A Thistle Banquet

On a recent walk through a local meadow I spotted a bank of Field Thistle (Cirsium discolor).

Field Thistle (Cirsium discolor)

It was eye-catching for two reasons.  The sight of the plant itself is arresting, with its tall candelabra-like shape topped with purple pompoms of flowers instead of candle flames.  But it was the sight of so many visitors to the flowers, often several on a single flower head, that was really breath-taking.  Bumble Bees, Honey Bees, Clearwing Moths and so many different butterflies moved quickly from flower to flower, pausing briefly to dine.  Field Thistle presents a sumptuous feast for potential pollinators!

At one ‘banquet table’, a Honey Bee, a Thistle Long-horned Bee (Melissodes desponsus) and a Hummingbird Clearwing Moth all dined amiably together.

A Honey Bee, a Thistle Long-horned Bee (Melissodes desponsus) and a Hummingbird Clearwing Moth all drinking nectar from Field Thistle (Cirsium discolor)

At another, several Bumble Bees, Honey Bees and Thistle Long-horned Bees shared a meal.

Bumble Bees, Honey Bees and a Thistle Long-horned Bee (Melissodes desponsus) feeding from Field Thistle (Cirsium discolor)

How is it that one flower head can accommodate so many visitors simultaneously?  Field Thistle is a member of the Aster or Composite (Asteraceae) family.  Each of the purple pompoms consists of a cluster of many long narrow tubular disk flowers.  You can see the individual flowers in the head in the lower part of the photo below.

Field Thistle (Cirsium discolor). Note the individual narrow, trumpet-like disk flowers shown below the bee.

The Long-horned Thistle Bee in the photo below is actively eating both pollen and nectar, and harvesting more to provision her nest for her larvae.  You can see the pollen she has collected packed onto hairs, called scopae, on her hind legs. We know this is a female, because only female bees harvest food for their offspring.  This bee species specializes on pollen from Field Thistle and a few other closely related plants (all of the genus Cirsium) for her larvae.  This makes her an excellent pollinator for Field Thistle, since she won’t be visiting other flowers.  It also means that without these thistles, this bee species would not survive.  It’s the same concept as the Monarch butterfly’s dependency on Milkweeds (Asclepias species) for survival, because Milkweeds are the only food their caterpillars can eat.

Thistle Long-horned Bee (Melissodes desponsus) feeding on Field Thistle (Cirsium discolor). She’ll bring the pollen on her hind legs to her nest. Note the pollen grains all over her body! Some will help with pollination.

Although it appears in the photos above that the various visitors to these flowers are happy to share the wealth of the Field Thistle banquet, I’m sorry to have to report that the Honey Bees actually indulged in bullying behavior.  They were especially hostile to the Thistle Long-horned Bees, trying to chase them away by bumping them.

Honey Bee bullying Thistle Long-horned Bee (Melissodes desponsus) on Field Thistle (Cirsium discolor).

Fortunately, the Thistle Long-horned Bees were undeterred.  They were also respectful of other diners, even those smaller than themselves.

The small bee (possible Eucera species) in the upper left is harvesting pollen. With Thistle Long-horned Bee (Melissodes desponsus) on Field Thistle (Cirsium discolor).

I visited this meadow several times within a few weeks, and each time there were at least a half dozen Hummingbird Clearwing Moths at the thistle.

Hummingbird Clearwing Moths on Field Thistle (Cirsium discolor).

Their close relative, a Snowberry Clearwing Moth, also stopped by for a drink.

Snowberry Clearwing Moth drinking nectar from Field Thistle (Cirsium discolor).

One of the Hummingbird Clearwing Moths shared a thistle banquet table with a female Zabulon Skipper, while a male Zabulon Skipper and Peck’s Skipper dined together at another.

Female Zabulon Skipper and Hummingbird Clearwing Moth drinking nectar from Field Thistle (Cirsium discolor).

Male Zabulon Skipper (left) and Peck’s Skipper drinking nectar from Field Thistle (Cirsium discolor).

