The original entry in the ongoing Monster Manual Encounters series, the Aarakocra marks the first "monster" in 5E's Monster Manual. This encounter features a group of aarakocra in need of the party's assistance to drive off an elemental threat, rather than an encounter featuring the aarakocra as the party's opposition. The encounter is designed for characters between 5th & 8th level, though there is plenty of room to adjust for lower- or higher-level groups.
Each entry in the Monster Manual Encounters series is a setting-neutral (but Forgotten Realms friendly) encounter designed to be dropped into any ongoing campaign with a minimum of fuss. The encounters are self-contained "micro-adventures" intended to show off the featured monster in a unique way, rather than being just another random encounter. Many adventures leave a few dangling leads the party could choose to follow if they wished, to give the DM an easy starting point for a longer adventure.