The Dickcissel is a small songbird found in grasslands and agricultural fields across central North America. Measuring 15–18 cm in length and weighing 18–27 g, it is a rather plain bird with a grey face, yellowish breast, and dark grey wings. But what the Dickcissel lacks in colorful plumage, it makes up for with its loud, distinctive song. The male sings a melodic “dick dick” song from elevated perches during the breeding season to establish its territory and attract females.
Dickcissels are primarily seed eaters, feeding on the seeds of grasses, sedges, and forbs. During the breeding season, they mainly eat insects to get the protein they need to raise their young. The diet of a Dickcissel can provide insight into its habitat needs and the health of grassland bird populations.
Seeds
Seeds make up the bulk of the Dickcissel diet, comprising over 60% of their annual food intake. They have a thick, conical bill that is well-adapted for cracking open seeds. Dickcissels glean seeds directly off the stems of grasses and forbs or pick them up from the ground. Some of their commonly consumed grass seeds include sorghum, millet, wheat, and crabgrass. They will also readily eat the small seeds of legumes, lettuce, amaranth, dandelion, and other forbs.
Dickcissels prefer to forage for seeds in native grasslands, pastures, hayfields, idle fields, roadsides, and crop fields after harvest. They search for food while walking along the ground or making short flights to scatter and flush insects. The availability of suitable grass and forb seeds influences both breeding and migratory habitat selection in Dickcissels.
Insects
Although seeds are their primary food source, insects become an important part of the Dickcissel diet during the breeding season from May to August. At this time, they switch their diet to be over 50% insects to get the protein and nutrients needed to produce eggs and raise nestlings. Some common insects consumed include beetles, grasshoppers, crickets, caterpillars, ants, wasps, and dragonflies.
Adult Dickcissels capture flying insects on the wing by aerial hawking. They glean larvae, eggs, and dormant insects off vegetation and will occasionally probe into the soil. Chicks are fed almost exclusively insects for their first week until they are able to self-feed on seeds. The availability of insects influences nest site selection and reproductive success in Dickcissels.
| Food Type | Examples | Importance |
|---|---|---|
| Seeds | Grasses, forbs, agricultural grains | Primary food, needed year-round |
| Insects | Beetles, grasshoppers, caterpillars | Essential food for breeding |
Foraging Habits
Dickcissels have adapted their foraging strategy to the seasonal availability of seeds and insects. In the non-breeding season, they mainly glean seeds from grasses, residual crops, and weed patches. While breeding, they expend more energy flying to capture insects on the wing over wider areas.
They primarily forage on the ground, searching for food while walking. Occasionally they will cling to grass stems or make short fluttering flights to kick and scatter material to uncover hidden food. Dickcissels will also hawk flying insects from low perches 1-4 m off the ground. They typically forage close to cover where they can quickly escape from predators.
Dickcissels are social foragers and form large flocks outside of the breeding season. They will congregate in favorable feeding sites, especially crop fields where waste grain is abundant after harvest. Up to several hundred birds may forage together in these aggregations.
Water
While they get most of their moisture from seeds and insects, Dickcissels also need to drink water regularly. Ornithologists observe them drinking water from rain puddles, wetlands, streams, and farm ponds, usually in the early morning and evening. They bathe in shallow water to clean their feathers and will visit saucer-shaped depressions in the ground called bird baths.
Habitat
The diet of Dickcissels is closely tied to its habitat needs. Originally a prairie species, Dickcissels thrive in open grassy areas with moderate vegetation height and density. Native prairies and pastures provide an abundance of grass and forb seeds. Hayfields, old fields, and native grasslands supply insects for breeding. Ideal habitat has a combination of bare ground for foraging, low vegetation for nesting, and scattered shrubs or fences for singing perches.
They readily use agricultural areas, especially small grain fields and row crops. Waste corn and cereal grains left after harvest provide a critical winter food source. While breeding, nests are built along field edges to allow access to insect prey. Conservation of grasslands, pastures, and untilled field margins benefits Dickcissel populations.
Range and Population Trends
Dickcissels have experienced population declines due to extensive loss and degradation of native grasslands. They were once restricted to prairie regions, but expanded eastward into croplands in the 1800s following forest clearance. Highest numbers now occur in the Midwest agricultural belt.
Dickcissel populations dropped significantly in the late 1900s, estimated to have declined by 60% between 1966 and 2015, according to the North American Breeding Bird Survey. These declines have been attributed to habitat loss, pesticide use, changing cropping practices, and mismanagement of grasslands. Conservation practices such as prescribed fire, grazing, and hayfield management can improve habitat quality for Dickcissels.
Ecological Role
As grassland songbirds, Dickcissels play an important role in grassland ecosystems. They influence plant reproduction and seed dispersal as they forage on seeds and grains. Their abandoned nests provide habitat for other wildlife. Dickcissels contribute to insect population control as they consume pest species such as grasshoppers and cutworms. They are also prey for small carnivores, raptors, and snakes.
Dickcissel numbers can indicate the health of grassland habitats. Declines may signal degradation from invasive plants, overgrazing, fire suppression, or agricultural practices. Monitoring Dickcissel populations over time provides an assessment of sustainable land management practices.
Unique Adaptations for Diet
Dickcissels have several key adaptations that allow them to thrive on a seed and insect diet:
- Conical bill shape to crack into seeds
- Ability to digest complex plant carbohydrates
- Increased insect consumption while breeding
- Ability to glean small insects from foliage
- Gizzards to grind up food items
- Fat deposits to fuel migration and survive cold winters
- Social foraging behavior
Conclusion
In summary, Dickcissels are specialized grassland birds that mainly eat seeds and insects. Seeds of native grasses, forbs, and agricultural grains provide their primary energy food source. Insects like beetles and grasshoppers are an essential food for breeding. Their conical seed-cracking bill, fat stores, and digestive system allow them to subsist on this diet. Dickcissels require a habitat mosaic that provides both open areas for foraging on the ground and adequate cover for nesting. Their populations are declining due to habitat loss, indicating degradation of prairie and farmland ecosystems. Understanding the dietary needs and foraging ecology of grassland birds like the Dickcissel can guide conservation efforts.
