Bald Eagles

Category: Others/ Misc

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Bald Eagles—“Masters of the Sky” : 

Bald Eagles—“Masters of the Sky”

Raptors—“Birds of Prey” : 

Raptors—“Birds of Prey” A raptor is a carnivorous bird. All raptors share at three characteristics: Keen eyesight Eight sharp talons A hooked beak Raptors include eagles, hawks, owls, & vultures.

All About Eagles . . . : 

All About Eagles . . . There are 59 species of eagles worldwide 4 major groups America’s Eagles: Bald Eagle Golden Eagle The Bald Eagle is only found in N. America

Bald Eagles—The National Emblem : 

Bald Eagles—The National Emblem Bald eagles were declared the U.S. national emblem in 1782 The bald eagle symbolizes: Freedom Spirit Pursuit of excellence

Bald Eagles(Haliaeetus leucocephalus) : 

Bald Eagles(Haliaeetus leucocephalus) The name "bald" is a misnomer (name doesn’t suit what its used for). The Bald Eagle received its name from the Old English word balde that meant white. The scientific name means "white-headed sea eagle”.

Bald Eagle Characteristics : 

Bald Eagle Characteristics White head & tail feathers Dark brown body Yellow beak, feet, & eyes Size: 29-42 inches long 7-15 pounds Wing span = 6-8 feet 7000 feathers cover their body from head to tail! Life span = 15-30 years

Can you tell which of these eagles is a female? : 

Can you tell which of these eagles is a female? Eagles are NOT sexually dimorphic—cannot distinguish between sexes based on appearance! Females are slightly larger than males: Wings Feet Beak

Bald Eagle Call : 

Bald Eagle Call Bald eagles like other birds use calls to communicate: A way of reinforcing the bond between the male & female To warn other eagles and predators that an area is defended. Shrill, high pitched, and twittering

Bald Eagle Adaptations : 

Bald Eagle Adaptations

Bald Eagle Beak : 

Bald Eagle Beak The hooked bill of the bald eagle is used for tearing prey apart. The upper & lower portion overlap and act like sharp scissors that slice through tough skin! The bald eagle also uses its beak as a weapon, a grooming tool and to feed the young. The beak of the eagle grows continuously during their lifetime.

Bald Eagle Beak : 

Bald Eagle Beak

Bald Eagle Eyes : 

Bald Eagle Eyes Bald eagles have excellent eyesight & color vision. With two centers of focus, eagles can see both forward and to its sides at the same time! Bald eagles can spot a fish when they are hundreds of feet above water!!! They can also spot prey at great distances when they are perched (up to 1 mile)!!

Bald Eagle Eyes : 

Bald Eagle Eyes

Bald Eagle Feet : 

Bald Eagle Feet Eagles have special feet called “talons”. Talon Characteristics: Four large toes Grooved underneath Have needle-like pads Talons used to penetrate the flesh of prey. Eagle talons are EXTREMELY powerful—1000 lbs pressure/in2 The talons, like their beak, grow constantly.

Bald Eagle Feet : 

Bald Eagle Feet

Bald Eagle Wings : 

Bald Eagle Wings The large wingspan of bald eagles allow them to do very little wing flapping! An eagles wings are long and broad, making them effective for soaring. Eagles use "thermals," rising warm air currents to help them cover great distances while soaring.

Bald Eagle Wings : 

Bald Eagle Wings

Bald Eagle Tail : 

Bald Eagle Tail As the eagle flies, it spreads its tail feathers, in order to steer and maneuver itself in the air. The eagle's tail is also used to help with quick landings and stability when walking or swooping toward prey.

Bald Eagle Tail : 

Bald Eagle Tail

Bald Eagle Flight : 

Bald Eagle Flight Bald Eagles can fly at speeds up to 65 mph in flight and up to 150 or 200 mph in a dive! Bald eagles can fly to altitudes of 10,000 feet or more. Bald eagles can soar aloft for hours!

Habitat : 

Habitat Bald Eagles live near open water such as lakes, marshes, seacoasts and rivers, where there are plenty of fish to eat and tall trees for nesting and roosting. Bald eagles live in large, deep nests in tall trees that are close to water.

