This is very annoying and can be such a time waster for you. As the “in house” recruiter, whether you be the HR Manager or someone designated to doing recruiting, it can take up so much of your time when unsolicited recruiters call you.
First of all, find out if your company/organization has a policy around working with recruiters. Is there a preferred vendor list? If so, find out who is on it and stick with it until you can help change it. There is no point in wasting your time with a recruiter who can’t be paid by your company because they are not on the list. If you are happy with the service you are getting from the existing recruiters, there is no point making a change any time soon. However, if you believe there is room for improvement, carve out some time in your week to actually take a call or two from those recruiters and ask them to walk you through their recruitment process. If they are simply calling to “flog a resume”, they are not genuinely interested in working with you and developing a plan. They should be able to properly articulate all the steps they go through to help you find the ideal candidate. Listen to them and see if this is the type of person you can work with. After all, you are trusting them with a large portion of your responsibilities so you want to be sure they are trustworthy! Find out if they have the network and the “reach” capabilities to actually identify and recruit those “hard to find candidates” who don’t apply to postings!
You can make a change to another recruiter but don’t do it unless it makes sense for you and your organization. Do your homework first and don’t switch just because someone presented you a great resume – see if they are in it for the long term with you!
Don’t be afraid to say “thanks for calling but we won’t be entertaining another recruitment firm in the near future”. Sometimes, it is better to be direct and if the recruiter is listening, they will politely ask if they can continue to keep in touch with you in case your situation changes. It only make sense – you don’t have time to waste.