Frequently Asked Questions

This will be an ever-evolving page as those really inspired questions are heard at school or public programs, are asked in relation to a nest camera feed, or in some way come across our "desk." The folks involved with this project have accumulated several decades of experience in natural resources programming and if they don’t know the answer 'off the top,' then one of the reputable sources of info found on the Learn More page will be used!

If these questions spark more questions... check out the links on the
Learn More page and research the answers!

Click on an FAQ category and browse the questions. Don't see your question, then send us an email.


Terminology

  • I've heard words like nocturnal and diurnal. What do they mean?
    • The term "nocturnal" means a night time hunter and "diurnal" means a daytime hunter. Have you heard the term "crepuscular?" Crepuscular animals are active dawn and dusk hunters.
  • What is the difference between 'raptor' and 'bird or prey?'
    • The word raptor comes from the Latin rapere and means "to seize." A bird of prey is a bird that eats another animal. The terms may mean different things, but both terms describe the same group of birds. These birds have talons to seize or take their prey.
  • What is a pellet?
    • A pellet is accumulated undigested material, in the case of eagles and hawks they are primarily hair. An owl pellet contains bones of the animals they have eaten; this is because an owl has less stomach "juices" to digest the bone.

Bald Eagle Biology and Natural History

  • Did you know? (Factoids from USFWS Midwest Region)
    • The bald eagle is truly an all-American bird; it is the only eagle unique to North America.
    • Nests are sometimes used year after year and can weigh as much as 4,000 pounds.
    • Bald eagles may live 30 years in the wild (even longer in captivity).
    • Bald eagles pair for life, but if one dies, the survivor will accept a new mate.
    • In hot climates, like Louisiana and Florida, bald eagles nest during winter.
    • Bald eagles get their distinctive white head and tail only after they reach maturity at 4 to 5 years of age.
  • Where can I see bald eagles in the United States?
    • Bald eagles live in Canada, Alaska, and the lower-48 states. Bald eagles are the easiest to see in the winter when northern eagle populations are migrating south from their breeding territory and combined with local populations will all hang out together in good feeding areas like open rivers and the open water below a lock and dam or a water impoundment (like below Lake Red Rock and Saylorville Lake in Iowa).
  • When do bald eagles get white head and tail feathers?
    • Hatch-year birds have almost all dark feathers. Juveniles (2nd year to adulthood) have mottled brown feathers with some white. The birds gradually get their adult plumage by age 4-5. The adult plumage is a blackish-brown body with the white head and tail feathers. As the birds age, the beak begins to turn yellow.
  • When is an eagle old enough to breed?
    • Eagles are sexually mature at age 4 or 5, but some birds do not start breeding until older.
  • How can you tell the male and female apart in the nesting pair?
    • Unless the pair is side-by-side, most of us can't tell them apart, they look the same. Remember that female eagles, like all female raptors, are larger than the males. Males generally weigh around 8 pounds and females in the 10-12 pound range. The female has a bigger beak (more depth to the bill) and bigger feet, particularly a bigger hallux talon or back toe. The difference by gender is called sexual dimorphism.
  • How many feathers does a bald eagle have?
    • Bald Eagles have approximately 7,000 feathers. Feathers, like hair and nails, are made of keratin. Feathers are made of interlocking, microscopic barbules that are light, but very strong. Layers of feathers trap air to insulate birds against cold and protect them from rain.
    • Check out this blog post from Amy at Raptor Resource Project about feathers written after she watched "mom Decorah" incubate two eggs in the nest as she was covered with snow.
  • Why do young eagles look bigger than their mom and dad?
    • Young eagles' wings and tail are a little bit longer than their parents. These longer feathers are like ‘training’ feathers to help them learn to fly and to maneuver. Most young birds also have an extra fat reserve to help them when learning to hunt for themselves.
  • How fast do eagles grow?
    • If food and conditions are good, young eagles can gain a pound a week. 10 weeks = 10 pounds.
  • How are eagle populations monitored in Iowa?
    • The Iowa Department of Natural Resources has a volunteer program that allows people to become involved in monitoring Iowa nesting eagles. For more information visit the volunteer wildlife monitoring page of the IDNR.
  • Where can I find out information about the decline and recovery of bald eagle populations?
  • Why do eagle numbers seem to go up in the winter? Does this number change every year?
    • Beginning in November, hundreds of bald eagles migrate to Iowa to winter along our river corridors, below dams at the many reservoirs (like Lake Red Rock and Saylorville), and below the locks on the Mississippi River. Migrating eagles are not going to stay in Iowa, but will return to their nesting territories in late February or early March. In the first few weeks of January, Iowa DNR conservation officers, biologists, and other professionals participate in the US Fish and Wildlife service sponsored Mid-Winter Waterfowl Survey that includes counting the numbers of juvenile and adult eagle’s seen in their monitoring area. This information is tallied to include each county’s total number of waterfowl and eagles and sent into the U.S. Fish and Wildlife Service where they compare the numbers being recorded from past years. This data gives biologists a long-term view of the number of individuals and may show population increases or decreases.
  • What about the bald eagle in Iowa?
      • While many communities in Iowa celebrate the bald eagle with special viewing events, in many parts of the state we can see eagles every month of the year! Thanks to many public and private conservation agencies and concerned individuals, the bald eagle was removed from the federal endangered species list in 2007. See press release on American Eagle Foundation's website. Continued protections, the removal of harmful pesticides like DDT from the environment, and habitat protection and improvement all contributed to that historic event. 

