Population trends and breeding ecology of the Florida burrowing owl (Athene cunicularia floridana) on the Florida Atlantic University campus, 1990--2003

From 1990 to 2003 a study of the declining population of Burrowing Owls (Athene cunicularia floridana) on the Florida Atlantic University campus in Palm Beach County indicated that the location of unsuccessful owl (those not producing chicks) territories was the cause of their decline. Over the 14 years, the number of successful adult owls and the number of chicks remained fairly constant because they were located in areas where campus expansion remained minimal. Also, 76% of owls that reused territories were reproductively successful, whereas only 43% of owls on newly-established territories were successful. Additionally, territories occupied for seven years or more averaged 1.27 chicks per territory per year, while territories occupied less than seven years averaged 0.17 chicks. Furthermore, all of the territories occupied for seven years or more produced chicks, but only 58% of territories occupied less than seven years did so. Territories located in Pomello sand produced more chicks, as burrows there never flooded and also were less exposed to construction. Chicks from territories with one burrow dispersed faster (75 days of age) than did those from territories with two or more burrows (119 days of age).