Thursday, August 15, 2019

What is a thistle sock? What is a thistle feeder?

You may have heard the term "thistle feeder" or "thistle sock" in regards to bird feeding but perhaps don't know exactly what that is. So, first, here is the definition.

A thistle feeder is a specially designed birdfeeder that dispenses the seeds of the niger (also trademarked as "Nyjer") flower Guizotia abyssinica. A thistle sock is a type of thistle feeder made with an open weave fabric mesh that resembles a sock.

Continue reading to learn more about thistle feeders. Thistle feeders can really attract the most colorful birds to your bird feeding station and backyard. I'll tell you how to set them up and maintain them in order to get the most out of your thistle feeder and keep birds coming back.


In this article
What is a thistle feeder?
What kind of seeds go into a thistle sock or feeder?
What kind of birds are attracted to thistle feeders?
How to hang a thistle sock
Cleaning your thistle feeder


What is a thistle feeder?

Also called a finch feeder, thistle feeders can take a couple of forms. They can be a clear plastic tube feeder with very small dispensing holes. They can be metal bird feeders with a small mesh screen. And they can be fabric thistle socks. In each case, a seed is pulled out of the feeder by the bird, it is not supposed to fall out on its own. The seed is not provided loose, as on a tray.

Photo of American Goldfinch on tube thistle feeder
American Goldfinch on tube thistle feeder
Image by aekadtke from Pixabay
Clear plastic tube feeders for thistle are similar to other tube-style seed feeders. However this type of thistle feeder uses very small dispensing holes so that the thistle (niger seed) does not fall out easily. Instead, the small finches that eat this birdseed pull the seed out of each dispensing hole.

There are three main styles of tube thistle feeders. The typical kind is shown above. It has 6 feeding ports, each with a perch below. Larger sizes with more feeding ports are available. Typical lengths are 17 inches and 36 inches tall.

A variation on this is a feeder that has a perch that spirals around the tube several times. It doesn't necessarily have more feeding ports. Rather, the continuous spiral perch allows more birds on the feeder to take their turn and not fly off. It seems like a really clever idea.

Speaking of unique, one manufacturer has an "upside down" thistle feeder. The feeding ports are below the perches. Finches hang upside down to reach the food! Finches don't mind doing this, as they naturally feed on the tips of flower heads and trees to reach seed. But this kind of setup may keep undesirable larger birds from raiding the seed.

Photo of Lesser Goldfinches on thistle feeder
Lesser Goldfinches on metal mesh thistle feeder
Photo by Greg Gillson
Metal mesh thistle feeders allow birds to perch anywhere on the side of the feeder. The screen-like mesh allows seeds to be extracted from anywhere on the feeder, unlike the plastic tube feeders from which seed is only dispensed from a very few ports.

These are sturdy feeders and will likely last many years. Some have broader covers over the top to keep out the rain. Some have wider trays at the bottom that may catch seeds that fall out.

Some thistle feeders have internal baffles that help distribute the seed better throughout the feeder. Without such a baffle, when the seed is low, it is all at the bottom of the feeder where only a few birds can feed at a time. With baffles, even if the seed is low, it is still distributed to several levels of the feeder. This allows more birds to feed at once until it runs out of seed.

Photo of an American Goldfinch eating from a thistle sock feeder
American Goldfinch on a thistle sock
Image by Paul Brennan from Pixabay
Thistle socks are fabric mesh feeders through which the pointed thistle seeds protrude. Finches land on the mesh and pull out the seeds.

This is what usually comes to my mind when someone says thistle feeder. Thistle socks do, indeed, look like a white tube sock. Some are small, only a foot long or so. Others can be 30 inches long. They have a drawstring at the top to refill when empty.

Because they are fabric they aren't very expensive, which is good. On the other hand, they may mold or deteriorate more quickly in wet winter weather. They can snag or develop holes that waste seed onto the ground. So they don't last as long as the metal mesh feeder, for example.

What kind of seeds go into a thistle sock or feeder?

Thistle feeders are designed to feed wild birds with the seeds of the niger plant Guizotia abyssinica. The niger plant is an erect annual herb with a yellow flower in the aster, daisy, sunflower family.

Niger is native to Ethiopia and Malawi. It is also grown in India. The seeds from the plant yield cooking oil that is a substitute for olive oil. The seeds are also used as food in India and for medicinal purposes in Ethiopia (source).

Niger seed is grown for birdseed and sold world wide. Despite frequently being called thistle seed, niger is not a thistle. Early on it was marketed as "thistle" seed as the finches who eat niger seed are well-known for eating thistle seeds. The thistle name stuck for the feeder. Nyjer is trademarked by the Wild Bird Feeding Industry association. So that is the name you will often see when buying packaged birdseed.

