Haliaeetus leucocephalus, bald eagle
Snyder, S. A. 1993. Haliaeetus leucocephalus, bald eagle. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-reviews/hale
| Abbreviation | Common Name | Scientific Name | Classification | Status |
|---|---|---|---|---|
| Animals | ||||
| HALE | bald eagle | Haliaeetus leucocephalus | Life Form: Animals/Bird Kingdom: Animalia Class: Bird Order: Falconiformes Family: Accipitridae Genus: Haliaeetus | Fed. Protected: Yes Nativity: Native Invasiveness: Noninvasive |
Taxonomy
The currently accepted scientific name for bald eagle is Haliaeetus leucocephalus (Linnaeus) [1]. Two subspecies, Haliaeetus leucocephalus ssp. leucocephalus and Haliaeetus leucocephalus ssp. alascanus Townsend, have been identified [16].
Synonyms
- No entry
Other Common Names
American eagle
General Distribution
The bald eagle breeds from central Alaska across Canada to Labrador and Newfoundland and south to southern mainland Alaska and the Aleutian Islands [29]. It also breeds in Baja California, central Arizona, southwestern and central New Mexico, and along the Gulf Coast from Texas to Florida [1,29]. The bald eagle occurs only locally throughout much of the Great Basin and Great Plains [1]. Bald eagles winter in most of their breeding range, from southern Alaska and Canada southward [1,29]. Resident populations are found along the Atlantic, Pacific, and Gulf coasts [16].
States and Provinces
- United States: AL AK AZ AR CA CO CT DE FL GA ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NV NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA WV WI WY DC
- Canada: AB BC MB NB NF NT NS ON PE PQ SK YK
- Mexico
Plant Communities
See Appendix.
Biological Characteristics
Bald eagle at Lower Klamath National Wildlife Refuge along the California-Oregon border.
Development and Reproduction
- Mate - late September through November in the South; January through March in the central states; late March to early April in Alaska; can vary with elevation as well as latitude; usually mate for life
- Maturity - 4 to 5 years
- Clutch - two eggs
- Incubation - 35 days
- Fledge - 10 to 12 weeks
- Longevity - up to 36 years in captivity [12,16]
Predators
No entry.
Habitat
Diet
Bald eagles eat fish, reptiles, birds, mammals, invertebrates and carrion, including that of livestock. Some food species of eagles include bullhead fish (Ictalurus spp.), alewife (Alosa pseudoharengus), chain pickerel (Esox niger), sucker (Catostomus spp.), salmon (Oncorhyncus spp.), white perch (Morone americana), smallmouth bass (Micropterus dolomieui), eel (Anguilla rostrata), sea otter (Enhydra lutris), grebe (Podilymbus podiceps), Canada goose (Branta canadensis), American coot (Fulica americana), mallard (Anas platyrhynchos), pintail (A. acuta), hare (Lepus spp.), and prairie dog (Cynomys spp.) [17,18,21,25].
Preferred Habitat
Bald eagles prefer habitat near seacoasts, rivers, large lakes, and other large areas of open water [25]. They prefer to nest, perch, and roost primarily in old-growth and mature stands of conifers or hardwoods. Eagles usually select the oldest and tallest trees that have good visibility, an open structure, and are near prey [9,11,16,18,26]. A study in Maine showed a preference for areas with "superdominant" trees. It also showed bald eagles avoided lakes surrounded by dense forest or inhabited by cold-water fishes. They used areas away from human disturbance and selected nesting sites near lakes with an abundance of warm-water fishes [21]. Another study showed a preference for nesting near lakes with a circumference greater than 7-mile (11-km). The smallest body of water supporting a nesting pair of bald eagles was 20 acres (8 ha) [25].
Eagles choose sites more than 0.75 miles (1.2 km) from low-density human disturbance and more than 1.2 miles (1.8 km) from medium- to high-density human disturbance [25]. Wintering bald eagles in New Mexico and Arizona used a disproportionate amount of snags in the largest class size (no d.b.h. given) for perching, and usually perched in the top one-third of these trees. For roosting, eagles preferred the largest live trees with open structures for visibility [13].
Cover Requirements
Habitat suitability index models have been developed for wintering bald eagles in lacustrine and estuarine habitats of the central and northern states [25]. Bald eagles need old-growth or late-successional forests for nesting and roosting [20]. Nest snags must be sturdy to support nests. Tree height or species is not as important as the abundance of comparatively large trees near feeding areas [11]. Lakes greater than 3.8 square miles (10 sq km) may be optimal for breeding bald eagles, although longer and narrower bodies of water can support breeding pairs. Nest trees should have an open form and sturdy branches in the upper one-third of the tree. Eagles nest in the overstory. Forests used for nesting should have a canopy cover of less than 60 percent (may be as low as 20 percent) and be near water. In treeless areas, bald eagles nest on cliffs or on the ground [25].
