Norway spruce – Linda J. Spielman

Perfect Perches

Perches–they’re important to wild creatures for many different reasons. The gray squirrel in the opening image (from yardandgarage.com) is using a perch as a feeding site. The next photo shows a Norway spruce whose dead lower branches provided feeding perches for a red squirrel. You can see how the piles of inedible cone cores and scales accumulated under the branches the squirrel perched on. These accumulations are called middens, and they can build up over time into substantial mounds.

Favorite perches often show signs of usage. The red squirrel that used the perch shown below left a cone scale and a number of opened seeds, some with wings still attached.

Red squirrels may mark perches by biting them. In the next photo you see a Norway spruce branch that bears the distinctive paired incisor marks made by a red squirrel. The lower branches of conifers are usually dead, so these marks don’t heal over and may last quite a while.

In the next photo you see a discovery I made during summer a few years ago. The Norway spruce cone crop that year was early and abundant, and a red squirrel had left a cone core, stripped of its supply of edible seeds, resting on the perch it had used. And in case you’re wondering, no, I didn’t put it there, it was all the squirrel’s doing. The scales that dropped as the squirrel fed can be seen on the ground at the base of the tree.

The photo below shows an unusually well elevated feeding perch used by a gray squirrel.

In the next photo you see what I found on top of the log: the remains of an acorn the squirrel had fed on.

Here’s a perch used not for feeding but for food storage. A gray squirrel lodged a black walnut in the crotch of a honeysuckle branch. I’m not sure what the squirrel’s motivation was–perhaps it was to keep the walnut away from other squirrels.

A perch doesn’t need to be overly high to be suitable. In the next photo you see a log used by a squirrel–it could have been a red or a gray–feeding on a white pine cone.

Rocks can also make good perches. Last August a red squirrel harvested young larch cones and brought them to the rock shown below for consumption. Where rocks or logs are available they are preferred over ground level feeding sites.

But food isn’t the only thing drawing animals to perches. A red fox balanced on the log in the next photo in order to deposit its scat. Scat is important in intraspecies communication, and wild canines prefer to leave their scat in conspicuous positions. Sometimes this requires a little acrobatic ability to position the scat just right.

One of my favorite spring experiences is hearing the drumming of ruffed grouse. Males in search of mates perch on logs or other raised features and beat their wings to produce a resonant booming sound. They prefer platforms that are unobstructed and raised well off the ground. You can see a spot in the center of the image where the bark was dislodged by the drumming bird.

Perches can also be used as observation posts. In the next photo you see a mound of earth thrown up by a falling tree. There were tracks–they were barely visible so I didn’t include a photo–going up the side. The size of the impressions suggested a fox.

On top of the mound (shown in the next photo) there were obvious signs of disturbance, showing that it had been used as a perch. The fox would have sat quietly while it listened, looked, and sniffed for signs of prey animals.

We seem to have circled back around to the topic of food, so here’s my last example of a feeding perch. A black bear climbed the beech tree in the photo below and pulled a nut-bearing branch inwards until it broke off. The bear consumed the goodies, pushed the branch aside and pulled another one inward until it broke. The discarded branches formed a tangled cluster, and the bear might even have stood on the growing mass of harvested branches as it continued to pull more branches in. These branch clusters are known by the somewhat misleading term bear nests, although they have more in common with squirrel middens than with nests. With healthy beeches becoming less abundant, bear nests in beech trees are harder to find than they used to be, but the same kind of sign occurs in apple, black cherry, serviceberry, and oak trees.

Wild creatures know their territories in minute detail, and they’re familiar with all the best perches. The attributes of a perfect perch vary somewhat with the specific animal and situation, but safety and accessibility are always important. The location also needs to be appropriate to the animal’s purpose, whether it’s to consume food, to find food, or to advertise its presence. If we stay alert for perches we can begin to understand what makes a good perch and what they can tell us about the lives of the animals.

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.

Bounty From Above

The season is turning, and red squirrels are obsessed with gathering food stores for the winter. They will rely primarily on the cones of spruce, fir, and pine–and to a lesser extent on larch, eastern hemlock, and white cedar–for survival over the coming months. The squirrels’ preparations for the lean times ahead leave plenty of evidence. In the photo below the ground is littered with red pine cones. A few brown cones that fell the previous year contrast with the green of this year’s crop. When stored in a humid environment the tightly closed green cones will last through the winter without opening, preserving their precious seeds until a red squirrel pulls them apart to get at the nutritious nuggets inside.

The next photo was taken in a stand of Norway spruce, a tree that is native to northern Europe but was widely used in reforestation projects in the US during the twentieth century. Some of the trees in these plantations are large and produce copious crops of cones. The cones’ large size–some as long as eight inches–means they are a bonanza of food for red squirrels.

You can see another harvest in the photo below, this time the cones of white pine. Again, it’s the largest trees, the ones that tower over the rest of the forest, that produce the best crops of cones and attract red squirrels to harvest them.

These arrays of fallen cones don’t usually last long. After working in the tree tops to drop a supply of cones the squirrel descends and transports the bounty to an underground storage space, known as a larder. A red squirrel typically has a number of larders, often made by enlarging the natural spaces that form around large roots. Rock crevices and hollow trees may also be used, and cones are sometimes stored under fallen trees or even in abandoned buildings. Green cones stay tightly closed all winter and well into spring in these humid spaces.

The white pine cones shown in the next image were also nipped by a red squirrel, and these cones probably look more like the ones you’re used to seeing. There must have been an interruption before they could be transported to a storage cavity, because they’ve dried out and released their seeds. Our weather has been dry lately, so drying may have happened unusually quickly, making the cones useless for winter food. So if the seeds were released when the cones opened, where are they, you ask? Such a concentrated serving of edibles wouldn’t have gone unnoticed by birds and small mammals and would have been rapidly consumed.

I was curious about how the squirrels detach cones from branches. I imagined a a lot of yanking and chewing, which should have left tooth or claw indentations somewhere around the sides of the cones. But when I looked for marks, all I could find were small bits of exposed wood at the attachment sites. The photo below shows the lighter separation areas at the bases of some of the red pine cones I examined. On Norway spruce and white pine cones it was the same– all I saw were small separation wounds at the bases.

I realized I needed to see how cones are attached to twigs, and what I found suggests that nipping cones is pretty straightforward. In the next photo you see a red pine cone attached tightly to a twig. A squirrel need only bite through the attachment point by inserting its tiny incisors into the angle between the cone and the twig. This would produce a lighter colored spot at the separation point like the ones I observed on the dropped cones.

I’ve never seen this happening (how I would love to levitate to the top of a tree and watch!) but I did find a video of a red squirrel harvesting cones from a western pine, probably a ponderosa pine. You can see it here. (The clearest view starts at 2 minutes and lasts about a minute.) The squirrel perches on the branch and works from the back side of the cone, occasionally using its front feet but mostly just gnawing at the connection between the cone and the branch until the cone falls.

Finding the evidence left by these frenetic little creatures isn’t hard–just pay attention to what’s on the ground whenever you pass under conifers. You’re most likely to find signs of harvesting where there are middens (piles of discarded cone scales and cores) from previous years, since resident squirrels tend to keep the same territories year after year. And sound may guide you to a harvesting site. A falling cone lands with a thump; the bigger the cone the louder the thump. If a falling cone hits branches on the way down you’ll hear some plunks and bonks followed by a thump. Follow your ears toward the sounds and you’ll probably find nipped cones scattered on the ground and a red squirrel chattering angrily at you from high in the tree.