Earlybird is the name given to the early stages in Thunderbird development. Thunderbird is an open source email software with messaging, chat, and news features. It is primarily used to pull email messages from the web-based email for desktop viewing. In this way, the messages can be read even without an Internet connection. Additionally, it can act as a chat client, enabling full screen-chat with the user's email contacts. Furthermore, plugins can extend its functionality, allowing it to have features such as an integrated calendar and a task list.
Development process for Thunderbird spans three stages. These are the Beta Stage, the Earlybird Stage, and the Daily stage. After these stages are completed, only then will the product be "released" to the public for download.
During the Earlybird stage, the new features that are added in Beta stage are further "stabilized" before pushing to the final stage. This stage is participated by a number of volunteers who downloaded the early release. These participants take note of bugs and problems while using the software. After that, the notes are submitted to the Mozilla team. The Mozilla team, then collects and analyzes the notes to modify the software more. After all the modifications are done, the software is released in "daily stage" to be further tested. A new version of Thunderbird is released after the daily stage is completed.