If you want to view the specific list of subscribers who started a trial in any given month regardless of their current subscription status, then here are the steps you would take:
1. Download the Subscriptions export (Subscription Status: All, Created On, Time Range: Select the time range you need to pull data for) - https://baja.recurly.com/async_exports/new?jobsScrollPosition=0#subscriptions
2. Once downloaded, go to the "trial_started_at" column and filter the date to only show dates between Month X Day 1 - Month X Day 30/31.
Once you filter that column, you'll be able to view the list of subscribers (of all statuses) who started a trial in the month you are researching.