These skippers are small butterflies who specialize on various grass species as food for their caterpillars.  Many of these grasses can be found nearby in the meadow.

Peck’s Skipper drinking nectar from Field Thistle (Cirsium discolor).

Peck’s Skippers were ubiquitous, sipping nectar alone and in the company of others, including Spicebush Swallowtails and Great-spangled Fritillaries.

Spicebush Swallowtail and Peck’s Skipper drinking nectar from Field Thistle (Cirsium discolor).

Two courting Great-spangled Fritillaries and Peck’s Skipper on Field Thistle (Cirsium discolor).

Eastern Tiger Swallowtails also visited the flowers for nectar.

Eastern Tiger Swallowtail drinking nectar from Field Thistle (Cirsium discolor).

All of these large butterflies specialize on plants found in the adjacent woodlands as food for their caterpillars.  Spicebush Swallowtails require Spicebush (Lindera benzoin), their namesake plant, or Sassafras (Sassafras albidum);  Great-spangled Fritillaries need violets; and Eastern Tiger Swallowtails use various tree species, including Ash (Fraxinus species), Tuliptrees (Liriodendrun tulipifera), and Black Cherry (Prunus serotina).

It was very encouraging to see that there were many Monarch butterflies partaking of the thistle feast.  Both Common (Asclepias syriaca) and Swamp Milkweed (Asclepias incarnata) were available in the meadow for egg-laying.

Monarch butterfly drinking nectar from Field Thistle (Cirsium discolor).

Even Ruby-throated Hummingbirds visited the thistles for nectar, but they didn’t stay long enough for a photo op.

Field Thistle’s strategy to protect itself from being eaten is to have very spiny leaves and branches.  This works well in deterring mammals from munching the plant; Field Thistle is not a species that deer are likely to browse.  But caterpillars are a different story.  Painted Lady butterflies as well as Common Loopers and some other moth species use this plant as food for their caterpillars.

Painted Lady on White Snakeroot (Ageratina altissima). Field Thistle (Cirsium discolor) is one of the plant species that Painted Lady butterflies can use as food for their caterpillars.

Common Looper Moth on New England Aster ( Symphyotrichum novae-angliae). Common Looper Moths caterpillars also eat the leaves of Field thistle (Cirsium discolor).

After all of this help with pollination, Field Thistle produces seed-like fruits called achenes.  They have a light, white fluff (called pappus) attached, enabling their dispersal by the wind. But these fruits are also desirable food and nesting material for Goldfinches and other birds.

Eastern Goldflinches harvesting seeds from Field thistle (Cirsium discolor)

Field Thistle is native from Saskatchewan to Quebec provinces in Canada and in much of the eastern half of the United States, although it is less common in the southeastern states and absent from Florida.  The flower color can vary from purple to pinkish, and is occasionally white.  Field Thistle is a biennial or short-lived perennial, replacing itself by producing seeds.  It can grow to a height of five to seven feet (1.5 – 2.1 meters).  Unlike some non-native thistles, Field Thistle is not invasive.

There is a non-native thistle, Bull Thistle (Cirsium vulgare), that closely resembles the native Field Thistle.  Some differences in their characteristics that can help tell them apart include:  Field Thistle leaves have consistently white felt-like or woolly undersides, Bull Thistle leaves are green to greenish-white below;  Bull Thistle has winged stems where the leaves meet them, Field Thistle does not;  Field Thistle usually has a ring of leaves pointing upward hugging the base of the inflorescence (flower head), like a very pointy stand-up collar, Bull Thistle may have one or two leaves below the inflorescence.

Field Thistle (Cirsium discolor) with great-spangled Fritillary butterfly. Note the stand-up leaf collar hugging the base of the flower head.

Field Thistle isn’t traditionally used in gardens, but in the right location in a sunny garden, it could really make a statement, and bring so many visitors!

