The present study affirms previous research findings that volunteering satisfies personal needs but goes further by considering the factor of collective identity for volunteers and its consequences for them. The study specifically focused on older volunteers working at zoos. In the initial phase at Central Park Zoo 30 volunteers completed a short self-completion questionnaire. The second phase involved one-on-one interviews with 21 Bronx Zoo volunteers with a collective self-esteem scale. The responses indicated that the volunteers considered the collective identity of zoo volunteer to be important to their self-concept and believed that this identity is held in high public esteem. The results also suggested that identity as a zoo volunteer not only satisfies personal needs, as found by other volunteer studies, but that the collective identity supports external activism based on shared values. It was concluded that the collective environmental identity facilitated by volunteer work at the zoos provides affirmational social support for the volunteers' work as environmental conservation advocates, and enhances their sense of purpose and self-efficacy.