments and can thrive under a variety of conditions. Physical Description: House Mouse: • Adult Weight – 5/8 to 1 ounce. • Adult Length – 5 to 7 ½ inches including tail (2 to 3 ½ inches for head and body only). • Color – Grayish-brown with a light cream underside. • Body – Small, pear-shaped, and slender with short hair. • Tail – 3 to 4 inches long for adults (longer than head and body combined), furless and scaly. • Hind Foot Length/Track – Adults average slightly less than ¾ inch. • Ears – Relatively large with little hair. Hears very well in both the sonic and ultrasonic ranges. • Eyes – Small and somewhat protruding. Mouse is colorblind and cannot recognize objects over 10 feet away. • Nose – Highly developed sense of smell. • Whiskers/body guard hairs – Sense walls, surfaces, and air movements for guideance during nocturnal travels. • Teeth – Gnaw pattern is less than 1/16 inch. Gnaws 1½ inch diameter clean cut holes. Distribution: Widespread throughout Texas and the United States, particularly in human dwellings and out buildings. Also found in southwest Canada, north to central British Columbia, and along the Pacific coast to Alaska. Habits: Commensal, nocturnal, good jumpers, excellent climbers, able to swim, dumb, and curious. Getting House Mice in one’s house is very common. They particularly like to come inside during the cold winter months. They do not like bright lights – feeding and most activity occurs ½ hour after sunset until ½ hour before sunrise. They can be found in and around homes, farms, granaries, feed houses, stores, outbuildings, at or below ground level in cultivated fields, and even on all floors of the tallest skyscrapers. Where conditions permit, they

© 2014 All Star Training, Inc. 6 can also exist in the feral state – in fields, along watercourses, and other places where vegetation is dense enough to afford concealment. They are often found in the vegetation along irrigation ditches, sometimes sharing common runways with native mice. Along the Rio Grande in Texas, patches of cane are often honeycombed with their runways. They explore their limited home range of 10 to 30 feet daily to examine any newly introduced objects. They have a strong social hierarchy and are territorial – one dominant male usually lives with several females and their young. Food and Consumption: Omnivores – feed on practically any type of food suitable for man or beast. They prefer seeds but also eat cereal grains, fruits, vegetables, meats and dairy products. In the feral state, they feed on insects and a variety of plant material, including seeds, green stems, leaves, and Alfalfa hay. Mice frequent many feeding sites (often 20 to 30) during their active period, eating small amounts of food at each site. Their daily food consumption is 1/10 ounce. Water is not essential to their survival if their food contains at least 16 percent moisture. Biology & Reproduction: House Mice are exceedingly prolific breeders. After giving birth, females can be in heat and become pregnant again in as little as 24 to 48 hours (and still lactate to feed their current litter of pups). Their relatively short life spans, short gestational periods, and rapid sexual maturity make effective rodent control critical. The reproductive cycle and number of rodent offspring increases with adequate food, water, and harborage. They will reproduce year-round in stable environments. • Gestation Period – 19 to 21 days. • Litter Size – 4 to 7 pups. • Litter Number – 5 to 13 per year, averaging about 8 per lifetime. • Growth – Eyes open in 7 to 14 days – weaned in 3 to 4 weeks – reach reproductive maturity in 5 to 8 weeks. • Droppings – ¼ inch or less in length with pointed ends – 50 to 75 pellets per day – soft and dark in color when fresh. • Life Span – 1 year (less in the wild due to predators and harsh environments) – 2 to 3 years in protected environments. More House Mouse Facts: • They can gnaw through openings as small as ¼ inch, and can squeeze through openings as small as a dime. • They can survive an 8-foot fall onto a hard surface. • They can travel at 9 to 12 feet per second (6 to 8 mph) over short distances. • They stand only on the hind legs supported by the tail when eating, fighting, or orienting themselves. • It is thought that House Mice were the primary reason for the taming of the domestic cat.

