Vertebrate Pests

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Vertebrate Pests

• Rats, House Mice, Pocket Gophers, Ground
  Squirrels, Tree Squirrels, Moles, Rabbits and
  Bunnies, Deer, Pigeons, European Starlings, Etc.

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Rats

• There are two common rats in Southern California
• The roof rat (Rattus rattus)
• And the Norwegian rat (Rattus norvegicus)
• Rats are mostly nocturnal
• Poor eye sight is made up for with a keen sense
  hearing, smell, taste and touch

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Roof Rat

• Rattus rattus
• Smaller than Norway rats
• Sometimes called black rats
• Tails are longer than combined head and body
  length
• Agile climbers and good jumpers making them more
  difficult to exclude

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Roof Rat

• Nests are usually above ground in shrubs and
  trees, and dense vegetation
• In buildings they are found in enclosed, elevated
  spaces cabinets, attics, false ceilings, etc
• Roof rats tend to be found in the warmer more
  coastal regions

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Norwegian Rat
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Roof Rat
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Roof Rat Distribution
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Norway Rat

• Rattus norvegicus
• A.K.A. brown rats or sewer rats
• Stocky bodied
• Burrows along foundations, under debris piles,
  wood piles, or other moist areas
• Indoors usually found in basements or at the
  ground floor
• Found in all 48 contiguous states

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Norway Rat
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Norway Rat
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Rat Comparisons
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Rat Comparisons
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Rat Comparisons
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Dropping Comparison
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Spotting Infestations

• Droppings around dog or cat dishes or pet food
  storage containers
• Noises coming from the attic just after dusk
• Remnants of rat nests in firewood stacks

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Spotting Infestations

• Pets bringing home dead rat carcasses
• Evidence rodents are feeding on fruits and nuts
  that are in your yard or falling from the trees
  in your yard
• Burrows among plants or damaged vegetables when
  working in the garden

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Spotting Infestations

• Rats traveling along utility lines or on the tops
  of fences at dusk or soon after
• Rat nests behind boxes or in drawers in the
  garage
• Smudge marks caused by the rats rubbing their fur
  against beams, rafters, pipes, and walls

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Spotting Infestations

• Burrows beneath compost piles or beneath garbage
  cans
• Droppings in your recycling bins
• Drowned rats in swimming pools or hot tubs
• Evidence of something digging under garden tool
  sheds or doghouses

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Rat Management

• There three commonly used methods of controlling
  rat problems
• Sanitation
• Building construction and rodent proofing
• Population control trapping and toxic baits

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Sanitation

• Areas should be kept clear of trash and debris
• Food sources should be removed
• Pet food should never be left out over night
• Storage containers should be tightly sealed
• Reduce or remove overgrown vegetation

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Construction Rodent Proofing

• One of the most effective means of rodent control
  is exclusion build them out
• Seal all cracks or openings larger than 1/4
• Make certain doors, windows and screens fit
  securely

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Rodent-Proofing Your Home

• Repair or replace damaged ventilation screen
  around the foundation and under eaves
• Provide a tight fitting cover for the crawl space
  
• Seal all openings around pipes, cables, and wires
  that enter through walls or the foundation

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Rodent-Proofing Your Home

• Be sure all windows that can be opened are
  screened and that the screens are in good
  condition
• Cover all chimneys with a spark arrester
• Make sure internal screens on roof and attic air
  vents are in good repair

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Rodent-Proofing Your Home

• Cover rooftop plumbing vent pipes in excess of 2
  inches in diameter with screens over their tops
• Make sure all exterior doors are tight fitting
  and weatherproofed at the bottom
• Seal gaps beneath garage doors with a gasket or
  weather-stripping.

