Bird vocalization includes both bird calls and bird songs.
Birdwatching, or birding, is a form of wildlife observation in which the observation of birds is a recreational activity or citizen science.
Citizen science (CS; also known as community science, crowd science, crowd-sourced science, civic science, volunteer monitoring, or networked science) is scientific research conducted, in whole or in part, by amateur (or nonprofessional) scientists.
Creative Commons (CC) is an American non-profit organization devoted to expanding the range of creative works available for others to build upon legally and to share.
The Netherlands (Nederland), often referred to as Holland, is a country located mostly in Western Europe with a population of seventeen million.
Open content is a neologism coined by David Wiley in 1998 which describes a creative work that others can copy or modify freely, without asking for permission.