Kleptoparasitism, the stealing of food from individuals of either the same or a different species, is a common behavior among seabirds. Little is known about the age-related differences in kleptoparasitism behaviors, which may elucidate how this behavior emerged and is maintained in populations. We observed the kleptoparasitic behavior of Fregata magnificens (Magnificent Frigatebirds) on the Dry Tortugas, a group of islands west of Key West, FL. For each kleptoparasitic event, we recorded whether an adult or a sub-adult frigatebird made the attack; whether the potential host was approached while it was in the air, in the water, or on the ground; the duration of the chase; and whether an individual or group of hosts was approached. Adult females most often approached potential hosts in the air (92% of recorded encounters), while sub-adults approached more potential hosts on the ground (61% of recorded encounters). Water approaches were rarely performed by sub-adults and never by adults. Adult females tended to spend significantly more time on each chase than did sub-adults, and adult females sought out individual hosts (69% of recorded encounters), while sub-adults seemed to prefer groups of hosts (78% of recorded encounters). These age-related differences in feeding behaviors may represent a period of learning in young birds that will make them more effective kleptoparasites as adults. In general, these age-related differences in behavior may lead to a better understanding of the pressures that have led to the development and maintenance of kleptoparasitic feeding strategies in frigatebirds.