This depends on the amount of data you provide and how you provide it.
If you submit data through the ALA’s Record a Sighting function, it is considered to be an individual observation and a ‘fact’. Facts have no intellectual property and so do not need to be licensed, though the ALA will attribute the observation to you and license any associated images as you select.
If you provide a collection of sightings, e.g. on a spreadsheet or from a database, this is a data set and does need to be licensed. The ALA prefers to use the Creative Commons Attribution license.
See also What licence should I use?