Did You Know?
During the winter, sage grouse live only on sagebrush leaves – 99 percent of their diet. In the other seasons, the birds will eat insects and forbs, too, but after the first frost hits they lose those tasty items. Just as a panda bear can’t live without bamboo shoots, the sage grouse can’t survive without sagebrush.
Foods for every life stage and season
To appreciate the special diets of sage grouse takes looking at what they need in different stages of life – from chick to adult; seasonal variety; and specific foods that hens must eat prior to laying. Sagebrush is an essential component of their diet – but it’s not the only requirement. Throughout the year, the birds nip the leaves off of plants, and will also feed on buds, flowers, fruits and insects.
Early Summer: Chicks Need Insects
Within a couple days of hatching, chicks are following hens looking for insect-rich foods. In the first three weeks, ants and beetles especially provide juveniles the protein they need to survive and grow at this critical stage.
Late Summer: Juveniles Add Forbs (broad-leaved herbaceous plants)
As the chicks grow, they branch out from insects to add forbs to their diet and gradually add sagebrush. They eat a higher percentage of forbs than adults. An Oregon study in 1994 found that diets of sage grouse young included an impressive 34 genera of forbs and 41 families of invertebrates.
As sagebrush habitats dry out, adults and juveniles make their way to wetter sites where they can dine on forbs as well as sagebrush. They may feed in small burned areas within sagebrush, wet meadows, hayfields and other irrigated areas.
Fall: Adults/Juveniles Start to Shift to Sagebrush Diet
From late August to December most sage grouse are meandering toward their winter range – places with less snow and plentiful sagebrush for food and cover. Most birds have left their summer ranges by October. En route, the birds take advantage of a variety of sagebrush grassland habitats.
Winter: Sage Grouse Eat Sagebrush – in several varieties
Usually by early October, sage grouse have left their summer areas. As they move toward their winter ranges, they start a transition from a lot of forbs in September to strictly sagebrush by December.
Sagebrush leaves make up the entire diet of sage grouse in winter. In most places, they’re feeding on big sagebrush. In some places, they prefer Wyoming big sagebrush and in others mountain big sagebrush. When available, they’ll also nip the leaves of low sagebrush, black sagebrush, fringed sagebrush, and silver sagebrush. The preferences may be tied to higher levels of protein and volatile oils in certain kinds of sagebrush.
Spring: Pre-laying Hens Need Calcium, Phosphorus and Protein
The onset of courtship and breeding season marks another diet shift for females that will be mating and then laying eggs. The pre-laying hens seek out forbs that are high in calcium, phosphorus, and protein. Their success with nesting and clutch size is closely tied to nutrition.