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Rodent-Proofing Your Home

• 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
• Keep side doors to the garage closed, especially
  at night

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Population Control

• Limiting food sources and habitat can be an
  effective means of control
• Periodically it becomes necessary to physically
  reduce the population
• Bait stations are an effective means of outdoor
  control
• Trapping is an effective means of indoor control

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Snap Traps

• Good for indoor use in and under cabinets,
  sheds, etc.
• Snap traps offer positive results
• They are relatively safe and effective

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Bait Stations

• Some are designed for indoor use
• Most are for outdoor use
• Toxic baits are put out of reach from other
  animals within the bait stations

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Bait Stations
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The House Mouse

• Mus musculus
• Highly troublesome pest nation wide
• Thrives under a variety of conditions
• Found in and around homes and commercial
  buildings, open fields and agricultural lands

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The House Mouse
Mus musculus House Mouse
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House Mice

• Capable of causing large amounts of damage
• Mice consume and contaminate human food supplies
  and animal and pet feed
• Mice can transmit pathogens
• They have not been found to transmit hantavirus

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House Mice

• Mice are small rodents
• Weight of about 1/2 ounce
• Color is light brown to gray
• 5-1/2 to 7-1/2 long including a 3 to 4 tail
• House mice are typically nocturnal

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Mouse Signs

• Mice infestations are typically recognized by
• Droppings
• Fresh gnaw marks
• Tracks
• Nests finely shredded paper and other fibrous
  materials
• Nests are typically found in secluded, sheltered
  areas

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House Mice

• House mice often live in close association to
  humans
• They are excellent climbers
• Capable of running up any rough vertical surface
• They can jump as high as 12
• And can squeeze through openings slightly larger
  than 1/4

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Prolific Little Rascals

• House mice can have 5 to 10 litters per year
• With 5 to 6 young per litter
• House mice reach reproductive maturity in 6 to 10
  weeks
• The average life span is 9 to 12 months

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Controls

• Sanitation
• Exclusion
• Trapping or baiting becomes necessary when
  infestations occur
• Snap traps or sticky traps
• Bait stations toxic baits

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Traps
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Hantavirus Vectors
White-Footed Mouse Peromyscus maniculatus
Deer Mouse Peromyscus leucopus
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Pocket Gophers

• Thomomys species
• 5 species occur in California
• Burrowing rodents
• Named for fur-lined external cheek pouches
• They are physically well equipped for digging and
  burrowing

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Pocket Gophers
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External Cheek Pouches
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Pocket Gophers

• Pocket gophers have short, fine brown furs that
  resists caking mud
• Small eyes and large ears
• Large incisor teeth
• 6 to 10 long
• Powerful front-quarters with large claws on front
  paws
• Well suited for digging

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Claws Teeth
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Gopher Habitat

• Pocket gophers are typically found underground
• Occasionally seen feeding aboveground or pushing
  soil from burrows
• Activity is indicated by large, crescent-shaped
  mounds of fresh soil
• The tunnel is plugged with soil
• The plug is offset from the center of the mound

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Pocket Gopher Mounds
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Tunnel Systems

• Tunnels appear regularly in irrigated areas
• Non-irrigated areas activity in fall spring
• Burrow systems can cover as much as 2,000 sq. ft.
• Tunnels 2-1/2 to 3-1/2 dia. 6 to 12 deep
• Nests and storage galleries as deep as 6
• Short, sloping tunnels connect tunnels to surface
  used to evacuate soil

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Tunnel Systems
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Pocket Gophers

• Do not hibernate
• Active at all hours
• Typically solitary except when breeding
• Reach sexual maturity in about 1 year
• Life span is about 3 years
• Females have up to 3 litter per year in irrigated
  areas
• Typically only 1 litter in non-irrigated areas
  fall - spring

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Feed Holes

• Feed holes are usually unplugged
• Vegetation is clipped around the hole

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Pocket Gopher Damage

• Pocket gophers feed on various landscape plants,
  roots and underground fleshy portions of plants
• Chewing damage to plastic irrigation pipes and
  sprinkler heads
• Tunnels can divert irrigation and cause erosion

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Controls

• Probing is used to find main tunnels
• Trapping and baiting of main tunnels
• Various trap types are used
• Traps are placed in opposing directions in main
  tunnels
• Placement also occurs at the lateral tunnels

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Tunnel Probes Probing
Tunnel Probe
Probing a Tunnel
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Pocket Gopher Traps
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Trap Placements
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Toxic Baits

• Strictly follow label directions
• Requires proper placement

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Exclusion

• Bury hardware cloth or poultry wire 2 deep and
  1 above ground
• Use 6 to 8 of 1 gravel around irrigation pipes
  and utility vaults

