Is Connecticut Their Florida?

Retirees who want to escape the cold and ice to spend the winter down south are known as “snowbirds.” Actually, this nickname describes the Dark-eyed Junco (Junco hyemalis). Juncos are arriving here now after spending the summer nesting in the mountains of New England and in the Canadian Boreal Forest. They will head back north next spring. In winter they feed on seeds of plants many of us consider “weeds,” including Chickweed (Stellaria media), Lambsquarters (Chenopodium album), and Wood Sorrel (Oxalis stricta). You will also see juncos at feeders. With their slate-gray backs and upper bellies, and white outer tail feathers that flash as they fly away, they are easy to spot.

Besides migrating south, Dark-eyed Juncos (Junco hyemalis) also undergo a vertical migration, nesting on mountain tops and wintering in the valleys. Photo by Mykola Swarnyk, CC BY-SA 3.0 <;, via Wikimedia Commons

The smallest bird of the winter woods, not much larger than a Ruby-throated Hummingbird (Archilochus colubris), is the Golden-crowned Kinglet (Regulus satrapa). This species spends the summer nesting in northern coniferous forests but lives in a variety of forest habitats here in winter. I’ve even seen it flitting among the oaks growing along New Haven streets. Being so small, it is in constant motion, continually foraging for wintering insects and their eggs among bark and branches to fuel its metabolism. It would starve if it could not find food for a few hours on a cold day. Listen for its call, a high-pitched “tseet-tseet-tseet,” as it feeds.

“Energizer Bunnies” of the bird world, Golden-crowned Kinglets (Regulus satrapa) are constantly moving looking for food to fuel their high metabolism. Photo by Melissa McMasters from Memphis, TN, United States, CC BY 2.0

White-throated Sparrows (Zonotrichia albicollis) are arriving now. You can tell this bird from other sparrows by its black and white (sometimes tan) striped head and white throat. Look for them on the ground in woods and brushy edges. They can also be easily identified by their loud “chink” call. The White-throated Sparrow is one of the few birds that sings during the winter. Listen for its plaintive “Old-Sam-Peabody-Peabody” song. You will see both Dark-eyed Juncos and White-throated Sparrows on the ground under your bird feeders.

White-throated Sparrows (Zonotrichia albicollis) are a larger, quite vocal winter visitors told from other sparrows by their white throats and black and white-striped caps. Photo by Ryan Hodnett, CC BY-SA 4.0 <;, via Wikimedia Commons.

Some bird species that usually stay north in the winter will fly south during an irruption, a mass movement to another location that occurs periodically. An irruption is happening this year for some of these boreal migrants. Rather than being due to cold temperatures, this movement is actually tied to food availability. When the fruit and seeds of spruces, pines, mountain ash, and other trees are scarce in the north, some birds seek food elsewhere. The Winter Finch Forecast (maintained for decades by biologist Ron Pittaway, who recently passed the torch to Tyler Hoar) uses reports from foresters, researchers, naturalists, and other observers about the northern tree seed crop to predict which bird species will fly south or west.

Boreal migrants spotted at feeders here recently confirm this forecast: the Purple Finch (Haemorhous purpureus), Pine Siskin (Spinus pinus), and another migrant (not a finch), the Red-breasted Nuthatch (Sitta canadensis).

You can tell a male Purple Finch from the more common male House Finch (Haemorhous mexicanus) by the deeper color on the Purple Finch’s head and upper back—it looks as if it was dipped in raspberry juice. The male House Finch’s more reddish head color does not extend down its back. Purple Finches like to eat black oil seed at feeders.

Another boreal migrant during irruptions includes the Purple Finch. Males can be told from the more common male House Finches by looking like they were dipped in raspberry juice, rather than the male House Finches more reddish head and upper belly. Both female Purple Finches and House Finches look very similar, but female Purple Finches are more stockier looking and have darker streaks along the belly. Photo by Melissa McMasters from Memphis, TN, United States, CC BY 2.0 <;, via Wikimedia Commons.

