San Diego Management & Monitoring Program


Bald eagle
Haliaeetus leucocephalus

Vertebrata

Vertebrata
Kingdom Phylum Subphylum Class Order Suborder Family

Current distribution rangewide

Distribution is entirely within North America, including Canada, Alaska, and northwest Mexico [1].


Known Populations in San Diego County

Annual winter visitor to Lake Henshaw, Cuyamaca, Corte Madera, and Moreno [2].


List status

BEPA/ FP [3].


Habitat affinities

Prefers habitats with low human disturbance, but will tolerate human activity when feeding availability is high [4, 8]. Nests are generally built on cliffs, the tops of very tall conifer or deciduous trees, and close by fishable waters, i.e. lakes, rivers, reservoirs, marshes, or coastal waters. Nesting habitats are generally located in dense forested areas adjacent to large bodies of water [1]. Winters in temperate zones and dry climates in western valleys [5].


Taxonomy and genetics

Generally divided into two subspecies, H.l. alascanus, which is the larger northern species, and H.l. leucocephalus, the smaller southern species [6, 7].


Seasonal activity

Year-long, diurnal activity. Breeds from late January through August, with peak occurrences in March through July [9]. In winter eagles migrate to areas with large trees, easily accessible branches, and ice-free fishable waters away from human activity.


Life history/ reproduction

Known to build some of the largest nest, generally 5-6 feet in diameter and 2-4 feet tall [11]. Both sexes will build the nest, which can take up to 3 months to construct and will typically be used every year. They generally use tall, sturdy conifers or deciduous in southern regions that overlook the forest canopy, enabling them easy flight access and good visibility [11]. In areas lacking trees they will use ground sites or cliff faces. Nesting eagles clutch 1-3 eggs, with one brood per year. Incubation can last approximately 35 days and nest 60-100 days. Bald eagles become fully feathered at 10 weeks and will often be mistaken for golden eagles as their feathers are mostly dark brown. Once they mature and reach adult plumage, within 4-5 years they develop their iconic bald eagle characteristics. Can live 20-30 years in the wild and even longer in captivity [5].


Diet and foraging

Bald eagles eat fish, reptiles, birds, mammals, invertebrates, carrion, and may even eat garbage [12, 13].


Threats

Humans pose the greatest threat to bald eagles through habitat destruction, pesticide use, and poaching [14, 15].


Bald eagle sources