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Fumigation

• Rarely effective
• Requires persistence

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Moles

• Scapanus species
• Small insectivorous mammals
• Found in all but the driest areas of California
• Creates a large network of shallow
  interconnecting tunnels
• Feeds on worms, insects, etc
• Occasionally feeds on bulbs, roots and other
  plant materials

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Moles

• Stout, heavy-bodied animal
• Short, velvety dark colored fur
• Strong forelimbs with large spade-like front paws
• Short, bare pointed snouts
• Ears are not visible
• Eyes are poorly developed

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Moles
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Mole Damage

• Most damage is caused by dislodging plants
• Unsightly mounds and ridges in lawns cause
  undermining
• Mounds are circular and inline over tunnels

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Mole Mounds
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Mole Ridges
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Controls

• Trapping
• Mole traps differ from pocket gopher traps
• Scissor-jaw traps
• Harpoon traps
• Exclusion
• Toxic baits not very effective
• Eliminating food sources - insecticides

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Mole Traps
Scissor-Jaw Trap
Harpoon Trap
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California Ground Squirrels

• Spermophilus beecheyi
• Found in nearly all regions of California
• Bodies are 9 to 11 long with thick, bushy tails
• Brownish-gray color with white specks along the
  back
• Capable of climbing trees
• Usually retreat to burrows when frightened

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California Ground Squirrels
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Habitat

• Disturbed areas, roadsides, ditch-banks, fence
  rows, around buildings and edges of field crops
• Large colonies of several dozen inhabitants
• Tunnels can be 5 to 30 in length
• 2 to 4 deep
• Burrows typically have more than one opening
• Feeds within 75 yards of tunnel openings

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Burrows
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California Ground Squirrels

• Typically active through the day
• Most hibernate in winter except in mild areas
• In hottest times adults can become inactive for
  periods of 2 weeks or more
• Breed once per year
• 7 to 8 young per litter
• Breeding season in Southern California begins in
  December

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Damage

• Undermine foundations
• Cause slope failures
• Tunneling is danger to livestock, horseback
  riders
• Disease carriers particularly in areas where
  squirrel populations are high

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Bubonic Plague

• Known carriers of the fleas that carry bubonic
  plague
• Ground squirrels are susceptible to the plague
• Never handle dead ground squirrels
• If ground squirrels seem to have died for no
  apparent reason authorities should be notified

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Controls

• Various traps
• Toxic bait stations
• Fumigation
• Habitat modification
• Where allowed - shooting

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Box Trap
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Runway Traps
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Conibear Trap
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Bait Box
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PVC Bait Station
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Fumigation
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Control Schedule
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Red Fox Squirrel

• Sciurus niger
• A.K.A Eastern Fox Squirrel
• Introduced species form the eastern United States
• Established in most cities in California
• An established pest in commercial crops
• Rapid climbers escaping into trees
• Nests in trees, attic spaces, etc.

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Red Fox Squirrel

• 10 to 12 long
• Brownish orange-red fur
• Long bushy tails
• Active during the day
• Forages on ground and in trees
• Feeds on insects, fungi, pine nuts, acorns and
  other seeds, whatever handouts they receive, eggs
  and young birds

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Red Fox Squirrel
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Damage

• Damage to buildings and gardens
• Damage to fruits, nuts, various crop and
  ornamental plants
• Dig in turf areas to hide nuts
• Gnaw through phone cables
• Gnaw into irrigation pipes and sprinkler heads
• Carries diseases transmissible to humans

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Controls

• Difficult to control
• Tunnel traps
• Exclusion
• Only the red fox squirrel may be killed without
  permits other tree squirrels are protected by
  the California Fish Game Code

Natural Squirrel Control
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Meadow Voles

• Microtus species
• A.K.A. Meadow Mice
• Mouse-like 5 to 8 including the tail
• Compact, heavy-bodied with short-furred tail
• Short blackish-brown to grayish-brown long coarse
  fur
• Small eyes and partially hidden ears

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Meadow Voles
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Meadow Vole Habitat