Field Thistle (Cirsium discolor)

 

Related Posts

A Butterfly garden that Embraces the Shade

Asters Yield a Treasure Trove

Black Cherry – for Wildlife and People, Too!

For Great-spangled Fritillaries, Leave the Leaf Litter

Spicebush or Forsythia?

Resources

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Clemants, Steven; Gracie, Carol. Wildflowers in the Field and Forest. 2006.

Newcomb, Lawrence.  Newcomb’s Wildflower Guide.  1977.

Peterson, Roger Tory; McKenny, Margaret.  A Field Guide to Wildflowers of Northeastern and Northcentral North America. 1968.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Illinois Wildflowers

Invasive Plant Atlas of the United States: Bull Thistle

USDA NRCS Plant Database

USDA NRCS Plant Fact Sheet

 

 

 

Encounter with a Bluebird Family

As I approached a place where a meadow meets a narrow strip of woods, I noticed some movement in the shadows cast by a Tuliptree (Liriodendron tulipifera).  The light was low, so I had to use binoculars to be able to see that the bird flying from the ground to a low branch was an immature Eastern Bluebird.

Immature Eastern Bluebird

This is just the kind of habitat Eastern Bluebirds prefer, open meadows or even lawns with trees nearby for perching and nesting.  Bluebirds nest in cavities, using natural cavities and abandoned woodpecker holes in trees. This kind of real estate is in high demand, so Bluebirds also use nesting boxes.  The male brings materials to the nesting site, including grasses, spent plant stems and pine needles for the outside of the nest, finer grasses and sometimes animal hair for the inside.  The female is in charge of construction, building the nest inside their chosen cavity.

This youngster was apparently already learning and practicing a common Bluebird food foraging behavior, that of sitting on a low branch and flying down to capture an insect meal.  As is the case with most birds, insects and spiders are an important part of a Bluebird’s diet. Bluebirds eat quite a variety, including beetles, grasshoppers, crickets, and caterpillars.

Grasshopper – A good meal for a hungry Bluebird!

Tulip Tree Beauty – Nothing beats a caterpillar as a tasty treat!

In fall and winter fruit is added to this insect diet.

In fall and winter, Bluebirds add fruit like that offered by this Flowering Dogwood (Cornus florida) to their diet.

While I focused on this young bird, someone else entered my line of sight.  It was a vividly colorful mature male Bluebird.  He landed in a low bare branch of the Tuliptree, the remnants of last year’s fruit only slightly obscuring my view of him.

Male Eastern Bluebird in Tuliptree (Liriodendron tulipifera)

This dazzling male seemed intent on mesmerizing me with his beauty so that I would forget about his offspring in the shadows behind him.

Male Eastern Bluebird in Tuliptree (Liriodendron tulipifera)

His strategy was pretty effective.  While I didn’t forget about the young bird, I couldn’t take my eyes off its father.

Male Eastern Bluebird in Tuliptree (Liriodendron tulipifera)

But eventually my peripheral vision picked up some movement behind this stunning male.

A female Eastern Bluebird was flying from a nesting box in the meadow, to the far edge of the tree line.  She flew back and forth, until the young bluebird finally followed her and they disappeared together through the trees.  When I looked again for the male, he had also taken off.

I walked to the lawn on other side of the wood line toward the place where the Bluebirds had escaped from my view and found lots of activity.  The female, now with two immature Bluebirds, flew back and forth from the lawn to the trees.  Practice flights?  One of the youngsters decided to stay in the grass, poking at the ground in search of insect food.  Mom stayed for a while, coaching her young student.

Female Eastern Bluebird (left) with tutoring her young offspring

Eventually Mom flew back to the shelter of the trees.  After a moment, the young bird followed the rest of its family, disappearing into the trees.

Young Eastern Bluebird

 

Resources

Eastman, John.  Birds of Forest, Yard, and Thicket.  1997.

Harrison, Hal H.  Eastern Birds’ Nests.  1975

Sibley, David Allen.  The Sibley Guide to Bird Life and Behavior.  2001.