Red-breasted Nuthatches travel in mixed flocks with Black-capped Chickadees (Poecile atricapillus), Downy Woodpeckers (Picoides pubescens), and Golden-crowned Kinglets. Unlike the larger, resident White-breasted Nuthatch (Sitta carolinensis), the Red-breasted Nuthatch has a reddish belly and black eye stripe. Its call is more nasal and higher pitched. Both species are called “upside-down birds,” as they often walk down a tree’s bark hunting for insects. They will take sunflower seeds, peanuts, and suet at feeders.

Next time you see a bird looking for food by walking upside down on a tree trunk, look to see if it has a reddish belly and black stripe through its eye. you may have spotted the less common Red-breasted Nuthatch (Sitta canadensis). Photo by Wolfgang Wander, CC BY-SA 3.0 <;, via Wikimedia Commons.

Pine Siskins are very gregarious and often travel and feed in flocks. This brown, streaked bird with yellow on the edges of its wings and tail is better identified by its harsh, ascending “zrweeet” call. If they are around, you will see them at thistle feeders.

Pine siskins (Spinus pinus) are rather non-descript, brown and white striped birds with a touch of yellow on their outer wings and tails. They usually travel in flocks and can suddenly arrive at feeders. Photo by dfaulder, CC BY 2.0 <;, via Wikimedia Commons.

Not every Blue Jay (Cyanocitta cristata) that you will see this winter is a permanent resident here. About a quarter of Blue Jays are migrants from northern climes. At this time of year, I often see them flying over highways as they migrate.

Blue Jays (Cyanocitta cristata) are often taken for granted but they really are a beautiful bird. The birds you see in the fall and winter here might have migrated here from the north. Photo by Mdf, CC BY-SA 3.0, via Wikimedia Commons.

It’s a great time of year to observe these colorful visitors from the north. Put out a bird feeder or two and enjoy them.

They Get Around

If you’ve ever had to remove burrs from your pants after a hike or from your dog’s ear after a walk, you know what I’m talking about. The different ways plants have evolved for dispersing their fruits and seeds are truly remarkable. All for the sake of reproducing their species, seeds are adapted in different ways to travel by land, air, and sea—and in some cases, to even launch themselves on their own incredible journey through the digestive tracts of birds and other animals.

There are several ways seeds are dispersed: by hitchhiking on fur or clothing; by becoming airborne; by exploding from pods; by being carried in water; by being digested by birds, fish, and other animals; and by being buried.

While walking along the edge of my property a few days ago, I brushed up against some plants and found several “hitchhikers” attached to my jeans. They were Stick-tights (Desmodium cuspidatum). Their small, flat, green triangular seeds, which have tiny hooks that attach to the fur of many mammals, eventually find a new place to germinate. Devil’s Beggar-ticks (Bidens frondosa), with its two-pronged hooks, is another hitchhiker.

Stick-Tights seeds (Desmodium sp.) on a sneaker. Notice the small hairs. Photo by Jud McCranie / CC BY-SA (

We all have blown the ripe seeds of Dandelion (Taraxacum officinale) or thrown the ripe seeds from milkweed pods to watch them float away. A “parachute” attached to your seed can certainly spread you far. Other seeds have wings that act like whirligigs or helicopters, such as the double-winged samaras of maples (Acer spp.) that spin to get away from the parent tree and hopefully finding good ground in which to germinate. There is a seed attached to each wing.

The orchid family has the world’s smallest seeds. Seeds such as these from Vanilla (Vanilla planifolia) don’t have an endosperm with food reserves so they need to disperse in the air and reach soil that contains fungi, which supply resources for germination and growth. Fingers and photo by Patrick Sweeney.

