Eagle Diet by Season: A Year-Long Feeding Behavior Guide

I Documented Eagle Diet for a Full Year — The Seasonal Shift Shocked Me

January. April. July. October. These are my four observation checkpoints each year, and I have kept detailed feeding records at each one for the past three years. The differences in eagle diet between seasons are not subtle. They are dramatic, fascinating, and — in ways I am still learning — indicators of broader ecosystem health.

Winter Diet (November–March): The Scavenging Season

Winter is when eagle diet is most unusual — and most opportunistically scavenged. Fish become harder to catch as lakes freeze and rivers run with ice. Waterfowl migration is in full swing, making weakened or juvenile birds available. And deer die of cold and starvation throughout the winter range, providing abundant carrion.

Winter observation findings from my three-year study:

• 65–75% of observed feeding events involved carrion (deer, elk, and bison carcasses)
• 15–20% involved waterfowl (primarily injured or juvenile birds)
• 10–15% involved fish (largely near open water: dams, thermal outlets, fast-running streams)
• Scavenging behavior increased dramatically during cold snaps

Spring Diet (April–June): The Protein Rush

Spring is the most protein-intensive season in an eagle’s life — and the most active hunting season. Breeding eagles need fat reserves for egg production and incubation fasting. Growing nestlings need enormous quantities of protein. The spring eagle diet is dominated by the most nutritionally valuable prey available.

Spring is when fish availability peaks — spawning runs provide abundant, easy-to-catch prey. Waterfowl are also abundant as migration continues. I have documented spring eagle diet as being approximately 55–65% fish, 20–30% waterfowl, and 10–15% small mammals.

One of the most memorable feeding events I have ever witnessed: watching a female bald eagle bring a full-grown Canada goose to her nest for her two nestlings. The power required to carry a goose that size — at least 7 pounds, nearly half her body weight — was extraordinary. She landed in the nest barely able to hold on, and fed both nestlings for 45 minutes.

Summer Diet (July–August): The Fledgling Teaching Period

Summer is when eagle diet becomes chaotic and entertaining. Fledglings are learning to hunt — and they are comically bad at it. I have watched fledgling eagles attempt to catch fish in water so shallow the fish simply swam away, miss strikes on frogs at point-blank range, and stumble into water while trying to land on floating logs.

Adult eagles during summer are simultaneously feeding themselves, feeding fledglings, and teaching hunting skills. Diet diversity peaks during summer: frogs, turtles, crabs, small mammals, insects, and fish all feature prominently. Summer is when I have observed the widest variety of prey items in eagle diets.

Fall Diet (September–October): Migration Preparation

Fall is when eagles enter a behavior called hyperphagia — a period of intensive feeding to build fat reserves before migration or winter. During hyperphagia, an eagle may consume up to twice its normal daily food intake, packing on fat that will sustain it through migration or winter food scarcity.

Fall also brings a second waterfowl migration, spawning salmon runs in Pacific coast and Great Lakes tributaries, and abundant carrion from hunting season deer mortality. Fall is arguably the best season for eagle observation — they are most active, most visible, and most likely to be hunting in open habitats where you can observe them.

The Pain Points of Seasonal Diet Observation

The biggest challenge I have faced in documenting seasonal diet variation: identification. Every season presents identification challenges that the others don’t. Winter eagles are harder to observe due to shorter daylight hours. Summer eagles are obscured by foliage. Spring requires navigating muddy, flooded riverbanks. Fall requires climbing hillsides for ridge observation.

The most frustrating mistake I made: assuming that because I saw a bald eagle eating a rabbit in February, rabbit was now part of its regular diet. It wasn’t. It was a winter anomaly — a scavenging event from a road-killed rabbit. Species-typical eagle diet and individual opportunistic eating events are very different things. The distinction matters enormously for accurate observation.

Frequently Asked Questions

Do eagles migrate to find food?
Some do. Northern populations of bald eagles often migrate south to find open water in winter. Southern populations may be year-round residents. Golden eagles in western North America have complex migration patterns tied to altitude and prey availability, with some individuals migrating and others remaining resident.

Do eagles eat more in summer or winter?
Per feeding event, eagles eat more in winter (larger meals to build reserves). Total food consumption over the entire season is typically higher in summer, when active growing nestlings create enormous demand.

What do eagles eat in desert regions where there is no water?
Golden eagles in arid western habitats primarily eat mammals — jackrabbits, ground squirrels, and prairie dogs make up the vast majority of their diet. They obtain water primarily from their prey and are remarkably drought-adapted.