Target specific subscribers in your list and save them in a segment, for example, send out birthday emails.
To create your own segments within your MailChimp lists you will need to have a list created. Create a list here.
First go to your Lists and select Manage Subscribers > Segments
Select Create Segment and then you will have the options to add as many conditions you like.
Click on image above to enlarge for higher quality.
Once you set the segments up to how you like you can Preview Segments and select Save Segments.
Then you can give your saved segment a name for ease to find later on.
Once you have given it a name and clicked Save, you will be able to find it when you set up your campaigns under Recipients > (Your List) > Send to saved segment.