• They are afraid of rats, which often kill and partially eat them. • House mice are not known to be carriers of hantavirus. Feral Rodents: All hantaviruses known to cause HPS are carried by New World (native) rats and mice, family Muridae, subfamily Sigmodontinae. This subfamily contains at least 430 species of rats and mice, which are widespread in North and South America. These wild rodents are not generally associated with urban environments, but some species will enter human habitation in rural and suburban areas. Several hantaviruses that are pathogenic for humans have been identified in the United States. In general, each virus has a single primary rodent host. Wild rodents carrying the types of hantavirus that cause HPS in the United States include Deer Mice (Peromyscus maniculatus), Cotton Rats (Sigmodon hispidus), Rice Rats (Oryzomys palustris), and White-Footed Mice (Peromyscus leucopus). Deer Mouse: Peromyscus maniculatus (a feral, native species) • The adult Deer Mouse is a small white-footed rodent with big eyes and prominent leaf-like ears. Its head and body are normally 2 to 3 inches long, and its tail adds another 2 to 3 inches. You may see it in a variety of colors, from gray to reddish brown, depending on its age. The underbelly is always white and the tail is sharply bicolor – white beneath and dark above. • It looks a lot like the White-Footed Mouse, and is easily and often confused with it. The Deer Mouse has a more hairy, somewhat shorter, and more sharply bicolor tail, a longer pelage, and it often has whitish tufts of hair at the base of the ears that the White-Footed Mouse lacks. • It is common and widespread in rural areas throughout much of North America. In Texas, it is statewide, but uncommon in the eastern, coastal, and southern parts of the state. • They are a native, feral species but will enter human habitation in rural and suburban areas. Deer Mice habitats include woodlands, grasslands, areas of open brush, and even sparsely vegetated desert areas, living in burrows, brush piles, and rock crevices. Their nests are hollow balls of dry grass, shredded weed stems, and other available material, such as rabbit fur and bird feathers. They are nocturnal and they do not hibernate. • Their food consists chiefly of seeds, in-season fruits, bark, roots, and herbage. • These mice breed year-round and tend to overpopulate in favorable habitats, becoming troublesome. Large populations and a high tolerance to a variety of habitat conditions make control difficult and expensive. Small carnivores, owls, and snakes can help keep their populations in check. • Deer Mice are host reservoirs for the Sin Nombre Virus (SNV), the primary causative agent of HPS in the United States.

Cotton Rats: Sigmodon hispidus (a feral, native species) • The Cotton Rat is a moderately large and robust rodent with small ears. Its head and body are normally 5 to 7 inches long, and its tail adds another 3 to 4 inches. The hair is long and course and the color is grayish brown to grayish black. • It is found in the southeastern United States, west to Kansas and Nebraska (including most of Texas and Oklahoma and parts of southern New Mexico and southeastern Arizona), and in Central and South America. • They are a feral, native species, preferring overgrown areas with shrubs and tall grasses. In west Texas (where grassy ground cover is not available), they live in dens at the bases of small, low mesquite clumps. They place their nests, made of cotton (hence the name), shredded grasses and leaves, in chambers off underground burrows, or above ground in dense clusters of grass, piles of brush, or other situations that offer concealment and protection. • Their food is almost exclusively plant material, but there is some evidence that they feed on the eggs of ground nesting birds, such as bobwhites and meadowlarks. They are active the year round and do not store food for winter use. • Cotton Rat populations are subject to violent fluctuations, being correlated with the amount of suitable habitat available in a particular area, which in turn is correlated with the amount of rainfall. The last serious outbreak in Texas occurred in 1958, and caused serious losses (as much as 90% in some cases) to farm crops – particularly, peas, peanuts, watermelons, and cauliflower. Another severe outbreak occurred in 1919, and in fact, peak populations are recorded about every 10 years in central Texas. Fortunately, every eruption is followed by a crash. Predators such as coyotes, bobcats, hawks, owls, and certain snakes take their toll, but the main killer is disease – as the rats increase in numbers, there are more contacts for the rapid spread of disease. • Cotton Rats are host reservoirs for the Black Creek Canal Virus, a form of HPS. Rice Rats: Oryzomys palustris (a feral, native species) • The Rice Rat is slightly smaller than the Cotton Rat, having a head and body 5 to 6 inches long and a very long 4 to 7 inch tail. Its ears are short and hairy and it sports short, soft, grayish brown fur on top, a gray or tawny (light brown to reddish brown) underbelly, and white feet. • It is found in the southeastern United States, in coastal eastern Texas (west to Brazos County and south to Cameron County), north to southern Kansas and Missouri, and in Central America. • They are a feral, native species, and are semi-aquatic, preferring marshy areas. In southeastern Texas, they are common on dykes and levees thrown up in coastal marshes. Their globular nests are composed of

