eBird is a database of citizen science bird observations that allows for tracking of bird species distribution and abundance worldwide. The online database is freely accessible and made possible by millions of bird observers across the world uploading information from field observations. The only required input is location in order to access records of bird sightings on a specified site. For each site that appears in eBird, dates, locations, and number of birds of a particular species are uploaded by observers. This information may be accessed and used to assess bird populations and abundance for a particular site, provided that information for that site is available. Records entered by observers go through a rigorous eBird verification process to ensure an adequate level of data quality. Other features of the eBird site may be used to understand which bird species should be present or are likely to be present in a particular region.