Pest Activity Signs Reference

Why this matters

Pests live in places service techs visit: attics, crawl spaces, basements, behind appliances, near electrical panels, around plumbing penetrations. Spotting + flagging activity isn't just for pest control techs - every trade encounters it. Customer didn't know they had mice in the attic until you mention the droppings + the rodent damage to the wiring. This is the field card for cross-trade pest observation.

Why pests matter to non-pest trades

• Rodent gnawing on electrical wiring = fire risk
• Rodent nesting in HVAC ductwork = contamination + fire hazard
• Insect damage to wood structure = structural concern
• Termites near plumbing penetrations = water damage + structural compromise
• Rodent or pest waste in attic insulation = biohazard, contamination
• Wasps + bees near service equipment = safety hazard for techs

Flagging pest activity is part of the trusted-advisor walkthrough.

Rodents (mice + rats)

Most common signs:

• Droppings (mouse: rice-grain size, pointed ends; rat: bean-size, rounded)
• Gnaw marks on wood + plastic + cardboard + wire insulation
• Greasy rub marks along baseboards + corners (rats; oil from fur)
• Tracks in dust (look in undisturbed areas)
• Nests of shredded paper, fabric, insulation
• Smell (musky/ammonia in active areas)
• Sounds at night (scratching in walls, ceiling)
• Tunnels OR holes in insulation
• Damaged food packaging in pantries

Where they hide:

• Attic (insulation, ductwork, electrical boxes)
• Crawlspace (anywhere they can hide)
• Garage (especially storage areas)
• Behind appliances (ovens, fridges, water heaters)
• Inside utility chases + behind plumbing
• Inside walls (rare to see directly, but evidence)

What to flag:

• Active droppings (fresh = dark + moist; old = dry + crumbly)
• Chewed wires (electrical fire risk; recommend electrician + pest control)
• Heavy insulation contamination (recommend pest control + insulation remediation)
• Entry points (any hole > 1/4" can admit mice; recommend sealing)

Insects

Termites:

• Mud tubes (pencil-thick tubes on foundation walls, going up to wood)
• Discarded wings near windows + lights (swarmer event)
• Damaged wood that sounds hollow when tapped
• Frass (sawdust-like droppings)
• Pre-1980 building OR untreated wood structure = higher risk
• Refer to licensed pest control / inspector

Carpenter ants:

• Frass piles (mix of wood shavings + insect parts)
• Large ants (3/8") seen near wood structures
• Damaged wood with smooth galleries (different from termites)
• Often near moisture-damaged wood

Wood-boring beetles:

• Round exit holes in wood (1/16" to 1/4")
• Frass below holes
• Powdery wood texture from infestation
• Slow damage but cumulative

Cockroaches:

• Droppings (small dark specks, "pepper-like")
• Egg cases (oothecae)
• Smell (musty, oily)
• Sightings at night when lights come on
• Hide in warm + damp areas (around water heaters, dishwashers, under sinks)

Wasps + bees:

• Active nests (paper-like for wasps; honeycomb for bees)
• Common locations: attic eaves, soffits, exterior wall voids, around HVAC equipment
• Black hornets + yellow jackets aggressive when nest disturbed
• Safety: don't approach without protective gear; refer

Bed bugs:

• Small reddish-brown bugs (5mm)
• Dark spots on bedding (digested blood)
• Skin shedding (cast skins)
• Bites in lines on customer (typical pattern)
• Refer to pest control; specialized treatment required

Spiders: typically not a health concern (most US spiders harmless). Brown recluse + black widow exceptions; refer if customer concerned.

Mosquitoes: standing water source nearby; address drainage.

Flies: typically food + waste source; identify source.

Other animals

Bats in the attic:

• Droppings (small, dark, sparkly with insect parts)
• Smell of guano
• Sounds at dusk + dawn
• Bats are protected; many states require licensed removal during specific seasons
• Refer to wildlife control

Birds in vents / soffits:

• Nest visible from exterior
• Bird droppings on siding
• Sounds in walls / soffit
• Bird-proof venting + caps after removal

Squirrels:

• Larger gnawing damage (bigger holes than mice)
• Often visible scampering on roof
• Nests in attic (insulation + fabric)
• Entry points typically larger (1" - 2")

Raccoons:

• Large gnaw marks + paw marks
• Strong urine smell in attic / crawl
• Large nests of varied debris
• Refer to wildlife control; raccoons can be dangerous + can carry rabies

Snakes:

• Shed skin
• Tunnels at foundation OR crawl entry
• Hot weather brings them indoors
• Most snakes harmless; identify before assuming

Skunks under deck:

• Smell is unmistakable
• Often under crawl space access or deck
• Specialized removal

Where pests enter

Service techs see entry points the customer can't:

• Plumbing penetrations through exterior walls (uncaulked OR mouse-sized gap)
• HVAC line set penetrations (similar)
• Foundation cracks
• Soffit OR fascia gaps
• Roof vent flashing failures
• Attic vent screens damaged
• Bath fan / range hood vent termination missing cover OR damper
• Garage door bottom seal failed
• Gaps around pipes through firestop walls

When you make any penetration during install, seal it properly. When you see existing penetrations un-sealed, mention them.

Cross-trade observations

HVAC tech in attic: pest droppings? Insulation tunnels? Chewed cabling at the indoor coil?

Plumber under house: termite mud tubes on foundation? Rodent nests near pipes? Standing water (drainage issue + insect breeding)?

Electrician near panel: chewed wires? Nesting in panel box? (Yes, mice + insects do nest in electrical panels.)

Roofer: bird nests in soffit? Wasp nests in eaves? Squirrel entry damage?

Painter / contractor: visible insect damage during prep? Mouse droppings in cabinet bottoms?

None of these techs are pest control specialists. But the observation + recommendation to call one is value-added.

What NOT to do

• Don't try to identify rare or dangerous species: refer to professional
• Don't disturb termite tubes without inspection (some pest control inspectors want to see them undisturbed)
• Don't apply consumer pesticides on commercial scale: licensed application required in most states
• Don't kill bees: many species are protected + decline; relocate not kill where possible
• Don't handle wildlife: state laws often regulate; rabies + injury risk

Observe, recommend, refer.

Documentation

When you see pest activity:

• Photograph (date-stamped)
• Note location precisely
• Categorize: "rodent activity" / "insect damage" / "wasp nest" etc.
• Recommend appropriate specialist
• Inform customer in writing

This protects the customer (they know what's there) and you (record of observation).

Cleaning vs remediation

Light pest activity (sparse droppings, one obvious nest):

References

• NPMA (National Pest Management Association)
• State pesticide regulations + licensing
• USDA-APHIS wildlife guidance
• IICRC S520 (mold + contamination cleaning)
• Manuall internal: Crawl Space Encapsulation, Attic Moisture + Ventilation