Welcome! See – Learn – Share. Our galleries document the variation of bald eagle plumage across the pre-definitive molt sequence (age), individuals, regions and seasons. In most cases, these variables aren’t known, so plumage and age classifications are approximate, based on plumage presentation and coloring of the beak, cere and iris. Sorting of the images is also approximate based upon Mark A. McCollough’s seminal 1989 paper, “Molting Sequence and Aging of Bald Eagles” which includes his descriptions and iconic sketches of known-age individuals. The variation in plumage tells a story of molt sequence over time. This page is dedicated to the Basic I plumage class which begins at about 1 ½ years of age, marking the completion of the Prebasic I molt. Please refer to the table below the gallery for key classification tips. A full plumage description is available in McCollough’s cited paper. Some individuals shown in this gallery may reflect active molt. They are placed in the gallery that best matches their overall presentation based on McCollough’s 1989 plumage descriptions. Viewer input is welcome.
(andy morffew / andymorffew com / cc by 20)
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Eagles Explored Bald Eagle head diagram
(dan logan / flickr / cc by nc 20)
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(don mccrady / flickr / cc by nc nd 20)
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(dagny gromer / flickr / cc by nc nd 20)
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(earl bye / flickr / cc by 20)
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(maskirovka77 / flickr / public domain)
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(alice belthoff / pexels / pexels license)
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(andy morffew / andymorffew com / cc by 20)
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(dagny gromer / flickr / cc by nc nd 20)
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(earl bye / flickr / cc by 20)
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(frank cone / pexels / pexels license)
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(maskirovka77 / flickr / public domain)
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(maskirovka77 / flickr / public domain)
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(richard lee / byzgo6c tpz / unsplash)
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(richard lee / unsplash / unsplash license)
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(frank cone / pexels / pexels license)
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(frank cone / pexels / pexels license)
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(andy morffew / andymorffew com / cc by 20)
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(jackbulmer / pixabay / pixabay license)
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(susan young / flickr / public domain)
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(dan logan / flickr / cc by nc 20)
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(becky matsubara / flickr / cc by 20)
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(maskirovka77 / flickr / public domain)
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(maskirovka77 / flickr / public domain)
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(maskirovka77 / flickr / public domain)
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(mathew schwartz / unsplash / unsplash license)
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(terra raponi / unsplash / unsplash license)
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(the back road photographer / flickr / cc by 20)
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(usfws alaska region / flickr / public domain)
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(usfws midwest region / flickr / public domain)
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(usfws mountain prairie / flickr / public domain)
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(andy morffew / andymorffew com / cc by 20)
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(andy morffew / andymorffew com / cc by 20)
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(hunter masters / unsplash / unsplash license)
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(bob wild / pexels / pexels license)
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(jerry mcfarland / flickr / cc by nc 20)
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(matt zimmerman / flickr / cc by 20)
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(rbird77 / pixabay / pixabay license)
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(usfws forensic lab / usfws / public domain)
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(usfws forensic lab / usfws / public domain)
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This anatomical diagram of the Bald Eagle’s head highlights key feather regions and structural features referenced in McCollough’s 1989 plumage study. While McCollough sometimes used accessible terms like “cheek,” “forehead,” and “eye stripe” to describe variation across plumage stages, this illustration offers a more detailed map of the underlying anatomy—including the auriculars, malars, crown, and throat. By visualizing these regions, viewers can better understand how flecking, shading, and molt-phase traits appear in different plumage classes. The diagram serves as both a reference and an invitation: to look closer, ask questions, and engage with the archive as a living resource. (Illustration Credit: EaglesExplored.com CC-BY-NC 2.0)
🦅 Basic I Plumage Identification Summary (1½ year) per Mark A. McCollough (1989). The following descriptions are based on McCollough’s observations of 135 Bald Eagles of known age. The observations were made in Maine and the Canadian Maritime Provinces. Plumage variation from these descriptions is possible, and rather likely based on factors such as season, region, molt status, diet, and more. This is a tool for approximation, not for confirmation. Some birds are undoubtedly in molt phase. An attempt has been made to place them in the gallery of the closest plumage classification. Please see note below gallery.
Feature
Description (per McCollough 1989)
Crown
Tan; noticeably lighter than juvenal crown, sharply contrasting with auriculars
Nape
Not explicitly described; inferred to be darker than crown, possibly brownish-olive
Auriculars
Blackish-brown; strong contrast with lighter crown
Chin/Throat
Not directly described; likely similar to crown or auriculars
Belly
Extremely variable; ranges from dark brown to nearly pure white; breast always darker, forming a “bib”
Tail
Dark-tipped rectrices; somewhat lighter than juvenal plumage; outer rectrices more rounded than blunt-ended juvenal feathers.
Beak
Predominantly blackish-gray; 30 birds showed buffy-yellow at base near cere or curve of beak
Cere
Blackish-gray; buffy-yellow interior and lining of nares
Iris
Buffy-brown in most; one bird had light cream iris typical of Basic II
Plumage Classification Note: Bald Eagle images in this archive have been sorted according to plumage stages described by McCollough (1989). With over 300 images and countless individual variations, some classifications may be imperfect or open to interpretation, especially in cases of transitional molt or atypical feathering. Molt-phase birds are placed in galleries that best reflect their overall appearance, though some may straddle two plumage stages both before and after the molt. This project is a work in progress, and constructive input is always welcome. If you believe an image might better reflect a different plumage stage—or if you notice traits that suggest molt phase rather than a clean classification, then please let us know. We’ll do our best to annotate transitional birds in their captions and move them to better-fitting galleries when appropriate. To share your thoughts, just refer to the image ID (e.g., EaglesExplored_00017) and reach out through the contact link. Your insights help us refine the archive and deepen the conversation.
