by Pat Jaquith
pat@westvalleynaturalists.org

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Juniper is a woody plant that provides habitat and food for a number of bird and animal species year ’round. For more information about local Juniper species and the wildlife that utilize them in all seasons, read on.

Common Juniper (Juniperus communis) in the Cypress family (Cupressaceae) is the most common species that we see here in the West Valley. This low-growing shrub with long, springy branches, prickly needles, and small oval-shaped cones with a waxy covering often grow in soils that have low nutrient levels such as old, over-grazed pastures. The dense ground cover of junipers is protective of young tree seedlings that might be subject to browse by ungulates. As the trees grow and make shade, the junipers die out from a lack of sunlight. This succession from pasture to forest is a long, gradual process, and in the meantime, the Junipers provide food and protective cover for many creatures.

In spring, Common Junipers produce unobtrusive blossoms that I rarely notice unless I’ve disturbed the branches, sending up a cloud of pollen. The blossoms become cones that take up to two or more years to mature. Often mistaken for berries, the little cones have 3 to 6 scales, each concealing a single seed. Birds digest the fleshy scales and pass the hard seeds in their droppings. It is reported that seeds that pass through a bird’s digestive tract have a greater germination rate.

Turkeys left a clue that they had been feeding on the berries of a Common Juniper 11.21.23, and on a frosty November morning, Bowser Lake was a bowl of fog that coated the Common Juniper with ice without harming it.

Townsend’s Solitaires and Robins are often found in areas where Junipers grow. The cones appear to be their major diet in winter and spring before the ground thaws.

Red Squirrels harvest Common Juniper cones, foliage and all, and carry them to their cache for consuming in winter. Above 11.02.26 . . . . It was running down the path ahead of me 8.18.26

Three male Pine Grosbeaks surprised me on 10.30.26 as they hopped around in the Common Juniper near the trail I was following. They were not shy about letting me watch them harvest and masticate the ripe dark-colored cones.

Rocky Mountain Juniper (Juniperus scopularum) is a small tree with grayish-green overlapping leaves that resemble Cedar. There are separate male and female plants: male plants have pollen-bearing cones; female cones are berry-like with a grayish bloom. They will mature in 2 years into dark blue-purple cones bearing 2 seeds. The seeds cannot germinate until the fleshy covering is removed – a task often accomplished by birds or mammals when they pass through their digestive tract.

Migrating birds sometimes stop in the West Valley to refuel on their way north where they will nest and eat insects. I happened to spot a flock of these warblers in a clump of Rocky Mountain Junipers and Hawthorn trees. They were feeding on the Junipers and warming in the sun on bare-branched Hawthorns. Yellow-rumped Warblers have the right pancreatic enzymes for digesting the waxy coating on Juniper cones, thus enabling their migration earlier or later than some other birds that need more palatable foods.

Several White-crowned Sparrows and Yellow-rumped Warblers were busily picking cones from Rocky Mountain Junipers and flying in and out of the deciduous trees in the foreground in late September, 2024,

Winter migrators, some Bohemian Waxwings had joined a flock of Cedar Waxwings that live here year ’round on a frosty morning in January. When food sources become scarce in northern climates where the Bohemian Waxwings live in more temperate seasons, they set out in search of food supplies. They were harvesting cones on some Rocky Mountain Junipers (Juniperus scopulorum). This tree is less plentiful in the West Valley than the Common Juniper. As young trees, I often see their blue-ish needles and upright-growing limbs well-browsed by ungulates.

The Red Crossbills above were observed frequently in July, 2020, feeding in these Rocky Mountain Junipers.

European Starlings were feeding on the cones of a Rocky Mountain Juniper tree 10.31.25

Evening Grosbeak male (left) feeding on Rocky Mountain Juniper cones 9.16.26; Evening Grosbeak female stopped for water after feeding on Rocky Mountain Juniper 9.18.26