Researchers have documented incredible long-distance dispersals of plants and fungi on the feathers of birds. Microscopic spores of mosses, liverworts, and fungi have been found on the primary feathers of three bird species: Semi-palmated Plover (Charadrius semipalmatus), Red Phalarope (Phalaropus fulicarius), and American Golden-Plover (Pluvialis dominica). These birds migrate from the Arctic to South America. Those spores were still alive when the birds arrived at their destinations. When the birds molt their feathers the spores contact the ground and germinate.

Native to Connecticut, Jewelweed, also called Touch-Me-Not (Impatiens capensis), has a more explosive tendency. As the fruits dry out, mechanical energy stored in valves in the fruits cause them to coil inward, collapse the fruit pods, and eject the seeds. If you touch the slender seed pods, which are ripe now, you will see the seeds explode out of the pods, sometimes traveling up to 8 feet (2.5 meters) or more. Jewelweed spreads easily as a result. And it’s a good thing, because the flowers are an important source of nectar for migrating hummingbirds. The ripe white berries of dwarf mistletoes (Arceuthobium spp.), native to the western United States and Canada, also explode, ejecting seeds at an average speed of 60 miles (96.5 kilometers) per hour and scattering them as far as 50 feet (about 15 meters). The Eastern Mistletoe (Phoradendron leucarpum), native to southern North America is not nearly so dramatic. Its seeds are dispersed when birds eat its fruit, leave seeds in droppings and also wipe the sticky seeds from their bills on tree branches, where they can germinate.

The seed of the Coconut Palm (Cocos nucifera) can float in saltwater for up to a year before seeding itself on a southern sandy shore. The “seeds” of the Red Mangrove (Rhizophora mangle) actually germinate and become seedling propagules before dropping off the parent tree. They are dispersed by water and eventually embed themselves in the shallows.

Patrick Sweeney, Senior Collections Manager for Botany at the Yale Peabody Museum, is holding a Double Coconut or Coco de Mer (Lodoicea maldivica) the world’s largest seed. There are various theories as to why the seed evolved to be so large. The giant seeds drop near the parent and have the food resources to grow in the shade and develop a long petiole to reach light. Photo by Larry Gall.

There is a well-known relationship between the Yellow-rumped Warbler (Dendroica petechia) and the flowering shrub Small Bayberry or Wax Myrtle (Morella caroliniensis). When these warblers eat these berries, the birds’ gizzards scarify the seeds and their droppings help to fertilize them, ensuring germination. These birds were once called Myrtle Warblers.

Besides eating the blue, berry-like cones of the Eastern Red-Cedar (Juniperus virginiana), Cedar Waxwings (Bombycilla cerdrorum) love to eat the red berries of Mountain-Ash (Sorbus sp.), thereby spreading the tree’s seeds. Photo by Mike’s Birds from Riverside, CA, US / CC BY-SA (

Other seeds such as acorns rely on animals like squirrels, chipmunks, and even crows to bury them. If the animal does not return to its stash, the seeds may germinate. To attract wildlife, plants like blackberries and raspberries surround their seeds with a brightly colored and sweet tasting pulp. Even ants get into the act. The seeds of the spring wildflower Bloodroot (Sanguinaria canadensis) have elaiosomes, fatty attachments that attract ants. The ants will carry seeds to their nest and eat the elaiosomes. The seeds then have a fertile place to germinate.

Seed of Jeffersonia diphylla (Twinleaf; Berberidaceae) with a white or yellowish appendage called an elaiosome. This fat body attracts ants, which carry the seed to their nest. Seed dispersal by ants is known as myrmecochory. Photo by Hans Stuessi / CC BY (

Why do these seed dispersal adaptations exist? There are several reasons. Often, the survival rate of a seed improves away from the parent plant, because it competes less with the parent and, in cases where predators are attracted to a clump of newly germinated plants clustered around a parent plant, it is less likely to be eaten. These adaptations allow plants to reach specific habitats that are more favorable for survival, a hypothesis known as directed dispersal. Adaptations that favor dispersal on a more distant scale allow plants to colonize new and vacant habitats or regions, reducing a plant’s risk of predation and increasing its chances for survival.

