LONG-TERM CHANGES, 1958-2010, IN THE REPRODUCTION OF BALD EAGLES OF FLORIDA BAY, SOUTHERN COASTAL EVERGLADES

The population of Bald Eagles (Haliaeetus leucocephalus) breeding in Florida Bay, located within Everglades National Park, has been the subject of one of the longest running monitoring programs for any large raptor species worldwide, with reproductive data collected for 49 breeding seasons since 1958. The overall reproductive trends in this nesting population indicated that the population has transitioned from one at or near carrying capacity to one in decline, with territory occupancy decreasing as much as 43%. This contrasted with observed trends for the state of Florida, where populations increased >300% over the past 25 yr. The rate of nesting attempts in Florida Bay remained high (0.83 +/- 0.11 [SD]; number of active territories/number of occupied territories) over the period. Mean annualized brood size was 7.48 +/- 0.16 young/successful territory and mean productivity was 0.81 +/- 0.21 young/occupied territory, which are comparable to those of other Bald Eagle populations. There were significant increases in ratios of active territories/occupied territories, successful territories/occupied territories, and young/occupied territory, despite decreased occupancy. Increases in these rates have allowed overall production of the Florida Bay population to remain stable; however, given the current decreasing trend in territory occupancy, this population should be considered at risk. Changes in Bald Eagle reproductive parameters corresponded with significant ecological changes documented in Florida Bay and southern coastal Everglades and may serve as possible long-term indicators for the health and recovery of the southern Everglades as restoration efforts progress.