    What is likely to help bald eagles and other raptors most in the coming years is the renewed interest surrounding "all things eagle." Folks want to learn about eagle natural history and biology, eagle habitat, and watch eagles down the road and on-line.  Come on, who hasn't heard about the Decorah eagle cam and D1?

    There are now eagles nesting in Iowa along every major river and in many Iowa counties. The Iowa DNR estimated that there were only 13 active nest in Iowa in 1991 and that in 2010 there were an estimated 250 active eagle nests in the state.  Eagle nests have been reported in 86 of Iowa's 99 counties.

  • Iowa DNR brochure Bald Eagles in Iowa
  • USFWS: Bald eagle life history and conservation success
  • Nature - American Eagle: This PBS produced, hour-long episode of Nature filmed by Neil Rettig shows the lives of eagles in the wild
  • Also, check out all the FAQs on the Journey North website about eagles here.


    Raptor Adaptations and Biology

    • How long does it take raptor eggs to hatch?
      • Incubation lasts 35-40 days. The first egg laid hatches first and the second egg hatches about four days later. If the third egg hatches, it will hatch four days after the second.
    • What are the stages of bird of prey development?
      • During the first few weeks after hatching, eaglets and other raptors are almost never left alone. Parents keep very busy taking care of them. One parent is always on the nest covering their babies with wings to keep them warm and to protect them from sun and weather. As the nestlings gain strength, they begin to wobble on their feet using wings like crutches. They are very clumsy. As they begin become bigger and stronger, they are much more steady and flap their wings and begin to "branch." Branchers test their skills by going to nearby branches and stay close to the nest. First flight usually occurs around 75 days after hatching and the bird a fledgling.
    • What is special about raptor feet?
      • Raptor feet are amazing. Eagles, falcons, and most hawks do not have feathers that cover their feet. Owls have fine, specialized feathers to cover their feet. The size, thickness, and curvature of the talons are matched to the bird’s hunting habits. Small falcons, like the American kestrel, have long and slender toes designed for perching and grasping and their talons are curved and needle-sharp. Ospreys have toes that are covered with spicules on the underneath side (like a Velcro feeling) to grasp slippery fish. Their outer toe is reversible, just like an owl’s, and their talons are tipped with long curved talons (fish hook style) that are sharp as needles. Eagle’s toes are short and powerful with long, strongly curved talons.
      • Check out this December 2009 post from "A DC Birding Blog" that helps to explain how raptor talons are matched to the prey!
    • Can an owl turn its head all the way around?
      • Owls can turn their head 270 degrees, that is about twice what you and I can do! They can do this because they have more vertebrae in their neck than humans.
      • How do owls spin their heads without tearing arteries? Read this NPR story about and check out the visuals for this college students science investigation.
    • Do osprey have special adaptations?
      • Ospreys, Pandion haliaeetus, are commonly called fish hawks or fish eagles but they are neither a true hawk nor eagle. The species is of ancient lineage presently classified near the Kite family. Osprey fossils show that they have been on earth for 13 million years. People have long admired the osprey's fishing skills and strengths, incorporating them into their cultures. Ancient Greeks thought an osprey could predict lightning. Asian emperors had osprey images woven into palace tapestries. In South America, native people used osprey feathers and bones in ceremonies to guarantee fishing success. In Canada, a Northwest Coast First Nation legend tells of a marriage between an osprey and a whale that created the orca whale. Orcas are large, black-and-white, and jump out of the water like a bird in flight and have a cry that sounds like an osprey.