Roosting sites need not be as near to water as nesting sites. It is more important that roosting sites are in dense stands of old growth that offer protection from weather. Eagles usually arrive at roost sites after dark and depart roost sites before dawn. It is therefore is difficult to determine important roost sites through daytime observation [13].
Average home ranges for eight pairs of bald eagles in Oregon were 1,650 acres (660 ha), with an average distance between nest territories of 2 miles (3.2 km), and an average of 0.3 miles (0.5 km) of shoreline per pair [16]. In Arizona, the estimate was 24.6 square miles (64 sq km) of home range, with 9.4 to 11.2 miles (15-18 km) of shoreline for each pair.
Fire-caused Mortality
Bald eagles have continued nesting during wildfire and returned to the nest the following year [24].
Fire Effects on Habitat
Because forest structure (density and height class) determines avian community composition, changes in forest structure lead to changes in avian communities [30,31]. A stand-replacing fire will, therefore, likely change bald eagle use of a forest. Fires that destroy old-growth forest can reduce eagle populations [28]. If low-intensity, litter-reducing fires are not allowed to burn in old-growth forests, stand-replacing, high-intensity crown fires can result [6].
Fires create snags, which are important perching and nesting sites for bald eagles. Snags can possibly increase potential for lightning-caused fire when standing, and when fallen, they increase fuel loading [33]. These increased potentials may be hazardous in areas where fire control for maintaining bald eagle populations is necessary. There have been no studies to determine if the hazards of snags outweigh their benefits to eagles. Snag attrition rates have been listed for lodgepole pine forests following fire [33]. Old-growth eastern white pine (Pinus strobus) forests in Ontario continually recruit snags in the absence of fire because of their uneven-aged structure [32]. Catastrophic fires in mature and old-growth forests can create even-aged conditions which may stop continuous snag recruitment [32].
Fire Regimes
For fire regime information, search FEIS for this species by entering the species name or acronym on the home page and selecting “Fire Regime” as the publication type.
Fire Management Considerations
Fire can be used to reduce litter build-up, control disease, remove less vigorous species, and allow more vigorous trees to reach maturity, thus providing old-growth habitat for bald eagles [15].
Federal Status
The bald eagle is federally protected under the Bald Eagle Protection Act of 1962 [34].
Other Status
Information on state- and province-level protection status of animals in the United States and Canada is available at NatureServe, although recent changes in status may not be included.
Other Management Information
Humans pose the greatest threat to bald eagles through habitat destruction, pesticide use, and poaching [3,8].
In order of increasing ease, bald eagles are flushed from perches, nests, and foraging areas by human disturbance [14]. They are most easily disturbed by pedestrian traffic and least disturbed by aircraft. Establishing buffer zones of 148 to 296 feet (400-800 m) in Oregon and 167 to 592 feet (450-1,600 m) in the Southeast was recommended to reduce the impact of human disturbance on nesting pairs [14].
Silvicultural treatments for maintaining eagle habitat in ponderosa pine (Pinus ponderosa) of various age and structure, subclimax mixed conifer, Douglas-fir (Pseudotsuga menziesii) , and oak (Quercus lobata; Q. kelloggii) stands in northeastern California are detailed [4].
Table A1— Forest and range ecosystems, Bureau of Land Management (BLM) physiographic regions, Kuchler plant associations, Society for American Foresters (SAF) forest cover types, and Society for Rangeland Management (SRM) rangeland cover types in which this species occurs.