The actual seeds are similar to sunflower seeds, though black, smaller, and much thinner. Despite their small size, they still have two inedible hulls on each side of the edible kernel. Seeds are sterilized with high heat to prevent it from growing and becoming an invasive plant.

Photo of a Pine Siskin and Lesser Goldfinch on a thistle feeder
Pine Siskin (left) and Lesser Goldfinch (right) on thistle feeder
Photo by Greg Gillson

What kind of birds are attracted to thistle feeders?

Thistle feeders are designed to dispense very small seeds to attract the tiniest of the finches. Finches feed primarily on seeds. Some finches eat larger pine cone seeds. Some finches eat tiny dandelion seeds. Each type of finch has a preferred food.

In North America, the finches that are most attracted to thistle feeders include American Goldfinches, Lesser Goldfinches, Pine Siskins, House Finches and Common Redpolls.

Photo of a male American Goldfinch on teasel
American Goldfinch
Photo by Greg Gillson
American Goldfinches are found to Canada in summer, to the Mexican border in winter, and across most of the mid-latitudes of the United States year round. Thus, these bright birds are likely to visit your thistle feeders at some time of year no matter where you live in the lower 48 States and southern Canada. Strikingly yellow, black and white in summer. In winter they molt into a much muted cream and brown plumage. Females lack black crown and are duller in both summer and winter.

Photo of Lesser Goldfinch in willows
Lesser Goldfinch
Photo by Greg Gillson
Lesser Goldfinches are found in the West and southwestern United States and southward into Middle America. Greenish above, yellow below--including under the tail--they remain in this same plumage all year, unlike the American Goldfinch which becomes quite dull in winter. Females lack the black crown.

Photo of a Pine Siskin at a feeder
Pine Siskin
Photo by Greg Gillson
Pine Siskins breed across Canada and extreme northern states of the US. Also from Alaska to Mexico in the mountains. In winter they descend to the lowlands and visit thistle feeders. Irregularly, they irrupt and become common in winter in large flocks throughout the lower 48 States. They are goldfinch-sized brown-streaked birds with yellow highlights in wing and tail.

Photo of a House Finch in a tree top
House Finch
Photo by Greg Gillson
House Finches are commonly found in cities and backyards across the United States and Mexico. They are a bit larger than the other birds pictured here (6 inches long bill tip to tail tip, rather than 5 inches as the goldfinches). They have a larger bill and usually eat seeds larger than the niger seed. Nevertheless, they'll eat the thistle seed occasionally. They are brown streaked birds of the trees (sparrows usually hop on the ground). Males have red crown, chest, and rump.

Photo of a Common Redpoll in an alder tree
Common Redpoll
Photo by Greg Gillson
Common Repolls live in subarctic forests and tundra. In winter they move south through Canada, rarely to the northern tier of states across the US. So, this is an unlikely visitor to your thistle feeder unless your winters are typically very cold and snowy. Their plumage is very pale, almost white, thinly streaked with brown, with males sporting a red cap and black chin.

Other: Other birds may eat niger seed from thistle feeders occasionally. Birds noted to try it include Dark-eyed Juncos, Indigo Buntings, Purple Finches, Song Sparrows, some quails, doves and chickadees, too.

How to hang a thistle sock

Hanging a thistle feeder is not difficult. The tube type or metal mesh type thistle feeders have metal handles just like any other birdfeeder. They can go on poles or posts. They can hang from tree limbs. Marlene and I prefer shepherd's hooks.

Thistle socks are generally just tied onto a horizontal limb or hook with the draw strings that make up the top of the sock. Then they hang freely. They wear out in the weather, so replace them if they get a hole or are soiled. Some types have a plastic top similar to other tube type bird feeders.

When you are thinking about thistle feeder placement there are a couple of things to keep in mind. Finches generally prefer trees to flee to. So placing the thistle feeder in or near a tree may make it more favored. On the other hand, you don't want it too near the ground or near low bushes where a cat could hide and pounce. Some people advise placing thistle feeders away from other feeders. I've seen thistle socks high, low, in the open and nearly hidden in the bushes. They one thing they had in common? The birds loved them no matter what.

There is one thing about niger thistle seed, though. If it dries out it loses its oily goodness and the birds will not eat them. Don't buy too much seed at a time. Keep it fresh. Squeeze the seeds with your finger nails to see if they are oily. If not, replace the seed with fresh.

Cleaning your thistle feeder

Plastic tube feeders and metal mesh thistle feeders may hold moisture. Seeds gum up in the bottom and begin to mold. If this happens, immediately throw out the bad seed and wash thoroughly with 10% bleach solution and scrub out.

Thistle socks may air dry after a rain. But mold will form if you live in a damp climate. If thistle socks become moldy throw them away. They are relatively inexpensive and are often sold as a pair. Only hang one at a time, so you have a replacement if the first one gets moldy or develops a hole.

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