So, the next time you spy a Jewelweed “popper” go ahead, give it a pinch and watch those seeds fly! You’ll be helping seeds do what they were meant to do—and besides, it’s fun.

Hawk Heaven

Look up! It’s happening right now, right over your head. It’s the autumnal migration of raptors—hawks in particular. And it is one of nature’s most impressive animal migrations.

When I was a child, I asked my mom to take me to Hawk Mountain. It was a two-hour drive from where we lived in northern New Jersey to Kempton, Pennsylvania, but she was determined to help fuel my passion for nature and off we went. It was a sunny early November day when we arrived at the North Lookout. Just as we got there a Golden Eagle (Aquila chrysaetos) flew by us at eye level. The sun lit its seven foot wingspan as if it was on fire. I’ve been hooked on hawks ever since. Every year I watch for them as they pass through our area.

Cooper’s Hawks (Accipiter cooperii) are in a group of hawks called accipiters. Their short, rounded wings and long tails are adaptations for darting through forests and catching birds, their primary prey. Cooper’s hawks can be told from similar Sharp-shinned hawks (Accipiter striatus) by having a larger head and a longer, round-tipped tail. Photo by Dominic Sherony / CC BY-SA (

Hawks, falcons, ospreys and vultures can be seen migrating here from the end of August through mid-December, although the greatest diversity of species can be seen now through the end of the month. The birds take advantage of warm, spiraling air currents called thermals, which allow them to rise thousands of feet. They “hop scotch” south, gliding from one thermal to the next. There are two migration paths or flyways these raptors tend to follow in Connecticut. They catch updrafts and thermals along the Northwest Hills and use thermals to follow the coastline. Some Ospreys (Pandion haliaetus) and Peregrine Falcons (Falco peregrinus) bypass the land routes south and fly across the Atlantic instead. These birds are heading to the northern South American coast.

Ospreys can be told from other hawks in flight by having “crooked” wings and dark “wrists.” The majority of ospreys fly through our area earlier in the migration, mostly during September. Photo by U. S. Fish and Wildlife Service – Northeast Region / Public domain.

Weather can really influence raptor flight on any given day. The best conditions occur on certain kinds of days, such as after a cold front passes through, and on days with northwesterly winds. On a windy day they fly from dawn to dusk.

Red-shouldered hawks (Buteo linneatus) are in a group of hawks called buteos. Their wide, rounded wings and fan-shaped tails are great adaptations for soaring. Red-shouldered hawks can be told in flight from larger Red-tailed Hawks (Buteo jamaicensis) by their quicker, choppier wing beats and translucent, white, crescent-shaped patches on the primary feathers, seen here on the left wing of this bird. Photo by Andy Morffew from Itchen Abbas, Hampshire, UK / CC BY (

Although in good conditions you might see hawks overhead anywhere, there are some great viewing hotspots in Connecticut. One of the best is Lighthouse Point Park in New Haven. Quaker Ridge Hawk Watch at Greenwich Audubon is another great site. Other places to watch are included here.

Many of North America’s fall raptor migratory routes converge at Veracruz, Mexico. There a small section of coastal plain is constricted between the mountains of the Sierra Madre and the Gulf of Mexico. At two raptor watching sites counts can top 100,000 birds in one day! It is the greatest raptor flyway in the world.

There are various tricks to identifying hawks, falcons, ospreys, and vultures in flight. The Cornell Laboratory of Ornithology’s All About Birds is a great site for identification. To test your knowledge, you can try a quiz.

Now’s the time to see this amazing wildlife spectacle. The next time a cold front passes through or winds blow from the northwest, grab your binoculars and look up.

Autumn Colors Were Already There, Mostly

They’re changing now.