Cornell Lab of Ornithology All About Birds

 

A Winter Show-off

My first encounter with Round-headed Bush Clover (Lespedeza capitata) was in late fall when the warm brown seed heads caught my eye.

Round-headed Bush Clover (Lespedeza capitata)

Throughout fall through winter, this plant is at its most dramatic, easily compelling attention away from nearby vegetation.

Round-headed Bush Clover (Lespedeza capitata)

When in bloom, Round-headed Bush Clover’s appearance is much more subtle, blending in with the grasses, Mountain Mints, asters, goldenrods and other plants that may share its territory.

Round-headed Bush Clover (Lespedeza capitata)

Round-headed Bush Clover has dense clusters, or heads, of small white flowers.  ‘Capitata’ in the scientific name means ‘growing in a dense head’, reflecting this arrangement.  The upper petal of each flower has a bit of an art deco vibe – they’re smudged with pink at the throat with ray-like veins radiating above.  This display may look delicately pretty to us, but to the many bees that visit the flowers it’s a beacon advertising food availability.

Round-headed Bush Clover (Lespedeza capitata)

The flower petals are protected by hairy sepals, green when the flowers are in bloom, then turning deep brown for fall and winter.  It’s these brown sepals that provide the eye-catching winter display.   If Round-headed Bush Clover’s strategy for enticing pollinators to visit is successful, dry (not fleshy) fruits will be tucked inside the dried sepals.

Hairs on plants are often an adaptation to protect the plant from being eaten, or too discourage free-loaders from stealing nectar when the flowers are blooming.  For example, ants visit flowers for nectar but rarely help with pollination because they are not a good anatomical match for the flowers’ reproductive structures, nor do the ants have the type of surface to which pollen might adhere.  The hairy sepals surrounding the flowers are likely to discourage ants from foraging the flowers, preserving the nectar for more effective flower visitors.

Round-headed Bush Clover (Lespedeza capitata)

Round-headed Bush Clover has three-part compound leaves, an arrangement that is common with clovers. It grows to a height of two to five feet (.6 – 1.5 meters).  Although the plant is somewhat shrubby-looking, it is herbaceous, that is, its above ground parts die back in the winter, and new shoots emerge from its roots for the next growing season.

In addition to offering food for pollinators, Round-headed Bush Clover is a food plant for the caterpillars of several butterflies, including the Silver-spotted Skipper,

Silver-spotted Skipper ovipositing (laying an egg) on Pokeweed (Phytolacca americana). Silver-spotted Skippers have the unusual habit of laying their eggs on plants near their caterpillar food plants.

Eastern-tailed Blue,

Eastern-tailed Blue on Butterflyweed (Asclepias tuberosa)

Gray Hairstreak,

Gray Hairstreak on White Clover (Trifolium repens)

Southern Cloudywing, Northern Cloudywing, Confused Cloudywing, Hoary Edge, and the Io Moth.

Dark-eyed Juncos, Mourning Doves, Bobwhites and Wild Turkeys are among the birds that may eat the seeds when they are available.

Dark-eyed Junco

Round-headed Bush Clover is native in most of the eastern two-thirds of the United States, and in Ontario and New Brunswick in Canada.  Searching for it in a meadow near you gives you a reason to go out for a winter walk!

Round-headed Bush Clover (Lespedeza capitata)

Resources

Beadle, David; Leckie, Seabrooke. Peterson Field Guide to Moths of Northeastern North America. 2012.

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Stearn, William T. Stearn’s Dictionary of Plant Names.  1996

Illinois Wildflowers

Natural History Museum Hosts Database

USDA NRCS Plants Database

 

 

Crayon-colored Hickories

Mockernut Hickory (Carya tomentosa)

The compound leaves of Hickory (Carya species) trees still clinging to their branches are displaying colors that remind me of crayons:  yellow-green, yellow-orange, lemon-yellow, chestnut, burnt umber.  Together with the reds and browns of Oaks, the tans and peach of American Beech, they are part of the mid-fall forest pallette.   Shagbark (Carya ovata), Mockernut (C. tomentosa) and Bitternut (C. cordiformis) are the Hickories I encounter most often.

