How can you tell if a bald eagle is young?

Bald eagles are majestic birds of prey found throughout North America. They are the national bird of the United States and hold significance in many Native American cultures. Bald eagles have distinctive brown bodies and bright white heads and tails, which develop as they mature. Young bald eagles look quite different than mature adults. There are some key ways you can identify juvenile bald eagles.

Plumage

The most obvious difference between adult and young bald eagles is their plumage or feather coloring. Young bald eagles have mostly dark brown feathers on their bodies. Their heads and tails are mottled patches of white and brown. Bald eagles do not develop their full white heads and tails until they are 4-5 years old. The process of transforming from a dark brown juvenile to the iconic white-headed adult is visible as the bird matures over several years. Here are the key plumage differences between age classes:

Hatchlings

Newly hatched bald eagle chicks are covered in fluffy down. They are a grayish-white color all over.

Fledglings

Young eagles leave the nest at 10-13 weeks. Fledgling plumage is mostly dark brown, with some white mottling especially on the wings and tail. The beak and eyes are dark at this stage.

Immatures

In their first year after leaving the nest, immature bald eagles have mostly dark brown plumage with variable white mottling on the head, chest, wings and tail. The beak begins lightening to a yellowish hue.

Subadults

In years 2-4, subadult eagles’ plumage progressively lightens. The head and tail gain more white feathers each year. The beak becomes pale yellow. Some subadult eagles may still show many brown feathers while others appear nearly fully white-headed.

Adults

After 4-5 years, bald eagles finally achieve the iconic white head and tail with dark brown body plumage. The beak is bright yellow at this mature stage.

Behaviors

Young bald eagles also behave differently than mature birds in some recognizable ways:

• Fledglings may still be working on flying skills and staying close to the nest.
• Immatures and subadults are reliant on parents for feeding and protection.
• Juveniles have less confident flight patterns than adults.
• Young eagles are less skilled at hunting than adults.
• Juveniles may scavenge more frequently than adults who are better at hunting.
• Young birds are louder and more vocal, especially demanding food.
• Juveniles lack the prominent white tail of adults, making their outline look different in flight.

Size

Younger bald eagles are also smaller on average than mature adults. Some size differences:

Facial Features

Some facial characteristics also help distinguish young bald eagles from adults:

• Beak color – Young eagles have dark beaks that gradually lighten to yellow as they mature.
• Eyes – Juvenile eagles have darker eyes while adult eyes are pale yellow.
• Plumage – The heads of young eagles are dark brown or mottled white and brown.

All of these facial features slowly transition to the distinctive adult appearance of a bright yellow beak and eyes with full white head feathers.

Voice

The vocalizations of bald eagles differ among age groups. Young bald eagles make louder, higher-pitched cries than adults. Their classic scream is more grating than the deep croaking chirps of mature eagles. Juveniles may frequently scream when demanding food while adult vocalizations are more varied. Eagles make other sounds like barks, clicks, whistles and yelps. With practice, you can discern the subtler voices of older bald eagles.

Habitat

Where you observe a bald eagle can also indicate its age:

• Young eagles stay close to the nest for weeks after hatching and fledge from the nest tree.
• Immature and subadult eagles are often found near water where their parents fish.
• Adult bald eagles occupy established territories and nesting sites.
• Juveniles may congregate together in late summer and migrate separately from breeding adults.

The habitat where an unknown eagle is spotted provides clues about whether you’re seeing an adult pair on territory or a recent fledgling.

Time of Year

The season when you see a bald eagle also affects the probability that it is a juvenile. Here is a guide:

• Eagles hatch from April to early June.
• Fledglings leave the nest from June to August.
• Immatures and subadults may migrate and winter separately from adults.
• By November and December, most young eagles have migrated from breeding areas.
• Young eagles are most likely to be seen in summer and fall.
• Adults are present year-round in non-breeding range.

If you spot an eagle from October to March, it is very likely a white-headed mature adult. Seeing an eagle from June to September increases the odds you have found a brown-bodied juvenile on its journey to adulthood.

Identification Tips

Here are some quick tips for distinguishing young bald eagles from adults in the field:

• Brown body and white mottled head/tail – juvenile
• Mostly dark beak – juvenile
• Smaller size – juvenile
• Uneven flight – juvenile
• Near nest – likely juvenile
• Loud screaming call – juvenile
• With parent – juvenile
• White head/tail – adult
• Yellow beak – adult
• Large size – adult
• Confident flight – adult
• On territory – adult
• Summer/Fall – more likely juvenile
• Winter – likely adult

Conclusion

Telling a young bald eagle apart from a mature adult requires looking at several key characteristics beyond just plumage coloration. The beak, eyes, vocalizations, behaviors, flight ability, size, habitat and time of year all provide clues about the age of a bald eagle. With practice, bird watchers can quickly learn to differentiate between age classes in the field. Understanding how to identify juveniles correctly allows you to follow the gradual maturation process as the eagles grow into their iconic white-headed adult form over several years. Being able to distinguish young bald eagles aids research and conservation efforts for this special bird.