Canada Thistle

Beware of tall, attractive wildflowers with prickly leaves growing in fields. Most have beautiful magenta or lavender-colored heads, but the leaves, and sometimes the stems, are edged with numerous, sharp spines to defend against herbivores looking for an easy meal. These are the thistles. They are composites, related to daisies and goldenrods in spite of the obvious differences. Most are biennials, starting as a ground-hugging rosette of prickly leaves the first year, then growing tall and flowering the second.
 

The Canada Thistle (Cirsium arvense), a misnamed alien invasive from Europe, is one of the less-obvious species here [in the northern Finger Lakes region of NY] because its light-purple heads are less than an inch high. The whole plant grows four to five-plus feet high and often forms dense colonies after spreading by underground stems. In Europe and northern Asia, it is known as Creeping Thistle. One plant's roots can spread to a three-foot diameter (or more) in one year and continue growing at this rate for many years, making it a difficult plant to eradicate. A single thistle plant can be considered biennial, but the root system is perennial and continues to put its energy into new clonal [cloned] shoots.
 

Canada Thistles form colonies from a spreading underground
 root system. Less energy goes into producing flowers.

Less energy goes into producing flowers which are usually dioecious (either male or female). Male flowers may be slightly smaller, but otherwise similar. Both are very fragrant, which is energy spent to attract pollinators and NOT humans. Female flowers produce 40 to 80 seeds per head, but the fuzzy pappus is loosely attached and often ineffective in seed dispersal.

Canada Thistle's main stems are smooth, but the deeply-lobed leaves are designed to keep you at a distance. In the spring, wear heavy gloves and protective clothing so you can return to the location and collect the young leaves, young stems and roots for food. One of the plant's nicknames is "lettuce from hell" (and it actually is related to lettuce). After removing the spines, add young leaves to salads or eat them cooked. The pithy, young stems are easier to deal with; just peel and eat raw or cooked. The roots of first year plants, before the tall stems begin, are a survival food, but they also can cause flatulence.


A crab spider is camouflaged against a Canada Thistle flower bud.

Canada Thistle is also food for wildlife, especially goldfinches and other finches that eat the seeds. Some butterfly and moth larvae eat the leaves. Look for Red Admirals, Viceroys and Painted Ladies on this thistle. The larvae of the Orellia ruficauda fruit fly parasitize the fertile seed heads, making them a somewhat-effective biological control.

In the past, a tea made from the leaves was used as a general tonic (stimulant) and diuretic to increase the loss of water from the body. Externally, it was used for skin sores and poison-ivy rash. Native Americans used a root tea as a digestive tract stimulant and dewormer. (I wonder what they used before Europeans introduced this wildflower.) At the other extreme, it was said to cause inflammation and irritation (Jacobs and Burlage). Go figure.
 

Cirsium comes from the Greek word, kirsion, from kirsos, a "swollen vein" remedied by one of the species in that genus. The species name, arvense, is Latin for "in the field." Among its other common names are "field thistle," "perennial thistle" and "cursed thistle." It was originally native to the Mediterranean and southeast Europe and likely arrived in North America during the 1600's.

Corrections, comments and questions are always welcome at northeastnaturalist@yahoo.com or connect through my Facebook page and photo page. There's also a community-type page for The Northeast Naturalist. Other nature and geology topics can be found on the parallel blogs Adirondack Naturalist and Heading Out.

Redpolls

It's been a good year for redpolls. Every few years there's an irruption of winter finches from Canada when their food resources are scarce up north.

 

I'm in Upstate New York, and here they hang out with the goldfinches. In fact, they’re related to goldfinches (in the sense that both are in the finch family). They’re about the same shape and size and they eat the same kinds of seeds, but there it ends. Redpolls resemble streaky sparrows with a red cap and black around the bill and the males have an added raspberry wash on the breast. Winter brings them to New York from northern Canada and this is about as far south as they normally need to go. These are tough little birds.

