The Dark-eyed Junco (Junco hyemalis) is a widespread songbird across North America, often appearing in backyards and woodlands from coast to coast. This small, grayish sparrow is highly adaptable, which allows it to thrive in diverse environments. The junco’s ability to survive is directly linked to its varied diet, which changes significantly depending on local availability and the demands of the season. This flexibility makes the junco an opportunistic omnivore, shifting its focus between plant matter and animal protein throughout the year.
Primary Natural Diet
Juncos primarily eat seeds and arthropods, though plant matter generally dominates their diet throughout the year. The majority of their food comes from small seeds, primarily those of grasses and common weeds, which they forage for on the ground. Preferred wild foods include the seeds of ragweed, chickweed, goosefoot, crabgrasses, and dropseed grasses.
They also find fallen grains in open areas and supplement their diet with small, native berries when available. Adult juncos typically consume a diet that is approximately 75% plant-based food items during the non-breeding season. This reliance on durable seeds ensures a stable energy source when other food types are scarce.
The animal portion of the junco’s diet consists of invertebrates, collectively known as arthropods. Juncos actively seek out small beetles, grasshoppers, spiders, and insect larvae, such as caterpillars. These protein-rich items are especially important for providing the necessary nutrients for the birds’ general health and during periods of increased physical activity.
Seasonal Dietary Shifts
The junco’s diet shifts between warm and cold months, driven by nutritional requirements for breeding and survival. During the spring and summer breeding season, the need for protein increases sharply to support nesting and the rapid development of young birds. Adult juncos increase their intake of insects and other arthropods, which can comprise nearly half of the adult bird’s diet.
This protein is vital for nestlings, as junco chicks are fed a diet consisting almost exclusively of insects and invertebrates. This specialized feeding ensures the young receive the high levels of fat and protein required to grow quickly and fledge only 9 to 13 days after hatching.
In the fall and winter months, the junco’s diet leans heavily toward seeds and grains for energy and insulation. Arthropods become scarce, and the birds rely on high-carbohydrate, high-fat plant matter to maintain their body temperature. Wintering juncos are often seen in flocks, foraging for dense seed patches that can sustain them through the season.
Preferred Feeder Foods and Foraging Habits
Juncos exhibit distinct preferences for certain commercial seeds that mimic the small wild seeds they naturally consume. Their favorite feeder food is typically white proso millet, which is small and easy to manage. They also readily consume cracked corn and hulled sunflower seeds, the latter providing a high-oil, high-energy boost during the winter.
Juncos are primarily ground-feeding birds. Unlike many songbirds that perch on hanging tube feeders, juncos prefer to forage on the ground directly beneath a feeder, picking up scattered seeds. They also readily use low platform feeders, as these mimic their natural ground-level foraging environment.
A key foraging behavior is the characteristic “scratching” motion they use to uncover buried food. Juncos hop forward and backward, using both feet simultaneously to sweep away leaf litter, snow, or debris, exposing seeds and dormant insects. This method is effective in winter when snow covers potential food sources, allowing them to access grains that other birds cannot reach.