• Often seen in aboveground runways
• Runways partially hidden under tall grass and
  other ground covers
• Active 24 hours a day, year-round
• Live in small colonies of adults and young
• Herbivorous feeding on bulbs and tubers,
  grasses, herbaceous plants, bark and roots

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Vole Runs
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Vole Runs
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Vole Damage
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Meadow Voles

• Voles breed throughout the year
• Populations can explode into the thousands per
  acre
• Female become sexually mature in 35 to 40 days
• Voles have 5 to 10 litters per year
• 3 to 6 young per litter
• Lifespan is 10 to 12 months

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Controls

• Habitat modification
• Removal or reduction of vegetative cover
• Weed-free strips around perimeters acts as
  buffers
• Cleared circles 4 dia. around trees help reduce
  damage
• Traps
• Sticky mouse traps
• Snap traps without bait
• Toxic baits
• Repellants

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Controls

• Exclusion
• Wire fences with mesh less than 1/4
• Wire mesh cylinders around trees

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Meadow Vole Exclusion
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Rabbits

• Of eight species in California 3 cause the most
  damage
• Jackrabbits Lepus californicus
• Desert cottontail Sylvilagus audubonii
• Brush rabbit S. bachmani

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Jackrabbits

• Large, fast rabbits
• Weighs from 3 lbs to 7 lbs
• 17 to 21 in length
• Grayish-brown fur
• Long, black-tipped ears
• Top of tail is black
• Long front legs
• Longer back legs

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Jackrabbits
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Jackalope
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Cottontails

• Small rabbit
• 1-1/2 lbs to 2-3/4 lbs
• 12 to 15 long
• Pale gray fur with yellowish tints

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Cottontail Rabbits
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Brush Rabbits

• Very small rabbit
• Often referred to as bunnies
• 1-1/4 lbs to 1-3/4 lbs
• 11 to 13 in length
• Brown fur

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Brush Rabbits
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Rabbits

• Most rabbits are active day or night
• Rabbits do most damage close to the ground
• Gnaw bark on young trees girdling stems
• Clip herbaceous plants and grasses close to the
  ground
• Damage irrigation pipes and sprinkler heads
• Rabbits can carry disease Tularemia (rabbit
  fever)

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Controls

• Rabbits are difficult to control
• Classified as a game mammal by the California
  Fish and Game Code
• Special restrictions apply to their control

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Exclusion

• One of the more effective means
• Use of fences at least 48 high
• They should be buried at least 10 below ground
• Mesh should be less than 1
• Gates should fit tightly
• Nothing should be around the fence for the
  rabbits to use as a perch
• Requires constant monitoring

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Other Means of Control

• Trapping
• Live traps are not recommended
• Illegal to relocate mammals without permits
• Repellants
• Various chemical repellants available
• Limited success
• Habitat management
• Shooting
• Requires licenses
• Restrictions apply

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Raccoons

• Procyon lotor
• Up to 25 lbs.
• Over 36
• Carries rabies
• Hunts fish in fish ponds
• Goes through garbage
• Can become aggressive

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Rock Dove

• A.K.A. Pigeon
• Columba livia
• To 13
• Droppings damage buildings, statues, cars, walks,
  etc.
• Nests in attics, old buildings
• Carries disease

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Opossums

• Didelphis virginiana
• The only North American native marsupial
• 24 to 36 long
• Up to 15 lbs

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Opossums

• Feeds out of pet bowls
• Also feeds on garden snails
• Eats fruits, berries and vegetables from the
  garden
• No real threat
• Other than that just plain adorable

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European Starlings

• Sturnus vulgaris
• 7-1/2 to 8-1/2
• Carries disease
• Damages fruit crops
• Competes with hole-nesting birds

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European Starlings
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House Finches

• Carpodacus mexicanus
• 5 to 5-3/4
• Damages buds and flowers
• Eats fruits and berries
• Damages seed crops and seedlings

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House Finches
Female House Finch
Male House Finch
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House Sparrow

• Passer domesticus
• 5-3/4 to 6-1/4
• Damages seedlings
• Eats fruits, buds and flowers
• Highly destructive to newly seeded lawns
• Droppings damage buildings
• Destroys nestlings of other species

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House Sparrow