Mockernut Hickory (Carya tomentosa).

Mockernut Hickory (Carya tomentosa).

Those Hickory leaves may have supported up to 200 different species of butterflies and moths as food for their caterpillars, all without any negative impact on the appearance of the trees. Some of the species Hickories support are Banded and Hickory Hairstreak butterflies, and many moths, including Hickory Tussock, Yellow-shouldered Slug, and the dramatic Hickory Horned Devil, the largest of our native North American caterpillars.

Banded Hairstreak on Indian Hemp (Apocynum cannabinum). Banded Hairstreak caterpillars eat Hickory leaves, as well as some other woody species.

Banded Hairstreak on Indian Hemp (Apocynum cannabinum). Banded Hairstreak caterpillars eat Hickory leaves, as well as some other woody species.

Hickory Tussock Moth Caterpillar

Hickory Tussock Moth Caterpillar

Yellow-shouldered Slug

Yellow-shouldered Slug

The aptly named, acrobatic Hickory Horned Devil caterpillar.

The aptly named, athletic, Hickory Horned Devil caterpillar.

All of those caterpillars are fair game for birds, looking for food for themselves and their growing offspring. Insects, especially caterpilIars, are an important source of food for birds.  It can take thousands of caterpillars to raise a hungry clutch of baby birds.

Wood Thrush at the nest with babies

Wood Thrush at the nest with babies

Some caterpillars may fall victim to other predators, like spiders, predatory wasps or flies, and assassin bugs.

Brown Assassin Bug (Acholla multispinosa) on Bitternut Hickory bud.

Brown Assassin Bug (Acholla multispinosa) on Bitternut Hickory bud.

Hickory nuts also supply food for animals, including people. The husks have four sections that split open to reveal the hard shell protecting the nut ‘meat’ inside.

Shagbark Hickory (Carya ovata) nuts

Shagbark Hickory (Carya ovata) nuts

Mockernut Hickory (Carya tomentosa) nuts split partially open, like this one.

Mockernut Hickory (Carya tomentosa) nuts split partially open, like this one.

Hickory nut on the right, empty husk pieces on the left

Hickory nut on the right, empty husk pieces on the left

Eastern Chipmunks, Red, Gray, Fox and Flying Squirrels, Raccoons, and rabbits all eat Hickory nuts. Squirrels may bury some of the nuts rather than eating them right away.  This habit helps to disperse the Hickories if the squirrels don’t come back and eat the nuts at a later date.

Eastern Chipmunk (with full cheeks!)

Eastern Chipmunk (with full cheeks!)

Gray Squirrel

Gray Squirrel

Fox may also eat Hickory nuts, or they may eat the smaller animals who eat the nuts.

Red Fox eating Gray Squirrel

Red Fox eating Gray Squirrel

Wild Turkeys, Bobwhites, Red-bellied Woodpeckers, Blue Jays, Rose-breasted Grosbeaks and even Wood Ducks are among the birds that consume the tastier species of Hickory nuts.

Red-bellied Woodpecker

Red-bellied Woodpecker

Male Wood Duck in non-breeding plumage

Male Wood Duck in non-breeding plumage

Hickory trees provide food and building material for humans, too.   Shagbark is the species whose nuts are most often sold commercially.  As you might guess from its name, Bitternut Hickory is not sought after for its nuts.  Pecans (Carya illinoinensis) are in this same genus and are an important commercial crop.  Hickory sap can be used to make syrup or other sweeteners.

Shagbark is also the species whose wood is most often used commercially for making handles, ladder rungs, wheel spokes, flooring, and a hickory-smoked flavor for cooking. Named for its shaggy strips of bark, Shagbark Hickory stands out from the crowd.

Can you pick the Shagbark Hickory (Carya ovata) out of the crowd?