Although they seem perfectly at home in the bushes near our feeders, the redpoll’s natural preference is open fields and patches of weeds. They’re more likely to appear in alternate years or irregularly when seed production from spruce and birch trees across northern Canada and Alaska is reduced. Redpolls also eat the seeds of willows and alders. When they're on the snow under our feeders, they're picking up sunflower seeds dropped by the other birds.

To make it through long, cold nights, redpolls have evolved a version of the crop, a throat pouch (on the esophagus) where a supply of seeds can be stored. After finding a sheltered perch, usually in a conifer, and then fluffing up their dense feathers for added insulation, they slowly digest the stored seeds at their leisure. The combination of food and fluff maintains a core body temperature of 105º F. This allows redpolls to survive colder temperatures than other songbirds.

During the summer they are abundant in boreal forests and open tundra around the subarctic regions of both North America and Eurasia.

Ornithologists, the people who study birds, still can’t decide how many redpoll species exist. At the moment, there are two. The Common Redpoll, Carduelis flammea, is the bird normally seen at winter feeders and traveling in flocks across fields. The rarer Hoary Redpoll, Carduelis hornemanni, is generally lighter in color, giving it a "frosted" appearance, hence the name hoary. Due to individual variations, there is almost an overlap between the two types of redpolls, and some ornithologists believe there is just one species with a number of races. Perhaps DNA studies will help to sort this.

For a small finch that weighs less than an ounce, the redpoll has wonderful adaptations that allow it to survive the toughest winters, not to mention unpredictable summers in its far northern homeland. The next time you’re feeling cold, remember the bird that finds warmth in Upstate New York winters.

For an interactive range map of the Common Redpoll, visit the eBird website and zoom in to your location. Recent report locations (within the past 30 days) are coded red. You also can set a custom date range to find recent reports.

Corrections, questions and suggestions are always welcome at northeastnaturalist@yahoo.com or connect through my Facebook page and photo page. There is a separate community-type page for The Northeast Naturalist. Other nature and geology topics can be found on the parallel blogs Adirondack Naturalist and Heading Out.

Evening Grosbeaks

© Dave Spier

Natural food shortages (of the bird kind) are encouraging Canadian finches to head south for the winter. One of the most colorful is the Evening Grosbeak (Coccothraustes vespertinus), somewhat resembling a giant goldfinch, which is not too far off, since they are related. Goldfinches are five inches long (slightly shorter than a chickadee), whereas these grosbeaks are eight inches.

The male Evening Grosbeak [photo above] is very noticeable with white patches contrasting against otherwise black wings and short, black tail. His body is burnt-gold (yellow) grading to a dark-brown head with yellow forehead and wavy line above the eye. Females [below right] are subdued, with mostly gray on the body and head. The only yellow is confined to her neck. Both sexes have massive, pale-colored bills.

Grosbeaks eat mainly seeds, nuts, berries and buds, and they readily come to feeders (if they're around). We had eight Evening Grosbeaks for several days right after Hurricane Sandy and then they vanished in their nomadic fashion. Three returned briefly and a week later, there were four down the road. Unpredictable is a good way to describe this bird.

As always, you can find photos, range map and voice recordings on the All About Birds website. In addition, find current range information on the eBird Range-and-Point-Maps under Explore Data. Use the search boxes to see a range map for this (or any) species you type and then zoom in to your location. You can narrow the date span with the "Custom Date Range" tool or look for any possible sightings in your area by using the Location tool. Write to me for specific information and links. I also encourage you to submit your own sightings. This is how I keep track of their wanderings in my neighborhood, and the information benefits science.

Corrections, comments and questions are always welcome at northeastnaturalist@yahoo.com or connect on Facebook (Dave Spier, or my photographic naturalist page, plus The Northeast Naturalist).

There's more information from the ABA regarding Evening Grosbeaks and the connection to spruce budworm in their breeding range [mainly the Canadian boreal forest].