        Ospreys pale bluish talons are tipped with nature's finest fishhooks; claws, sharp as needles - true fishing perfection. They can see five times more clearly than people, and just like bow fishermen, they must learn the ways of water's refraction of sunlight rays. Their outer toes, like those of owls, are reversible; these characteristics and sharp protuberances (spicules) on the lower surface of the toes allow them to grasp slippery fish. They catch prey with their feet with spectacular feet-first dives, entering the water completely, withstanding the 40-50 mph dive. Specialized joints at the wrist of the wing allow them to lift from the water, vertically. These anatomical tools they possess are what distinguish them from other raptors.


    Nests and Nest Building

    • Do birds reuse the same nest each year?
      • Some raptors will build on and reuse their nest year after year. Some birds do not build a nest, but will use abandoned nests or tree cavities. Some of our smaller songbirds will rebuild year after year because their nests get damaged between nesting times.
    • What materials do birds use when nest building?
      • Each bird group likes to use different material for their nest. Eagles, hawks, and osprey use sticks, corn husks, old cornstalks, roots, and mud. Songbirds like a variety of small sticks, grasses, and old plant material. Some will gather an animal’s fur that they leave behind to add into their nest for warmth and insulation. All species of birds have their own favorite materials that they will add into their nest each year.
    • What materials do Iowa eagles use in their nest?
      • The main things you see in an eagle nest are sticks! Some will bring back sticks that they find while soaring and hunting for their food. Sometimes, they steal sticks from beaver dams. Beaver dams have lots of sticks to choose from and it’s easier to let someone else do the hard work of finding and shortening sticks! You will see mud, grass, cornstalks, and corn husks woven in with the sticks. The bowl of the nest is usually lined with soft grass and plant materials. Eagles are always working to make their nest better and keep a clean house.

    Migration

    • Do all raptors migrate and where do they go?
      • In some species, like osprey, broad-winged hawks, and peregrine falcons, almost all of them migrate out of the US and Canada to Central and South America.
      • In some species, only some of the individuals migrate and the distance varies depending on food availability. A lack of food is the biggest reason that most hawks leave their breeding territory in the winter.
    • What do you call the path that birds use to migrate?
      • A flyway is the path that birds congregate along to travel. There are four major flyways in the US: Pacific Flyway, Central Flyway, Mississippi Flyway, and Atlantic Flyway.
    • Learn about fall bird migration in this radio interview from KNIA / KRLS from 8/15/2012
    • What types of migration patterns are there?
      • Neotropical migrants are birds that breed in North America, but spend the winter season south of the border in Mexico, Central America, South America, and the Caribbean. Some older folk may still call them “jungle birds.” A few examples would be blue-winged teal, oriole, tanagers, bobolink, grosbeaks, hummingbirds, and Swainson’s hawk.
      • Short-distance migrants are birds that winter south of their breeding grounds, but stay mainly within the United States and Mexico. Wrens, killdeer, red-tailed hawks, bald eagles, and white pelicans are examples.
      • Partial Migration is considered by some to be linked more to a “genetic code.” Some birds of the same specie will migrate while others will stay in the same area. Iowa examples include robins, bluebirds, goldfinches, chickadees, etc.  Some will migrate, while others tend to stay and bear our winters deeper into wooded protection. Iowa holds many flocks of robins all winter long, but come spring, large flocks of returning robins appear in our yards again returning from somewhere south.
      • Irruptions are usually a result of a food driven journey. Food sources of some birds can vary dramatically, season to season, year to year. Some would call this a “flexible” migration strategy. An example would be the snowy and saw-whet owls and other boreal birds that follow their significant food source. 2012 was considered an irruption year with the dramatic migration of young snowy owls moved into Iowa and even Missouri. Our environment here does not compare to their homeland in the tundra and many of those birds face huge mortality.
    • These terms are useful in understanding some of the different ways animals cope and survive winter:
      • Hibernation: A special kind of 'sleep' which is deeper and lasts longer than ordinary sleep. During hibernation the heartbeat and rate of breathing are much slower than when active, and the body temperature drops close to that of the surroundings. The true hibernator awakens slowly.
      • Torpor: A state of physical or mental inactivity; lethargy.
      • Estivation: A prolonged torpor or dormancy of an animal during a hot or dry period.
      • Migration: Seasonal movement from one place to another. (See previous FAQ)
      • Cold blooded: These animals require outside heat (like the sun to warm environment) to provide energy for movement and to sustain life. 
      • Warm blooded: Animals (chiefly mammals and birds) that maintain a constant body temperature typically above that of the surroundings; also called homoeothermic.
      • Dormancy: Normal physical functions suspended or slowed down for a period of time as if in a deep sleep, e.g. mourning cloaks, red admiral, painted lady butterflies.