Can you pick the Shagbark Hickory (Carya ovata) out of the crowd?

The bark offers warm, dry accommodations for insects and others trying survive the winter.

Spider web on Shagbark Hickory (Carya ovata)

Spider web on Shagbark Hickory (Carya ovata)

Eastern Comma butterflies survive the winter as adults, if they can find a warm dry shelter like a space under the loose bark of Shagbark Hickory (Carya ovata).

Eastern Comma butterflies survive the winter as adults, if they can find a warm dry shelter like a space under the loose bark of Shagbark Hickory (Carya ovata).

Mockernut Hickory also has distinctive bark, but in a completely different way. Its gray, smooth-looking, corky exterior forms sinuous ridges along the length of the trunk.

Mockernut Hickory (Carya tomentosa). Notice the curved ridges in the bark, especially in places where branches have fallen off.

Look for Hickory trees even after their leaves fall. You may be able to identify them by their bark and their buds.  Hickories typically have a single large end bud at the tip of their branches that is usually quite distinctive, different for each species.  There are smaller buds spaced alternately along the length of the branches.

Mockernut Hickory buds are somewhat rounded, echoing the curved pattern of the bark ridges.

Mockernut Hickory (Carya tomentosa) branch in winter. Notice the large end bud with rounded sides.

Mockernut Hickory (Carya tomentosa) branch in winter. Notice the large end bud with rounded sides.

Shagbark Hickory usually retains contrasting bud scales, which you might think of as being reminiscent of the shaggy bark.

Shagbark Hickory (Carya ovata) bud. Notice the bod scales hugging the sides.

Shagbark Hickory (Carya ovata) bud. Notice the scales hugging the sides of the bud.

Bitternut Hickory buds are a bright mustard color that is difficult to mistake for anything else.

Bitternut Hickory (Carya cordiformis), showing its distinctive mustard-colored buds.

Bitternut Hickory (Carya cordiformis), showing its distinctive mustard-colored buds.

As winter turns to spring, watch for these buds to swell and unfold like flowers.

Mockernut Hickory (Carya tomentosa) leaves unfolding in spring.

Mockernut Hickory (Carya tomentosa) leaves unfolding in spring.

Shagbark Hickory (Carya ovata) in spring

Shagbark Hickory (Carya ovata) in spring

The range for Shagbark and Bitternut Hickory includes much of the eastern two-thirds of the United States, and Ontario and Quebec provinces in Canada. Mockernut’s range is similar, but it does not include the Canadian provinces, or some of the northern tier of the United States.

Enjoy the colorful foliage while it lasts!

Mockernut Hickory (Carya tomentosa)

Mockernut Hickory (Carya tomentosa)

Related Posts

Nutritious Fall Foliage: What Makes Leaves So Colorful

American Beech

In Praise of Black Walnut Trees

Resources

Cech, Rick; Tudor, Guy. Butterflies of the East Coast.  2005.

Eastman, John. The Book of Forest and Thicket.  1992.

Marshall, Stephen A. Insects Their Natural History and Diversity. 2006.

Martin, Alexander C.; Zim, Herbert S.; Nelson, Arnold L. American Wildlife & Plants A Guide to Wildlife Food Habits.  1951.

Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania.  2007

Stearn, William T. Stearn’s Dictionary of Plant Names.  1996

Tallamy, Douglas W. Bringing Nature Home.  2007

Wagner, David L.; Caterpillars of Eastern North America, 2005.

Illinois Wildflowers
http://www.illinoiswildflowers.info/trees/plants/btnt_hickory.html
http://www.illinoiswildflowers.info/trees/plants/mock_hickory.html

Tallamy, Douglas W. Bringing Nature Home

USDA NRCS Plant Database
https://plants.usda.gov/core/profile?symbol=CAOV2
https://plants.usda.gov/core/profile?symbol=caco15
https://plants.usda.gov/core/profile?symbol=CAAL27

The Wood Database