Red Squirrels and Norway Spruce: A Special Relationship

The staccato warning call of a red squirrel is a common sound in our northeastern forests. These feisty animals are extremely protective of their territories, and they seem to react to the presence of people as much as to other squirrels. Red squirrels are found in both hardwood and coniferous woodlands, but their numbers are highest where there are extensive stands of conifers. In the Northeast one of their favorites is the Norway spruce (Picea abies). These majestic trees are native to northern Europe, but were planted extensively during the 19th and 20th centuries. Their tolerance of poor soils made them ideal for degraded sites, and many stands were established on abandoned farm land during the Depression.

Open grown Norway spruce trees are impressive for their height and form. The specimen shown above exhibits the large cones (up to 6 inches long) and the drooping branchlets that help to differentiate Norway spruce from other spruce species. In plantations the huge cones littering the ground reveal the tree’s identity, and even fairly young trees show drooping branchlets like those in the next photo.

Red squirrels feed on the cones of many different conifers, but they find the large fruits of the Norway spruce especially attractive. Cones are stored in underground larders and supply the animals with sustenance over the winter and often well into spring. Red squirrels like to feed on perches, and in winter they favor low branches located above or near their larders. Years of use can result in impressive middens of discarded cone scales and cores like the one below.

Conifer cones reach maturity in late summer, and the period between the exhaustion of the previous year’s provisions and the ripening of the new crop can be a lean time. Tree buds, berries, underground tubers, and insects help to carry red squirrels over this stretch, but conifer cones are their go-to choice. For most conifers species the cones don’t provide much nutrition until they have reached nearly full size, but Norway spruce is different. Because of their size, even immature cones attract hungry red squirrels. I’ve found evidence of red squirrels extracting tiny seed meats from the current year’s cones as early as late June. At this stage logs and stumps are often used as feeding perches. The red squirrel that left the remains in the next photo found a perfect picnic table.

In the close-up below you see the partly processed cone and some of the cone scales and seed remnants. Squirrels work on cones starting at the base, tearing off each scale and biting a hole in each seed coat to extract the nutritious contents.

Sometimes the accumulations of cast-off cone scales and seed remnants can be quite colorful. In the photo below there’s a pile of cone scales in the upper left and a scattering of winged seeds in the center. At the very top of the frame you see the outer aspect of several scales. Their exposed tips are bright green and the parts that were overlapped by the scales below are tan or reddish. Below and to the left of those, there are several scales with their inner sides showing. The green ovals outlined with red show where the seed wings were positioned. In the center of the photo you see what remains of the seeds, tan seed coats attached to the maroon seed wings. Ragged openings in the seed coats show where the meat was extracted.

The next two photos show the inner aspect of a single cone scale. In the first shot there’s one winged seed on the left, still lodged where it formed. The squirrel extracted the meat by biting into the base of the seed without displacing it. For the next shot I removed the seed so you can see how it rested against the inside of the scale.

As red squirrels begin to feed more and more on the current season’s cone crop, brightly colored discards pile up on the brown remains from previous years.

In a month or so red squirrels will begin the serious business of putting up stores of cones for the coming winter (see my post, Bounty From Above, September 14, 2020). If you do some investigating when you come across stands of Norway spruce you’ll get a look into the lives of red squirrels and the seasonal cycles which have shaped their behaviors.