    Cultural Significance
    • When did the bald eagle become our national symbol and why?
      • On 20 June 1872 our Continental Congress (as it was called then) selected the bald eagle as our national symbol because of the bird's symbolic power, strength, and freedom. Yes, Thomas Jefferson did suggest the wild turkey be the national symbol.

    Laws

    • Are eagles protected by any laws?
      • Lacy Act Amendments of 1981 - updated the Lacey Act of 1900 and protects bald eagles by making it a Federal offense to take, possess, transport, sell, import, or export their nests, eggs and parts that are taken in violation of any state, tribal or U.S. law.
      • Post De-Listing Monitoring Plan - this plan is a requirement of the Endangered Species Act and includes nest monitoring every 5 years, starting in 2009, continuing for 20 years.
    • Who makes wildlife laws?
      • State laws, including wildlife laws, are proposed and voted on by the Iowa Legislature. Approved laws are then sent to the Governor for final approval or veto. The Natural Resources Commission of the Iowa Department of Natural Resources sets seasons, hunting dates and method of take for Iowa wildlife. The U. S. Fish and Wildlife Service is a Federal agency that has specific laws of their own that work along with specific State Laws. For example: All birds in Iowa are protected by Iowa law, except for the English sparrow and the European starling. If someone were to shoot or injure a songbird, raptor, etc., both state and federal laws would apply. The Migratory Bird Treaty Act of 1918 - protects migratory birds and any part, nest, or egg of any such bird, except as allowed for by specific law (like duck and goose hunting, in which those rules and regulations are also specific to the resource).
    • Who enforces wildlife laws?
      • In Iowa, the Law Enforcement Bureau within the Iowa Department of Natural Resources is responsible for natural resources law enforcement. Specifically, a Conservation Officer is the person that you will see out and about providing enforcement and public safety. Conservation Officers are certified peace officers and able to enforce ANY and all Iowa laws. You might hear them called a "Game Warden." Visit the Iowa DNR website to learn about what a conservation officer does! In Iowa, there is less than one conservation officer per county to enforce Iowa’s fish and game laws. There are also Federal Fish and Game Officers that are employed by the U. S. Fish and Wildlife Service, within the U.S. Department of the Interior. The Federal Fish and Game Officers work on a state level and authority can also take them out of the country.

    Lead Awareness
    • Where can lead be found?
      • Lead is a highly toxic metal found in small amounts in the earth’s crust. Because of its abundance, low cost, and physical properties, lead and lead compounds have been used in a wide variety of products including paint, ceramics, pipes, solders, gasoline, batteries, and cosmetics. Since 1980, federal and state regulatory standards have helped to minimize or eliminate the amount of lead in consumer products and occupational settings. Today, the most common sources of lead exposure in the United States are lead-based paint in older homes, contaminated soil, household dust, drinking water, lead crystal, and lead-glazed pottery. While extreme lead exposure can cause a variety of neurological disorders such as lack of muscular coordination, convulsions and coma, much lower lead levels have been associated with measurable changes in children’s mental development and behavior. These include hyperactivity; deficits in fine motor function, hand-eye coordination, and reaction time; and lowered performance on intelligence tests. Chronic lead exposure in adults can result in increased blood pressure, decreased fertility, cataracts, nerve disorders, muscle and joint pain, and memory or concentration problems. Information taken from the National Institute of Environmental Health Science
    • How has lead been used in the past?
      • Questions arise about the downfall of the Roman Empire and if lead was the cause of the Empire to fall. There will always be questions about this, and it looks as though there is much debate. One thing is known, and that would be that the discovery of lead was around 3500 BC. Well-to-do Romans painted their walls a rich Pompeian red, which owed its color to a salt of lead or mercury. Lead was used for water pipes, cups, toys, statues, cosmetics, coffins, and roofs, but the most significant source may have been the wine of the wealthy class.
    • Is lead safe?
      • Many different agencies regulate lead according to scientific research and the products and health issues they control. Some of the agencies that you can contact for information would include The United States Environmental Protection Agency, The Food and Drug Administration, Consumer Product Safety Commission, and the Centers for Disease Control.
    • Can lead make me sick?
      • While extreme lead exposure can cause a variety of neurological disorders such as lack of muscular coordination, convulsions and coma, much lower lead levels have been associated with measurable changes in children’s mental development and behavior. These include hyperactivity; deficits in fine motor function, hand-eye coordination, and reaction time; and lowered performance on intelligence tests. Chronic lead exposure in adults can result in increased blood pressure, decreased fertility, cataracts, nerve disorders, muscle and joint pain, and memory or concentration problems. Information taken from the National Institute of Environmental Health Science
      • ToxFAQs for lead available from the Agency for Toxic Substances Disease Registry
    • Can lead make an animal sick?
      • Lead is in our earth. It will not ever go away. We can become responsible and knowledgeable about lead, its common uses in our recreational activities within the environment (lead sinkers, lead ammunition, etc), and learn more about the effects of lead on our wildlife. Lead toxicity in bald eagles causes tremors, seizures, muscle impairment, vision issues, and more. A lead-affected eagle will have trouble breathing, will have difficulty standing, holds their wings out, and becomes uncoordinated and because of these issues often suffers other trauma like flying into trees, poles, power lines, or being hit by a vehicle.
      • See SOAR - Saving Our Avian Resources for research being done about how lead impacts eagles and other birds and to learn more about hunting lead-free.
    • Where can I learn more about the risks to humans and wildlife of ingesting lead?