grasses, sedges, or weeds, and are frequently placed under debris above high water in emergent vegetation. They occasionally take over and remodel blackbird nests. • Marsh Rice Rats are omnivorous, consuming about equal amounts of plant and animal foods, including green vegetation, fungus, sedge seeds, marsh grasses, rice (hence the name), insects, fiddler crabs, snails, fish, and the carcasses of small rodents and birds. • In most places, these rats do no damage, but in rice fields they may become economically important by consuming large quantities of rice. • Rice Rats are reservoir hosts for the Bayou Virus, a form of HPS. White-Footed Mouse: Peromyscus leucopus (a feral, native species) • The White-Footed Mouse is slightly larger than the Deer Mouse and is hard to distinguish from it. The head and body together are about 4 inches long, and its bi-coloured tail (shorter than the head and body) adds another 2 to 4 inches. Topside, its fur ranges from pale brown to reddish brown, while its underside and feet are white. • The White-Footed Mouse is found throughout most of the eastern and central United States, excluding northern Maine, portions of the southern coastal regions of North Carolina, South Carolina, Georgia, Alabama, Mississippi, Louisiana, and Texas, and all of Florida. In the West, it is present in eastern Montana, northeastern Wyoming, southeastern Colorado, all but northwestern New Mexico, and southeastern and central Arizona. It is also found in Mexico. • They are a native, feral species, but will enter human habitation in rural and suburban areas. Primarily, they live in wooded and brushy areas, but will sometimes live on ground that is more open. In east central Texas, White-Footed mice are most abundant in bottomlands, less so in post oak uplands, and almost completely absent from prairie lands. They are adept at climbing, and often den in hollow trees and in old bird or squirrel nests – out of danger from floodwaters. In areas not subject to inundation, they live in dens under logs, in stumps, brush piles, burrows, or buildings. • Their diet consists chiefly of seeds, nuts, acorns, and pecans. In spring and summer, they feed to some extent on fruits, insects, snails, and other invertebrates. When food is abundant, they store it in and about their nests for winter use. • They need to be controlled if they become too numerous in a particular area and become destructive of stored and shocked grains. In most places, however, they are of little or no economic significance because of natural predators such as owls, snakes, and weasels. • White-Footed Mice are reservoir hosts for the New York Virus, a form of HPS.

The Inspection Process: Conduct a thorough inspection in the particular area of interest to look for and document signs of an infestation. This knowledge is used to identify the specific problem species and to estimate their populations. Rodents behave predictably, leaving many clues that inspectors can follow to determine if a rodent infestation exits, and if it does, to gauge its intensity. The following tools will be useful in the inspection process and should be assembled before starting. Recommended Inspection Tools: • Flashlight (with strong beam) to find rodents and their signs in dark areas. • Black light to identify rodent urine. • Knife or spatula to test age of droppings and to remove them from under objects for identification. • Specimen container to collect unknown specimens. • Protective gloves to protect yourself from diseases carried by rodents. • Knee pads to protect your knees from sharp objects on floors and in crawl spaces. • Binoculars to make it easier to see what you can’t get close to. • Respirator with HEPA filter to prevent inhaling dust, which may be contaminated with disease organisms. • Hand sanitizer (over 60% alcohol) to kill bacteria when soap and water are not available. • Clipboard, graph paper, inspection checklist, and pencil to diagram building(s), take notes, and to act as a reminder to inspect critical areas. A Sample Inspection Form is presented on the following page. What to Look For: • Droppings and urine are left wherever rodents travel or rest, especially in corners. Identify the rodent type by the size and shape of droppings found, and use a palette knife to check them – fresh droppings are soft and shiny, while older droppings are gray, crusted, and easy to break. Look for urine stains using a black or ultraviolet light to make them more visible, and check for a distinctive musky odor. One can usually smell the presence of rats and mice, especially in poorly ventilated rooms. • Footprints and tail drags may be seen in the moist earth or in dusty places. Norway Rats and Roof Rats will leave a hind foot track measuring approximately 1½ to 1¾ inches, whereas a House Mouse’s track is 3/4 inch or less. The rats will also drag their tails, leaving a mark between their feet tracks. To view difficult-to-see tracks, shine a strong flashlight at a low angle across the dust. A non-toxic tracking powder, such as unscented baby powder or a mason’s chalk line, lightly sprinkled on a suspected rodent trail, and re-inspected the following day, may also assist in identifying tracks.

