There is no single public register of ecologists in the way there is for gas engineers, so checking a bat surveyor takes a little more than a search. What you are looking for is relevant experience, the right licence for the work, professional membership and insurance, and a report that a planning authority has accepted before.
Licences are the checkable part
Survey work that disturbs bats or their roosts requires a licence from the country's nature conservation body. An ecologist should be able to state their licence class and number, and it is a normal thing to ask before instructing.
Ask what they have done nearby
Two or three recent applications in the same authority area tell you the reports are being accepted locally. Case officers are consistent, and an ecologist who works with them regularly writes to what they expect.
Professional membership and insurance
Membership of the relevant professional body and professional indemnity insurance are both worth asking for. An ecology report is relied on by a planning authority, so a report that turns out to be wrong is a professional liability question.
What a near me listing proves
That somebody paid for a listing. Use it to build a shortlist, then ask the three questions above. Distance matters for the dusk and dawn visits, because travel at those hours is priced into the fee and a consultancy two counties away is quoting for the drive as well as the survey.
Questions people ask about bat surveyor
Does a bat surveyor need a licence?
For survey work that would disturb bats or enter a roost, yes. Non intrusive daytime inspection is different, and a competent ecologist will tell you which their proposal covers.
How do I check an ecologist?
Ask for the licence class and number, recent local applications, professional membership and insurance. Any established consultancy answers all four without hesitation.
Is the cheapest quote a problem?
It is a scope question. Confirm the number of surveyors, the number of visits assumed and whether the report and any licence application are included before comparing.