Distribution & Migration : 

Distribution & Migration Bald Eagles have a presence in every U.S. state except Hawaii. Some bald eagles migrate south in the winter as lakes and streams freeze over. NOT all eagles migrate—if there is open water eagles may winter in the North. Migrating eagles fly in large groups (kettle).

Feeding : 

Feeding Diurnal (day time) hunters The bald eagle survives mostly on a diet of fish, but they will eat rodents, ducks, muskrats, etc. Bald eagles rely heavily on carrion (dead animals)—especially dead fish! Road killed deer are a favorite food in the Midwest! Bald eagles steal food from each other as well as other raptors. Only 1 out of 18 attempts is successful!!

More on Feeding . . . : 

More on Feeding . . . An eagle protects its food by tenting (partially opening its wings). The eagle holds its prey with one talon, holds onto its perch with the other, then tears off each bite with its beak. An eagle can consume 1 lb. of fish in about 4 minutes—WOW!! Bald eagles do no have to eat every day.

Mating & Courtship : 

Mating & Courtship Bald eagles become sexually mature at 5-6 years old. Bald eagles are monogamous and stay together for life unless one of them dies. The mating season varies by region. Bald eagles perform a courtship, which includes diving and locking talons in the air.

Nesting : 

Nesting They build large nests (aerie) at the top of tall trees. Nests are lined with twigs, soft mosses, grasses and feathers. A typical nest is 2-feet deep, 5-feet in diameter, and weighs several tons! The bald eagle returns to the same nest year after year, sometimes adding on to the nest so much, it exceeds 10-feet in diameter.

Egg Laying : 

Egg Laying The female eagle lays 1-3 eggs. Eggs are a speckled, off white color & about 3”x 2” in size. Both males and females incubate the eggs. Eggs hatch after a 35 day incubation period. The eggs hatch in the order they were laid & are laid several days apart, so the 1st eaglet has a size advantage in case food is scarce.

Bald Eaglets : 

Bald Eaglets Baby eagles are referred to as “eaglets” Eaglets weigh ¼ pound at hatching and within three months gain up to 12 pounds! The feathers of a newly hatched eaglets are light gray. The feathers turn dark brown around 12 weeks when they leave the nest.

Parental Care : 

Parental Care Nest watch & eaglet feeding duties are shared by both parents. Eagle parents spend a lot of time feeding eaglets as they add 1 lb of body weight every 4-5 days. Eaglets are able fledge (leave the nest) when they are 3 months. Only about 40% eaglets survive their 1st flight!

Immature Bald Eagles : 

Immature Bald Eagles Adult bald eagles do not get their distinctive appearance until they are 4-5 years old Young eagles (<3 years of age) are mainly brown with specks of white When eagles reach 3 years of age they have white feathers with brown mottling

Predators : 

Predators Because of their size, adult bald eagles have very few predators. Some animals that eat the eggs or nestlings include squirrels, raccoons, ravens, and great-horned owls.

Crows—“A Thorn in an Bald Eagle’s Side” : 

Crows—“A Thorn in an Bald Eagle’s Side” Crows (who don't like any raptors) will “harass” bald eagles.

Competitors : 

Competitors Eagles compete with each other for food, nest sites, mates, etc. Great Horned Owls sometimes compete for eagle nests. Great Horned Owls and mice also nest in the lower parts of a big nest made by eagles -- even when the eagles are using it! Some birds like osprey, gulls, ravens, & hawks compete with eagles for food.

Mortality : 

Mortality Major causes of death of bald eagles include: Starvation Drowning Hypothermia Gun shot wounds Lead poisoning Poisoning Electrocution Car collisions

Slide 38: 

Causes of mortality of bald and golden eagles over the past 30 years.

Bald Eagle History : 

Bald Eagle History Bald Eagles were once very common throughout most of the US--estimated at 100,000-300,000 birds in the early 1700s. By 1963 only about 800 bald eagles in the lower 48 states. Today, there are an estimated 50,000 bald eagles in the US, with 80% of them found in Alaska.

DDT : 

DDT Miracle pesticide Gained widespread use after WWII DDT was used to control insects in agriculture and insects that carry diseases such as malaria.