• Look for burrows beneath foundations, gardens, compost piles, rubbish, shrubbery, and in haystacks or baled hay. If the burrow is active, it is usually clear of vegetation. Look for nests in woodpiles and in garages behind boxes or in drawers. Look for signs of runways in the grass or through trash. Rodents memorize their territory through kinesthetic (muscle) memory and use the same paths repeatedly, preferring to move along objects. Identifying rodent movement patterns helps to effectively place traps and bait stations. • There may be signs of gnawing and “greasy smear” rub marks. Fresh gnaw marks are light and will darken over time. Scratch-like gnaw marks, approximately 1/16-inch, are made by mice. Clear 1/8 inch gnaw marks are made by rats. Rodents leave rub marks from body oil, grease, and dirt along their runways wherever their bodies have touched walls or rafters. New rub marks will smear. Old rub marks are darker and may flake off. • Listen for rodent noises just after dusk and be aware of upset pets. House pets such as cats and dogs, may become agitated when they hear rodents gnawing, digging, running, fighting, or squealing. Degree of Infestation: Heavy, Moderate, or Low can be gauged as follows: • Droppings – Numerous or just a few? Scattered or everywhere? Fresh or old? • Smears – Faintly seen or very heavy and greasy? • Runways – Seldom used or worn smooth by the passage of many rodents? • Feeding signs – A solitary rodent may be quite neat about his feeding. If many feed, they may fight between themselves and scatter food. • Sounds – Mice squeal continually in their nests. Rats make running and squealing noises even when not alarmed. Rodent activity increases after dark, which is the best time to listen for them. Methods of Control: Experience has shown that it is best (less time consuming) to control rodents before their numbers get to high. An integrated control program using rodenticides and traps, removal of shelter, food and water, and rodent proofing is most effective. Rodenticides: There are many different kinds of rodenticides available. Most are anticoagulants, which are preferred by rodent control professionals, and cause death by internal bleeding (they inhibit the blood clotting mechanism). Anticoagulant rodenticides are available in ready-to-use forms at farm and ranch supply stores, nurseries, and grocery stores in either the modern single-dose or the older multiple-dose formulations. Single- dose baits cause death when eaten once, and are effective within several days. Multiple-dose baits must be eaten every day for 5 or 6 days or every other day for 12 days before hemorrhages are fatal. Neophobia, the fear of new objects, makes rats extremely nervous about changes in their territory. It takes several days for them to

accept new objects in their environment, including bait stations. The delayed effects of anticoagulants help reduce bait shyness. Since rodents feel no pain, there is no warning, and they continue to feed if the bait is attractive. Rats and mice normally begin dying anywhere from 3 to 10 days after feeding on the baits. Product configurations for these rodenticides include cereal grains, mini-blocks, paraffin all-weather blocks, paraffin pellets/place packs, and tracking powders that adhere to rodents’ feet and fur (ingested during grooming). A water-soluble bait is also available. For rat control, offer them dry anticoagulant baits in ¼ to ½ pound packages. Place packages less than 25 feet apart where rats feed along walls, inside and outside of buildings, in dark corners, under floors, in attics, and under stairways. To hurry feeding, cut packages so that bait spills out. When anticoagulant bait becomes old, replace with fresh bait, and keep replenishing until rats stop feeding. Water-soluble bait is particularly effective in dry surroundings, and where there is already another food available. For mouse control, place tablespoon amounts (¼ to ½ ounces) of dry anticoagulant bait at 8 to 12 foot intervals where mice travel. Water-soluble bait is not effective on mice because they require very little water. Proper placement of baits can be as important as the type of bait used, or more so. Place all baits in rodent travel ways or near their burrows and harborages. Do not expect rats or mice to go out of their way to feed on the baits, although they do occasionally. The best idea is to locate the bait where it will be in the rodents' normal line of travel. Although rodenticides are generally safe to use, care should be taken in placing them so that neither people nor domestic animals have access to them. Containers known as bait boxes/stations can be purchased or constructed for the dual purpose of protecting baits from the elements and restricting bait access to mainly rodents. These boxes provide an excellent safeguard for non-target people, pets, and livestock while providing rodents with a comfortable place, from their perspective, to feed and groom. Label all bait stations clearly with appropriate warnings. Humans who accidentally ingest anticoagulant bait should be forced to vomit – give them a tablespoon of salt in a glass of warm water and immediately contact a physician or poison control center. The antidote usually prescribed for human or non-target animal anticoagulant poisoning is Vitamin K1. Bait labels provide directions for bait use as well as information useful to doctors should an accidental poisoning occur. These labels should always be read and followed exactly. All unused bait and containers should be destroyed (by burning or burying them deeply), or stored out of the reach of children and pets. Some professionals discourage the use of store-bought baits because they are typically not stored or used properly, and there is no way to control where the critters die.

