INTRODUCTION We present two completed research projects on Florida sub-adult Bald Eagles. The first focuses on the survival and fecundity during the first year of life. The second study follows the migratory movements of the eagles for five years post-fledging. Our goal is to share our findings with biologists and land managers to benefit future conservation and management of the species and their habitat. Please be sure to visit our publications page to download PDF copies of the findings from these studies. Also see our maps page for detailed location information.  |  |  |  | | Florida Bald Eagle nest | Nest above suburban Florida home. | Rural nest on cattle ranch | Professional tree climber retrieves nestlings. |
Abstract: We compared the reproductive biology, dispersal, and subadult survival of Bald Eagles (Haliaeetus leucocephalus) from nest sites in suburban and rural landscapes in west-central Florida, USA, from 1997 to 2001. We documented the reproductive outcome of randomly selected suburban (n = 60) and rural (n = 60) Bald Eagle nest attempts. We also used satellite tracking packages on randomly selected rural (n = 35) and suburban (n = 35) Bald Eagle fledglings. Nest-site occupancy varied among years (range = 75.0–100.0%), but averaged 90% for nests in both land-use categories. The overall mean nesting start date was similar for both groups (suburban = 11 Dec, rural =13 Dec). Bald Eagles occupying nest sites in both land-use categories raised an average of 1.3 young to 8 weeks-of age, and pairs that fledged ≥1 young raised an average of 1.7 young to 8 weeks-of-age. Most Bald Eagle fledglings from our study area migrated northward, some as far as Newfoundland, Canada. The core summering area was the Chesapeake Bay and the coastal plain of North Carolina, USA. Successful fledglings started northward migration earlier on average at rural than at suburban nest sites (124 vs. 132 days-of-age). Survival of both groups was similar until dispersal (approx 91%); however, during the first northward migration, mortality of suburban fledglings increased is proportionately. One year after fledging, survival of rural fledglings was 89% compared to 65–72% for suburban fledglings. Survival of the 2 groups was similar (84–90%) thereafter. Suburban Bald Eagles died more often from anthropogenic factors (primarily electrocution and vehicle collision) than rural Bald Eagles, though most of these deaths occurred in rural areas after dispersal from natal areas. We suggest that suburban Bald Eagle fledglings were more acclimated to dangerous anthropogenic landscape features than rural eagles, and as such did not regard them with the same degree of caution. Despite the difference in first-year mortality, population models suggest that both groups are experiencing positive population growth rates. Text from: Millsap. B., T. Breen, E. McConnell, T. Steffer, L. Phillips, N. Douglass, and S. Taylor. 2004. Comparative fecundity and survival of Bald Eagles fledged from suburban and rural natal areas. Journal of Wildlife Management 68:1018-1031.
 |  |  | | Nestling eagles | Satellite transmitter package with Teflon backpack harness. | Fitting satellite transmitter harness in place. Eagles are hooded to keep them calm. |
Abstract: Long distance migration movements of Bald Eagles (Haliaeetus leucocephalus) prevent a thorough study of their migration movements with traditional methods of banding and VHF radio-telemetry. We used satellite telemetry to determine important use areas (IUAs) for 48 migratory Florida sub-adult Bald Eagles. We used a nearest neighbor analysis to identify daytime foraging and nocturnal roosting IUAs. We found 151 daytime IUAs (mean = 610 km2 95% kernel density, 95% CI: 515 – 706) in 20 states and provinces, and 50 nocturnal roosts in 8 states and provinces. Most roosts (68%) were visited by multiple eagles. We recommend locations of IUAs be added to GIS databases for future management and conservation land purchases. Bald Eagle nesting habitat receives federal protection, but habitat used by non-breeding sub-adult eagles is mostly unprotected. We recommend conserving and protecting sub-adult nocturnal roosts and managing undeveloped shoreline forest for eagles within the IUAs identified in this study. Text from: Mojica, E.K. 2006. Migration, home range, and important use areas of Florida sub-adult Bald Eagles. M.S. Thesis. The University of Georgia, Athens, GA.  | | Transmitters sit on the middle of the back and allow full range of wing movements. |
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