Forest and Range Ecosystems (Garrison et al. 1977)
- FRES10 White-red-jack pine
- FRES11 Spruce-fir
- FRES13 Loblolly-shortleaf pine
- FRES14 Oak-pine
- FRES15 Oak-hickory
- FRES17 Elm-ash-cottonwood
- FRES19 Aspen-birch
- FRES20 Douglas-fir
- FRES21 Ponderosa pine
- FRES22 Western white pine
- FRES23 Fir-spruce
- FRES24 Hemlock-Sitka spruce
- FRES25 Larch
- FRES26 Lodgepole pine
- FRES28 Western hardwoods
- FRES33 Southwestern shrubsteppe
- FRES34 Chaparral-mountain shrub
- FRES35 Pinyon-juniper
- FRES36 Mountain grasslands
- FRES37 Mountain meadows
BLM Physiographic Regions (Bernard and Brown 1977)
- 1 Northern Pacific Border
- 2 Cascade Mountains
- 3 Southern Pacific Border
- 4 Sierra Mountains
- 5 Columbia Plateau
- 6 Upper Basin and Range
- 7 Lower Basin and Range
- 8 Northern Rocky Mountains
- 9 Middle Rocky Mountains
- 10 Wyoming Basin
- 11 Southern Rocky Mountains
- 12 Colorado Plateau
- 13 Rocky Mountain Piedmont
- 14 Great Plains
- 15 Black Hills Uplift
- 16 Upper Missouri Basin and Broken Lands
Kuchler Plant Associations (Kuchler 1964)
- K001 Spruce - cedar - hemlock forest
- K002 Cedar - hemlock - Douglas-fir forest
- K003 Silver fir - Douglas-fir forest
- K004 Fir - hemlock forest
- K005 Mixed conifer forest
- K008 Lodgepole pine - subalpine forest
- K011 Western ponderosa forest
- K012 Douglas-fir forest
- K013 Cedar - hemlock - pine forest
- K014 Grand fir - Douglas-fir forest
- K015 Western spruce - fir forest
- K016 Eastern ponderosa forest
- K017 Black Hills pine forest
- K018 Pine - Douglas-fir forest
- K019 Arizona pine forest
- K020 Spruce - fir - Douglas-fir forest
- K021 Southwestern spruce - fir forest
- K022 Great Basin pine forest
- K023 Juniper - pinyon woodland
- K024 Juniper steppe woodland
- K029 California mixed evergreen forest
- K030 California oakwoods
- K034 Montane chaparral
- K037 Mountain-mahogany - oak scrub
- K038 Great Basin sagebrush
- K092 Everglades
- K093 Great Lakes spruce - fir forest
- K094 Conifer bog
- K095 Great Lakes pine forest
- K096 Northeastern spruce - fir forest
- K097 Southeastern spruce - fir forest
- K098 Northern floodplain forest
- K101 Elm - ash forest
- K103 Mixed mesophytic forest
- K106 Northern hardwoods
- K107 Northern hardwoods - fir forest
- K108 Northern hardwoods - spruce forest
- K113 Southern floodplain forest
SAF Cover Types (Eyre 1980)
- 1 Jack pine
- 5 Balsam fir
- 12 Black spruce
- 13 Black spruce - tamarack
- 15 Red pine
- 16 Aspen
- 18 Paper birch
- 21 Eastern white pine
- 22 White pine - hemlock
- 23 Eastern hemlock
- 30 Red spruce - yellow birch
- 32 Red spruce
- 33 Red spruce - balsam fir
- 34 Red spruce - Fraser fir
- 35 Paper birch - red spruce - balsam fir
- 38 Tamarack
- 40 Post oak - blackjack oak
- 42 Bur oak
- 62 Silver maple - American elm
- 63 Cottonwood
- 78 Virginia pine - oak
- 79 Virginia pine
- 81 Loblolly pine
- 82 Loblolly pine - hardwood
- 105 Tropical hardwoods
- 107 White spruce
- 201 White spruce
- 202 White spruce - paper birch
- 203 Balsam poplar
- 204 Black spruce
- 205 Mountain hemlock
- 206 Engelmann spruce - subalpine fir
- 207 Red fir
- 210 Interior Douglas-fir
- 211 White fir
- 212 Western larch
- 213 Grand fir
- 215 Western white pine
- 216 Blue spruce
- 217 Aspen
- 218 Lodgepole pine
- 219 Limber pine
- 220 Rocky Mountain juniper
- 222 Black cottonwood - willow
- 223 Sitka spruce
- 224 Western hemlock
- 225 Western hemlock - Sitka spruce
- 226 Coastal true fir - hemlock
- 227 Western redcedar - western hemlock
- 228 Western redcedar
- 229 Pacific Douglas-fir
- 230 Douglas-fir - western hemlock
- 234 Douglas-fir - tanoak - Pacific madrone
- 235 Cottonwood - willow
- 237 Interior ponderosa pine
- 238 Western juniper
- 239 Pinyon - juniper
- 243 Sierra Nevada mixed conifer
- 244 Pacific ponderosa pine - Douglas-fir
- 245 Pacific ponderosa pine
- 246 California black oak
- 250 Blue oak - gray pine
- 251 White spruce - aspen
- 252 Paper birch
- 253 Black spruce - white spruce
- 254 Black spruce - paper birch
- 256 California mixed subalpine
SRM Rangeland Cover Types (Shiflet 1994)
- No entry
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