Dave Hallock, Eldora. Pine cones have been abundant on the ground this year. If you walk on trails and the sides of roads, you know this. Within the past 12 months most of our conifers have had a better than average cone crop - ponderosa pine, Douglas-fir, Engelmann spruce, subalpine fir, limber pine, and lodgepole pine have all been cone laden. The timing of poor to abundant cone crops seems to be synchronized for each species - Douglas-fir and subalpine fir have a good cone crop at least every 10 years, ponderosa pine and Engelmann spruce a more frequent 3-5 years, and lodgepole pine at least every 3 years. But it is not often when all the tree species have a better than average cone crop within a year of each other. The current abundance of cones began last fall and has continued through this summer. 

When the trees are producing lots of cones, the cones themselves generally have more seeds. That means lots of food for animals. While many different animals can have cone seeds as part of their diet, some are more dependent on them as a food source and have even developed specialized “tools” for a more efficient harvest. 

Red Crossbills are birds that are some of the most specialized for extracting seeds from conifer cones. As their name implies, the ends of their bills are crossed sideways - one goes one way and the other does the opposite. It is a great tool for opening up pine cones and then inserting their tongue to extract the seed. As they are dependent on seeds for food, they go where the food is best - they are nomadic looking for areas having a bumper cone crop. They nest when they find abundant food - there are nesting records for them in every month of the year. Since last fall Red Crossbills have had very high numbers on the local Indian Peaks Bird Counts. It is suspected that they nested locally this winter as immature birds were observed in the spring. They are generally found in flocks and seen in the tops of cone-laden trees (finch size, males with red bodies and dark wings) or heard flying overhead (kip kip kip). There are nine “types” of Red Crossbills (possibly different species) and each specialize on a different conifer - we mostly have “Type 2” which favor ponderosa pine and “Type 5” that favor Engelmann spruce, along with “Type 4” who favor Douglas-fir. The crossbills favoring ponderosa pine (Type 2) have a slightly larger bill and the pine’s seeds are the largest - evolution in action.

The less common White-winged Crossbill is another nomadic bird that follows the cone crop. Their numbers are generally low throughout Colorado, as this is about as far south as they go, primarily being a boreal species most common from Alaska to Newfoundland. As their name implies they have a crossed mandible along with white wingbars, otherwise look like a Red Crossbill. We rarely find them on the Indian Peaks Bird Count, but they have been detected on the last three counts (fall, winter and breeding). They were documented as nesting in western Boulder County several decades ago in the subalpine forest above Brainard Lake in mid-winter.

Clark’s Nutcrackers are also heavily dependent on cone seeds, particularly from the pine family. They are slightly larger than a Steller’s Jay, with a smoky gray head, neck, and body, black with white-tipped wings, and black-centered tail with white edges. Their bills are large and pointed - they can easily drill into green pine cones to extract the seed. Generally flying in flocks, they are often heard before seen, making grating calls of kraaa, kraaa. Locally they especially like limber pine, but will use different tree species in other parts of Colorado. And they cache nuts for the following spring. A few years ago while working between Salida and Buena Vista in piñon pine habitat I had an interesting experience with nutcrackers. At one location in late May, approximately 50 of them were present, often on the ground excavating piñon nuts, and some of the birds were being fed by others. During two subsequent visits to the same spot in June, from 30 to 50 nutcrackers were still present - excavating pine seeds from the ground and adults feeding young.

Other bird species that include conifer seeds in their diet and may numerically increase with a good cone crop are Mountain Chickadee, all three nuthatch species, Pine Siskin, Pine Grosbeak, and Cassin’s Finch.

The mammalian king of the cone crop is the Chickory (also called Pine Squirrel). Chickarees have a very interesting method of food storage. Large piles of debris, containing those parts of the conifer cones not eaten, will develop around the bottoms of favored feeding trees. The debris piles are called middens, which are used to cache green conifer cones before they ripen and release their seeds. Sites that have been used for several generations of squirrels can have middens several feet deep and 25 feet across. Lodgepole pine forests are particularly important to Chickarees. They have the most consistent and persistent cone crop of the local conifers. Generally, only fire or the gnawing of a rodent will release the seed. One of the classic sounds of fall is the dropping of pine cones to the ground, or on your roof. Chickarees can cut a cone every couple of seconds and may cache several thousand cones each year. 

Other mammals that may favor eating conifer seeds when abundant are Golden-mantled Ground Squirrel, Red-backed Voles, and chipmunks.

The Indian Peaks Bird Count is heading into its 40th year. This summer we observed more birds than last year but still below normal. Yes, there were a lot of Broad-tailed Hummingbirds around this summer. Over the 39-years of the count, there is an indication that they have been increasing; we observed about 250 per 100 hours of the count during the first 20 years and about 350 for the past 19 years. Participants who helped with the count this year were Linda Andes-Georges, Bev Baker, Suzanne Bhatt, Maureen Blackford, Alex Brown, Diane Brown, Gillian Brown, Jack Bushong, Ryan Bushong, George Coffee, Todd Deininger, Andy Dorsey, David Dowell, Virginia Evans, Mike Figgs, Fern Ford, Audrey Godell, Dave Hallock, Paula Hansley, Dave Hill, Elaine Hill, Jim Holitza, Steve Jones, Nan Lederer,  Greg Massey, Eliza Maxfield, Eric Maxfield, Holden Maxfield, Mary Maxfield, Lisa McCoy, Loren Merrill  Merle Miller, Sally Miller, Naseem Munshi, Carol Newman-Holitza, Mark Pscheid, Jeannie Reynolds, David Schiff, Cara Stiles, Lucy Stroock, Mike Tupper, Susan Wagner, Marty Wolf, and Patty Zishka.

Following are some of the September nature happenings in the Nederland area. I call this the time of “dropping cones and shedding needles.” Squirrels are dropping pine cones to the ground for winter reserves to be stashed in their middens. Needles on many conifers will start turning brown, particularly on lower branches and the inner portions of other branches, as the trees shed excess foliage. Of course, if you see all the needles turning brown, you may have a larger problem.  

Berries continue to ripen. Look for huckleberries, chokecherries, raspberries, and others. If you hit a good patch of huckleberries, you can smell their wonderful aroma in the air. Black bear diets heavily shift toward berries as they gorge themselves for winter hibernation; this is evident in their scat.

Bull elk are bugling. The peak of the rut occurs around the end of September. Moose also start having other things on their mind, as breeding begins around mid-September and runs until early November.

Pocket gophers will continue to aerate the ground by tunneling and leaving mounds of dirt on the surface.

Birds are on the move. Flocks of sparrows, warblers and bluebirds are coming from the north, while local birds are flocking up and getting ready to head south. The tundra is a good place to see migrating birds that are feeding on abundant grasshopper and cricket populations. Raptors, including Red-tailed Hawks, Golden Eagles, Northern Harriers, American Kestrels, Peregrine Falcons, and Prairie Falcons, frequent the tundra during fall migration.

A few butterflies will still be around in September. Some of these, like Commas (orange with black spots and angular wings) and Mourning Cloaks (large, dark brown with yellow stripes), will overwinter as adults and can emerge during warm periods in winter or in early spring. While not much is known about Painted Ladies migrating south, some are often seen in September and October in high elevation meadows making a strong southwest movement. 

Moose photo by Kirk C. Watkins.

(Originally published in the September 3, 2020, edition of The Mountain-Ear.)