DDT & The Food Chain : 

DDT & The Food Chain DDT washed into lakes and streams. DDT was absorbed by aquatic plants and small animals that were eaten by fish or waterfowl. The contaminated fish & waterfowl were consumed by larger organisms, like bald eagles.

DDT’s Impact on Eagles : 

DDT’s Impact on Eagles DDT interfered with the bald eagle's ability to develop strong shells for its eggs. Bald eagles began laying eggs with shells so thin they often broke during incubation or otherwise failed to hatch. This caused their populations to plummet (decrease).

Rachel Carson : 

Rachel Carson Biologist (USFWS) & nature author Told the public about the dangers of DDT in a note in Readers’ Digest & later her famous book Silent Spring "The more clearly we can focus our attention on the wonders and realities of the universe about us, the less taste we shall have for destruction." -- Rachel Carson (1954)

Silent Spring : 

Silent Spring This book provides a detailed description of how DDT enters the food chain and accumulates in the fatty tissues of animals. The book's most haunting and famous chapter, "A Fable for Tomorrow," depicted a nameless American town where all life -- from fish to birds to apple blossoms to human children -- had been "silenced" by the insidious effects of DDT. This controversial book led to the ban of DDT in the U.S. in 1972 (other countries still use it today!).

Historical Conservation Efforts : 

Historical Conservation Efforts Bald Eagle Protection Act (1940)—prohibited killing or selling of bald eagles. Endangered Species Preservation Act (1966) Banning of DDT by the Environmental Protection Agency (1972) Endangered Species Act (1973)—first listed as endangered in 1973

Current Conservation : 

Current Conservation Currently listed as threatened on the Endangered Species Act (ESA) Threatened = “any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.” Proposed delisting in 1999, but still listed

Migratory Bird Treaty Act (1918) : 

Migratory Bird Treaty Act (1918) This act protects all migratory birds, including bald eagles, in the U.S. It prohibits taking, killing, possessing, transporting, and importing migratory birds, their eggs, parts, & nests.

The Bald & Golden Eagle Protection Act : 

The Bald & Golden Eagle Protection Act The successor to the Bald Eagle Protection Act. Prohibits, except under certain specified conditions, the taking, possession, transportation, export or import, barter, or offer to sell, purchase or barter a bald or golden eagle, alive or dead, or any part, nest, or eagle egg

Recovery : 

Recovery Great conservation efforts have made the bald eagle a model of effective recovery efforts. There are currently over 5,000 nesting pairs and 20,000 total birds in the lower 48 states. There are over 35,000 Bald Eagles in Alaska.

Continued Threats to Bald Eagles : 

Continued Threats to Bald Eagles Habitat loss Human disturbance Collisions with vehicles while eagles feed on road killed animals (40% of eagle deaths) Pesticides, lead, and other poisons in the environment.

Eagles & Lead Poisoning : 

Eagles & Lead Poisoning Eagles become poisoned by lead after consuming food sources (fish, loons, etc) containing the lead.

Slide 54: 

Nationwide distribution of lead-poisoned eagles.

Poisoning from Lead Shot : 

Poisoning from Lead Shot One major source of lead is from lead shot used by duck hunters. Waterfowl and other birds ingest lead shot when searching for food. Lead poisoning kills an estimated 1.5 to 3 million waterfowl/year. Lead shot was banned for waterfowl hunting in 1991.

Poisoning from Lead Fishing Tackle : 

Poisoning from Lead Fishing Tackle Another major source of lead poisoning is lead tackle, mainly sinkers (small weights used to sink the hook & bait), used by anglers. Many sinkers are lost into the water—lines get snagged & are cut. Waterfowl eat the sinkers that they mistake as grit & food (see picture). Just eating 1 lead sinker can kill a loon!!

“Let’s Get the Lead Out!!” : 

“Let’s Get the Lead Out!!” Anglers can help prevent lead poisoning by using inexpensive and ecologically sound alternatives to lead tackle. Anglers can use sinkers and jigs made from non-poisonous materials such as tin, bismuth, steel, and tungsten-nickel alloy.

What You Can Do To Help . . . : 

What You Can Do To Help . . . EDUCATE YOURSELF & OTHERS!!!! Support habitat restoration programs! Buy non-lead fishing tackle! Adopt an Eagle Nest Program (WI DNR) Buy WI Endangered Resources License Plates

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