It’s that time here in Connecticut when deciduous trees change color and add drama to our forests and landscapes. Most of the colors we see in beautiful autumn foliage have been there all along. As day length and temperature decrease, the cells between the leaf and the petiole (stem) develop a corky abscission (separation) layer that begins to block materials coming into and going out of the leaf. As a result, leaves stop making new chlorophyll (the green pigment that makes energy for the plant using sunlight, carbon dioxide, and water) and their green color fades. The leaf’s yellow and orange pigments, called carotenoids, then show through. Yellow leaves from trees such as Witch Hazel (Hamamelis virginiana) are a good example.

Sweet Pepperbush’s (Clethra alnifolia) bright yellow leaves are caused by the carotenoid pigment called xanthophyll. This color was masked during the summer by the green chlorophyll. Photo by Andy Brand.

Some pigments are produced later by chemical changes and weren’t there all along. Anthocyanins give rise to the brilliant reds in the Sugar Maple (Acer saccharum), Sumac (Rhus spp.), and Northern Red Oak (Quercus rubra) and to the red-purplish color in Flowering Dogwood (Benthamidia florida).

The intense red, fall foliage of the Sugar Maple is caused by the pigment anthocyanin. Photo by Sarah Bailey

Weather certainly affects the intensity of colors. The drought we have been experiencing has stressed our trees. Some lost their leaves early or started turning color prematurely. So fall foliage will not be as vibrant. Adequate summer rains promote healthy trees that hold onto their leaves longer and thereby have richer autumn colors.

The right fall weather can cause anthocyanins to produce vibrant reds. This pigment needs sunlight for color production and the colors are enhanced by sunny days and cool nights. This is why fall color is so outstanding in the colder climes of Vermont and other areas of northern New England.

Owen Reiser, a biology and mathematics student from Southern Illinois University, filmed leaf color changes using time-lapse photography.

The purpose of leaf color is still shrouded in mystery, especially for the anthocyanins. Researchers have proposed various hypotheses. A physiological explanation is that anthocyanins act like a sunscreen, allowing the tree to better reabsorb nitrogen as chlorophyll is broken down. Nitrogen helps the plant in the next growing season. There is evidence is that redder leaves have less nitrogen when they fall from the trees, compared with leaves without anthocyanins.

The fall foliage of some kinds of plants is consistent every year. Leaves of the Oak-leaved Hydrangea (Hydrangea quercifolia) are usually maroon. Photo by Adam Wheeler, Broken Arrow Nursery.

One biological explanation is that color is camouflage for leaves to keep them from being recognized and eaten. Or the bright leaf colors may be an adaptation to dissuade insects from laying eggs if they think the leaves are toxic, thereby minimizing damage to the plant the following year. Another possible explanation is that bright colors are a flag to draw animals to eat the fruit and so disperse seeds away from the tree. Poison Ivy (Toxicodendron radicans) is thought to be an example of this—its bright red leaves in the fall may be a signal to birds that the plant’s white berries are ripe.

The red leaves of Poison Ivy'(Toxicodendron radicans) may be a signal to birds that its white berries are ripe and ready to eat. Photo by Famartin / CC BY-SA (

Rather than raking, bagging, and putting your leaves to the curb, put them to good use. Remember that leaves make an outstanding mulch under your trees and shrubs and create important overwintering sites for native moths that provide food for birds for next year’s nesting season. You can easily make a leaf mulch container by a bending a four-foot (1.2 meter) high section of hardware cloth into a large circle supported with two stakes. Fill it with your leaves and by next summer or fall you’ll have an excellent mulch to add to your garden beds through the growing season.

Happy leaf peeping.