    Raptor Rehabilitation
    • What happens to sick or injured raptors?
      • Adult raptors have few predators. Most of their injuries are a result of human influence – like a collision with a car or a power line, removing the bird’s habitat or nesting tree, scavenging for food that contains something poisonous to the bird, or by being shot. Some raptors will die of natural causes. Many of the injured birds are already in a critical condition when found or noticed by people. There are licensed facilities and individuals that will try to nurse them back to health. Rehabilitators are not paid by any natural resource agency. They rely on grants and donations.
    • Are there raptor rehabilitation centers in or near Iowa?
    • What should I do if I find an injured raptor in Iowa?

    Other Bird Questions
    • Check out this FAQ page, too!
    • How do birds fly?
      • The birds that can fly do so because their bones are hollow with bony supports across the bone’s diameter for support. This greatly reduces the weight of the bird. Feathers are light in weight and the pattern of feathers on a bird allows the tail and wings to utilize air flow to their advantage. Add in the large muscles in the breast and across the back that help power the wings and you can have sustained flight. Larger and heavier birds like eagles and some hawks, have long, broad wings that enable them to make use of rising air currents (such as winds that rise off of slopes or hot air thermals). These birds can soar for long periods of time. Some birds are built for speed, they have broad wings and long tails that give them lift and can move like an acrobat in flight (accipiters like Cooper’s hawks and sharp-shinned hawks). Some birds have long, narrow wings and muscular bodies built for high-speed aerial maneuvers and can use their long tails to help them hover in one place above the ground (falcons).
    • How do we know the health of bird populations?
      • There are organizations in Iowa that assist with the volunteer monitoring of bird populations that can help professionals; two would be Iowa Audubon Society and Iowa Ornithologists Union. These groups work along with the Cornell Laboratory of Ornithology and the National Audubon Society for some of their birding events. People, just like you, volunteer their time to help document bird activity with Project Feeder Watch, the Great Backyard Bird Count, or participate in the Christmas Bird Count. The information gathered from these events comes from across the United States and are tallied. This information is available to conservation agencies and the U.S. Fish and Wildlife Service. The Iowa Department of Natural Resources also has a volunteer monitoring program for bald eagles and their nesting areas and assists with the Breeding Bird Atlas. The Iowa DNR and other professionals participate in the Mid-Winter Waterfowl and Eagle Count Survey in which these numbers are recorded and sent into the U.S. Fish and Wildlife Service and numbers are compared to previous years.
    • Are red-tailed hawks to blame for low pheasant numbers?
      • It's all about habitat -- both quantity and quality. Weather impacts upland game populations from year to year -- after a severe winter followed by a wet spring, the conditions are not optimal for successful nesting. According to the 2011 Iowa DNR August Roadside Survey, "This marks the 5th consecutive winter in a row Iowa has received ~ 30 inches or more of snowfall. In the 50 yrs of standardized roadside counts Iowa has never seen 5 consecutive winters of this severity."

        Habitat loss is gradual and is best noted over time. US Department of Agriculture estimates that over 2,400 square miles of small grains, hay ground, and CRP has been converted to soybeans and corn between 1990 and 2005.

        Click here for the complete DNR August Roadside Survey.

        Besides, did you know that 75% of red-tailed hawk's diet is made up of small mammals like rabbits, mice, rats, and ground squirrels?

        Download a 2-page PDF on how raptors help "keep the balance."
    • Want to learn more about eagle species from around the world?
      • Check out the Eagle Directory! The Eagle Directory is dedicated to providing accurate information about eagles from around the world!
    • How fast can a peregrine fly?

    Falconry