4.5 Bats, Wildlife & the Limits of a Pesticide Licence

4.5 Bats, Wildlife & the Limits of a Pesticide Licence

[!IMPORTANT] A licence to apply pesticides is not a licence to remove animals. There is no registered pesticide in Canada for bats, raccoons, squirrels, skunks or opossums. Using a rodenticide on any of them is an off-label use and therefore an offence under s. 3 of the Pesticides Act, quite apart from the wildlife legislation it breaches. This section exists so you recognise the boundary the moment you meet it.

---

Bats in Ontario Buildings

Ontario's building-dwelling bats are insectivores that consume large numbers of night-flying insects. Two species account for most structural complaints: the big brown bat (Eptesicus fuscus), which commonly overwinters in buildings, and the little brown myotis (Myotis lucifugus), a colonial species that historically formed large maternity roosts in attics and barns.

Why this matters legally. White-nose syndrome collapsed Ontario's cave-hibernating bat populations, and several species — including the little brown myotis, the northern myotis and the tri-colored bat — are listed as endangered under Ontario's Endangered Species Act, 2007. Killing, harming or harassing a listed species, or damaging its habitat, is prohibited. Because the species cannot reliably be told apart by a homeowner or by a technician glancing into a dark attic, the operational rule is simple: bats are never killed, only excluded.

Where they roost. Attics and gable ends, soffit and fascia gaps, ridge vents, chimney chases, behind shutters and siding, in barn lofts and church steeples. Entry points are small — a bat exploits a gap of little more than a centimetre.

Signs. Guano accumulations beneath entry points (dark, crumbly, glittering with insect wing scales, and unlike mouse droppings it crushes to powder), staining and rub marks at entries, chittering audible at dusk in warm weather, and a distinctive musty odour in a heavily used roost.

---

Exclusion: The Only Lawful Control

Bat exclusion is a construction task performed in a strict order.

1. Inspect at dusk. Watch the structure at emergence to find the entry points actually in use. Interior inspection alone will miss most of them.
2. Seal every secondary opening except the active entries, using durable materials.
3. Fit one-way devices — netting, tubes or valves — over the active entries so bats can leave but cannot return.
4. Leave the devices in place long enough for the entire colony to exit, typically several days to a week of suitable weather.
5. Remove the devices and permanently seal the last openings.
6. Clean and remediate the guano deposit with the same respiratory precautions used for bird droppings, since guano also supports Histoplasma capsulatum.
7. Treat for bat bugs (Cimex adjunctus) if present. They closely resemble bed bugs, and once the host colony is gone they disperse into living space — a very common source of a "bed bugs but no bed bugs" complaint.
8. Offer a bat house as a mitigation where the client is receptive; it does not make the exclusion lawful by itself, but it is good practice for a species at risk.

[!WARNING] The maternity timing rule. Female bats form maternity colonies in late spring, and the pups cannot fly for several weeks. Excluding during this period seals flightless young inside to die — a welfare disaster, an offence in the case of a listed species, and a guaranteed odour and dermestid problem for your client. As a working rule, do not exclude between roughly the beginning of June and the end of August, until the young are flying. The lawful windows are spring before the colony forms and late summer to autumn once the young are volant. Confirm current timing guidance with the ministry before scheduling.

---

Rabies and Human Contact

Bats are the principal rabies reservoir encountered in Ontario buildings. Bat bites can be small enough to escape notice, which is why exposure is defined broadly.

• Never handle a bat with bare hands. Use heavy gloves, a container and a piece of stiff card.
• Any direct contact — a bite, a scratch, or handling without gloves — requires immediate washing of the site and contact with the local public health unit.
• A bat found in a room with a sleeping person, an unattended child, or a person unable to report contact is treated as a possible exposure even if no bite is seen, and must be reported.
• Where an exposure is suspected, the bat should be contained rather than destroyed by crushing the head, so that testing remains possible. Public health will direct what happens next.
• Post-exposure decisions belong to public health and medical practitioners, never to the pest control operator.

---

Raccoons, Squirrels, Skunks and Opossums

These are wildlife, not pests within the meaning of your pesticide licence.

Where you add value: identification, inspection, documenting the entry points, exclusion and screening once the animal is out, cleaning and ectoparasite treatment of the vacated harbourage, and a clear referral to a licensed wildlife control operator. That is a complete, honest service — and it protects both the client and your licence.

Field scenario: the attic call in July

A homeowner in Peterborough reports scratching in the attic and finds "mouse droppings" on the porch below the gable. The droppings crumble to powder and glitter with insect wing fragments.

Reading it correctly. Glittering, crumbly droppings under a high entry point are bat guano, not mouse faeces. It is July, so a maternity colony with flightless pups is likely. Do not exclude now. Confirm the entry points with a dusk emergence watch, seal secondary openings, and schedule the one-way devices for late summer once the young are flying. Advise the client not to attempt anything themselves, explain the rabies rule for any bat found in a bedroom, and quote the guano remediation and bat bug treatment as part of the same project. Reaching for a rodenticide because the droppings were called "mouse droppings" would be an off-label use against a species that may be listed as endangered — the worst outcome available on this job.