The remnants of frozen highbush cranberries show the work of seed-extracting pine grosbeaks. (Courtesy Photo | Kathy Hocker)

The remnants of frozen highbush cranberries show the work of seed-extracting pine grosbeaks. (Courtesy Photo | Kathy Hocker)

Seeing Red: Highbush cranberries in the snow

Post-holing pays off as naturalists find berries, birds and squirrels

A hard crust on top of deep snow made it exhausting to go off-trail very far. Even with snowshoes, the post-holing was hard going. So our forays weren’t very long. Nevertheless, the curious naturalists found several things of interest.

There was still some open water in the sloughs, so crossing them was dicey, and we diverted to the Moraine Ecology Trail, which was partially packed down by previous walkers. Here, we noticed new spiderwebs laced across recent footprints and other divots. Even though we did not see the owners of the webs, it was clear that they can be active in cold weather. In addition to these web-builders, we sometimes see jumping spiders huddled on top of snow. Spiders are out and about, but what can they hope to capture and eat?

[Tracking animal footprints in the snow]

The next day, after much dithering about where to walk, we ended up on the first part of the well-packed trail along Eagle River. This turned out to be quite productive for us.

The first thing that captured our fancy was a snowy, suspended log that supported a few blueberry bushes and at least four stands of the now-dead-and-brown flowering shoots of northern ground cone. This plant has no green leaves, so it cannot photosynthesize carbohydrates for itself. It is totally parasitic, mostly on alder, but occasionally on other species, perhaps blueberry in this case.

[The Mating Game]

Presently, we began to see red — fragments of highbush cranberries in numerous, widespread patches on top of snow-covered logs and hummocks. There were a few whole berries, but in nearly all cases the seeds had been extracted, leaving bits of red pulp and fruit skins. Aha! Pine grosbeaks had been at work! Part of their scientific name reflects this behavior: “enucleator” meaning seed (or nut) extractor, although they also eat many other kinds of seeds, buds and insects. They typically nest in open conifer forests of boreal North America and Eurasia; here, in fall and winter, at least, they regularly enucleate highbush cranberries.

We conjectured that the birds found it hard to handle the frozen fruits while perched in the shrubs (in warmer weather, they commonly process the fruit while perched) and brought them down to the snow. There they may have been able to brace each berry on the hard surface while biting it, or maybe they could use the snow as an anvil for striking it. Since the berries grown in clusters, by yanking on one, the birds may have incidentally brought down a few more, some of which were not opened (but why not?).

[Wild Shots: Photos of Mother Nature in Alaska]

A bit later, we came upon an active red squirrel residence, with three entrances less than a meter a part. Outside of one doorway was a scattering of black, dried-up devil’s club berries, mostly with the seeds removed. There were also two very bedraggled spruce cones that looked like they’d spent too long in the underground cache. On both old cones, the squirrel had removed only the basal two rows of cone scales. Spruce cones usually bear seeds on the scales of the lower half (or so) of the cone and not at the tip, but these cones apparently did not have a full complement of good seeds.

On our way out, my companion heard a woodpecker, so of course we stopped to look. About 30 feet up a narrow spruce tree, the bird was at work, tapping the trunk and flaking off bark scales. It was hard to get a good look at it — woodpeckers often seem to go to the back side of a tree, keeping the trunk between them and us. But eventually, this bird came around far enough that we could see its all-black back, no white showing at all. Oh good! A black-backed woodpecker, which is quite a rare species in our area (and I got lucky a few years ago in Gustavus, which I found a nest of this species just at the time that the chicks were fledging).

This woodpecker forages mostly on dead and dying trees in coniferous forest, often after a forest fire. They eat a lot of wood-boring beetles, extracted by hammering holes in the wood. They have stronger hammering power than most other woodpeckers. They stand farther from the tree trunk and use the whole body to pound a hole. Unlike most other woodpeckers, they have only three toes on each foot — there is no hind toe. Ornithologists speculate that somehow the lack of the hind toes facilitates the heavy-duty pounding.

• Mary F. Willson is a retired professor of ecology. “On The Trails” is a weekly column that appears every Friday. Her essays can be found online at

More in News

Michael Penn / Juneau Empire File
The Aurora Borealis glows over the Mendenhall Glacier in 2014.
Aurora Forecast

Forecasts from the University of Alaska Fairbanks’ Geophysical Institute for the week of March. 19

(Michael Penn / Juneau Empire File)
Police calls for Tuesday, March 21, 2023

This report contains information from law enforcement and public safety agencies.

This September 2015, photo provided by NOAA Fisheries shows an aerial view of adult female Southern Resident killer whale (J16) swimming with her calf (J50). New research suggests that inbreeding may be a key reason that the Pacific Northwest’s endangered population of killer whales has failed to recover despite decades of conservation efforts. The so-called “southern resident” population of orcas stands at 73 whales. That’s just two more than in 1971, after scores of the whales were captured for display in marine theme parks around the world. (NOAA Fisheries / Vancouver Aquarium)
The big problem for endangered orcas? Inbreeding

Southern resident killer whales haven’t regularly interbred with other populations in 30 generations.

Juneau Brass Quintet co-founding member Bill Paulick along with Stephen Young performs “Shepherd’s Hey” to a packed house at the Alaska State Museum on Saturday as part of the quintet’s season-ending performance. Friends of the Alaska State Library, Archives and Museum sponsored the event with proceeds going to the musicians and FoSLAM. (Jonson Kuhn / Juneau Empire)
Top brass turns out for event at State Museum

Free performance puts a capt on a busy season.

Alaska’s state legislators are slated to get the equivalent of 6,720 additional $5 bills in their salary next year via a $33,600 raise to a total of $84,000 due to a veto Monday by Gov. Mike Dunleavy of bill rejecting raises for legislative and executive branch employees. (AP Photo/Ted Shaffrey, File)
Veto negates rejection of pay hikes for governor, legislators

Dunleavy clears way for 67% hike in legislative pay, 20% in his to take effect in coming months

On Thursday, the Alaska State Board of Education approved a resolution that supports barring transgender female students from participating in girls’ sports. (Getty Images illustration via Alaska Beacon)
State school board supports barring transgender female students from participating in girls’ sports

On Thursday, the Alaska State Board of Education approved a resolution that… Continue reading

Mark Sabbatini / Juneau Empire 
State Sen. Lyman Hoffman, D-Bethel, asks Randy Bates, director of the Division of Water for the Alaska Department of Environmental Conservation, about state water quality regulations some fish hatcheries are calling harmful during a Senate Finance Committee meeting Friday. The meeting was to review the DEC’s proposal to take over responsibility for many federal Clean Water Act permits, claiming it will be more responsible and efficient for development projects. Some of the senators questioned both the cost of the state taking over a process currently funded by the federal government, as well as the state’s ability to properly due to the job within the guidelines for such a takeover.
Wading into rule change proposals affecting clean water

National PFAS limits, state takeover of wetlands permits raise doubts about who should take charge

Guy Archibald collects clam shell specimens on Admiralty Island. Archibald was the lead author of a recently released study that linked a dramatic increase of lead levels in Hawk Inlet’s marine ecosystem and land surrounding it on Admiralty Island to tailings released from the nearby Hecla Greens Creek Mine. (Courtesy Photo / John Neary)
New study links mine to elevated lead levels in Hawk Inlet

Hecla Greens Creek Mine official ardently refutes the report’s findings.

(Michael Penn / Juneau Empire File)
Police calls for Saturday, March 18, 2023

This report contains information from law enforcement and public safety agencies.

Most Read