Traps: Traps are just as effective as rodenticides, but require more skill and labor. Snap traps, cage traps and glue boards are recommended in sensitive areas, such as homes, schools, and hospitals, where the use of rodenticides is inadvisable, and in places where there are few rats and mice. Traps have several advantages over rodenticides: • They are pesticide free and safer than the potentially hazardous baits. • Results are quick and immediately viewable. • They are more versatile. They can be placed in a varierty of settings and can be used over and over again. • Dead rodent disposal is fast and easy. There are no odor problems from rodents dying in inaccessible areas. Use a variety of fresh baits on successive traps, rather than a single kind, and change baits daily. Fruit, peanut butter, bacon, and nuts all make excellent choices. Traps should be set behind objects, in dark places, and along travel routes where rodent signs are evident. They should be placed no more than 10 feet apart in areas where mice are active. Glue boards and cage traps should be placed parallel to the base of a wall. Snap traps should be set perpendicular, in such a manner that the rodent will pass directly over the trigger when following its natural route. To make the trap more effective, a 2-inch by 2-inch piece of cardboard can be attached to expand the trigger. Sanitation – Removal of Shelter, Food, and Water Supply: Rodents have three basic requirements – food, water, and harborage. If one or more of these items is missing from an area, rodent populations will remain low. The following control procedures are recommended, on a continuous basis, for both the interior and exterior of buildings. • Eliminate debris that can serve as harborage for rodents. Promptly dispose of trash accumulations, such as empty boxes and cartons, and stack other items like lumber, pipes, gardening equipment, and storage crates and boxes, at least 8 inches off the ground and at least 1 foot from vertical walls. Store firewood outside, as far from the house as possible. • Trim weeds and brush and keep grass cut short to minimize cover and food sources around building perimeters. • Clean up food waste and spillage daily. Dispose of waste and garbage in tightly covered metal cans placed at least 18 inches off the ground. • Store foodstuffs at least 18 inches off the floor and wall in rodent-proof containers, such as glass or metal. • Between storage areas, allow 24-inch aisles for easier inspection and sanitation.

• Mend leaky faucets and do away with water storage areas that rodents can access. • Screen dumpster drainage holes with hardware cloth. • Don’t leave pet food out overnight and clean bird feeders daily. Methods of Control / Removal of Food and Water Supply: Exclusion – Mouse and Rat Proofing: The most successful and longest lasting form of rodent control in homes and buildings is to prevent them from getting inside. Attempt to seal up all openings through which mice, the smallest of the rodent pests, can enter, which includes all that are larger than ¼ inch. Specific steps include, but are not limited to, the following: • Repair cracks in foundations with liquid concrete or other auitable foundation repair material. • Cover or seal all openings around water pipes, cables, electrical wires, sewer pipes, drain spouts, and vents that enter through walls, or through the foundation, with rodent-resistant materials, such as copper mesh, hardware cloth, or steel wool, and then fill with caulk (for openings up to ¼ inch), or with expanding foam (for openings larger than ¼ inch). • Repair or replace damaged ventilation screens around the foundation and under eaves. Screen all windows that can be opened and make sure they are in good condition. Inspect internal screens on roof and attic air vents and replace or repair as necessary. Cover rooftop plumbing vent pipes in excess of 2 inches in diameter with screens over their tops. • Cover all chimneys with a spark aresster. • Make sure that all exterior doors, including garage doors, are tight fitting, sealed, and weather proofed at the bottom. Provide tight fitting covers for crawl spaces. • Install self-closing exits or screening to clothes dryer vents to the outside. • Remember that pet doors into the house or garage provide an easy entrance for rodents. • Close side doors to the garage when not in use, especially at night. • Cover all unnecessary openings with sheet metal or concrete. Sheet metal can also be used on door and window edges to prevent rodent gnawing, and concrete can be used to prevent rats from burrowing under foundations. Results: The results achieved from an integrated control program cannot always be measured by counting dead rats and mice. When baits are no longer being eaten, when there are no fresh droppings, and when no live rats or mice are seen, results are as good as can be expected.