In birdwatching, a "tickable species" refers to a bird that can be added to a birder's life list, a birding challenge or other birdwatching records. Essentially, when a birder sees a new tickable species for the first time, they can "tick" it off on their life list. This concept is an integral part of the birdwatching hobby for many enthusiasts.

Ornithological groups worldwide are generally responsible for creating checklists of tickable species based on historical records of of an particular species in a specific listing area. For example, in the USA, the American Birding Association (ABA) maintain the ABA Checklist, a list of tickable species in the ABA Area. This ABA Area is essentially North America north of Mexico plus the Hawaiian Islands. In the UK, the British Ornithologists’ Union (BOU) maintain the British List, a list of tickable species in Britian.

Birda uses these official lists to tag all sightings as either Tickable or Non-tickable. If an official checklist of tickable species does not exist for any particular country, then Birda will create its best-estimate list for the location.

While users can post sightings of non-tickable species on Birda, it's important to note that these may not count towards some Birda challenges (this will be made clear in the challenge description).

Understanding and adhering to the concept of tickable species helps maintain the integrity and challenge of birdwatching. It encourages enthusiasts to seek out species that are part of the natural ecosystem, enhancing the experience and contributing to citizen science data.

Logging non-tickable species is also really important because data collected on non-tickable helps conservation researchers better understand the expansion of non-native species.