Habitat Use, Movements, Migration Patterns, and Survival Rates of Subadult Bald Eagles in Northern Florida
Notice bibliographique
Résumé
The state of Florida supports over half of the breeding population of Bald Eagles (Haliaeetus leucocephalus leucocephalus) in the southeastern United States; this represents a significant resource for the Southeast and for Florida.Currently, primary management emphasis and protection is focused on bald eagle nest sites.No habitat protection or management activities are aimed at foraging, roosting or loafing areas for subadult eagles.In fact, habitats and habitat characteristics important to sub adults have not been quantified.In this study, I examined various aspects of eagle biology that might be pertinent to survival or management of the Florida subadult eagle population.Specifically, using radiotelemetry, I examined post-fledging habitat needs, factors affecting timing of migration, local movements, habitat use, and survival in north-central Florida from spring 1987 through spring 1991.Fledgling eagles (birds prior to their initial migration) remained dependent on adults and remained within 4 km of the natal nest until they initiated migration (approximately 7 wk post-fiedging).It was determined that habitat protection within the 229 m primary protection zone used in Florida was not sufficient to meet the habitat needs of fledgling eagles and that the protection period should extend until fledglings initiate migration in the summer.Timing of migration for fledgling and 1-to 4-year-old eagles appeared to be correlated more with prey availability than with temperature, although both factors appear to affect migration.Locations of radio-tagged eagles outside of Florida ranged from South Carolina to Prince Edward Island, Canada.Data suggest that eagles are philopatric to summering areas, which emphasizes the need for protection of significant summering areas.Known and assumed mortality occurred primarily during migration in northern states.The 1 V2 year age class had the lowest survival.Survival was significantly lower for eagles fledged from 1-chick nests and for the younger chick in 2-chick nests.The minimum survival rate through 4« years of age was 50% and did not vary by sex.After subadults returned to the north-central Florida study area in the fall, individuals continued to use the same general areas each year.Temporally and locally abundant food sources resulted in temporary small concentrations of eagles.Certain portions of the study area were used consistently each year by large numbers of eagles.Subadult eagles were not distributed randomly over the study area.Logistic regression analyses revealed that eagles tended to be located close to large water bodies, and eagle nests were frequently in cypress and marsh habitats, and avoided main roads and developed areas.Immature eagles (1-year olds) tended to be located closer to eagle nests than 2-to 4-year-olds Thus, management for subadult populations must include these heavily used concentration areas that supply the habxtat features preferred by subadults.Survival of subadults may be affected if a highly used area becomes unsuitable.-
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».