Plant Extra Parsley Next Spring

Last week I found some late stage, or instar, Black Swallowtail caterpillars on my parsley plants. I couldn’t believe that I missed seeing them earlier. If you have sunny, meadow-like areas nearby, as well as gardens with flowering perennials, there a good chance you’ll see them, as these are the larvae of the most common swallowtail butterfly in the United States. I’ve seen Black Swallowtails laying eggs on my Fennel (Foeniculum vulgare) and they may have laid eggs on my Parsley (Petroselenium crispum) too. Or I might have brought home these larvae on parsley I purchased from the nursery.

Black swallowtail larvae go through five instars or stages. Here is a fifth instar forming the characteristic “J'” shape which is just before changing into a chrysalis. Notice the yellow spots on a greenish background compared to the Monarch butterfly larva below. Photo by (c)2009 Derek Ramsey (Ram-Man) / GFDL 1.2 (
Monarch larvae have yellow, black and white stripes. Photo by USFWSmidwest / Public domain.

I put my pots of parsley with the caterpillars under a screened laundry basket to protect them from parasitic flies. Each one has now transformed into a grey pupa, or chrysalis, and will spend the winter there. I will release the butterflies in the spring after they eclose, or hatch into adults.

The Black Swallowtail’s second generation spends the winter as a pupa or chrysalis and will hatch in the spring. This one is attached to a screen laundry basket. Photo by the author.

Both fennel and parsley are members of the carrot family (Apiaceae). Black Swallowtails also lay eggs on other members of this plant family, including Queen Anne’s Lace (Daucus carota) and Dill (Anethum graveolens). The larvae also feed on some members of the Rutaceae, or citrus family, such as Common Rue (Ruta graveolens). I find it interesting that some companies push insecticides to kill the “parsley worm” in the garden. Insecticides have no place in a wildlife garden for native bees and butterflies (not to mention on herbs that you plan to eat). Many homeowners are not aware of what a beautiful butterfly this larva will become. That’s why I say plant a little extra parsley for the Black Swallowtails.

Before other plants from this family were introduced in the United States for gardens, the traditional larval food plant in the region for swallowtails probably included two species of the Connecticut native perennial Golden Alexanders, including Common Golden Alexanders (Zizia aurea) and Heart-leaved Golden Alexanders (Zizia aptera).

Common Golden Alexanders is typically found in floodplains, meadows ,and on the shores of rivers and lakes. But Heart-leaved Golden Alexanders is rare in New England and is a state-listed endangered species in Connecticut. It loves calcium-rich, or calcareous, soils and in Connecticut has been found growing on precolonial Native American shell middens, which are piles of leftover oysters, mussels, and clams.

Common Golden Alexanders (Zizia aurea) is a larval host plant for Black Swallowtails in the wild. Photo by
(c)2007 Derek Ramsey (Ram-Man) / GFDL 1.2 (

Black Swallowtails usually have two generations per year. After spending the winter as a chrysalis, the first generation hatches between late April and early June. The egg stage lasts four to nine days, the larval stage 10 to 30 days, and the pupal stage 9 to 18 days (in the first generation). 

A Black Swallowtail caterpillar begins life with all the unappealing appearance of bird poop—all black with a white stripe across its midsection. Many butterfly larvae have early life stages that mimic bird droppings as a protection from predators. There is also mimicry in the adults. The color of the adult Black Swallowtail mimics the coloration of the Pipevine Swallowtail (Battus philenor), a toxic species, and therefore the Black Swallowtail gains some protection from bird predation.

The first two Black Swallowtail instars mimic bird droppings to keep from getting eaten by predators. Photo by Jacy Lucier / CC BY-SA (

Adult Black Swallowtails will come to a host of plants to find nectar, including native perennials such as Meadow Phlox (Phlox paniculata), Wild Bergamot (Monarda fistulosa), milkweeds such as Butterfly Weed (Asclepias tuberosa) and Swamp Milkweed (Asclepias incarnata), and annuals such as Zinnia and Cosmos.

Black Swallowtail males have rows of large yellow spots on the upper wings. Notice the fake “eyes” on the hind wings, which can direct a bird’s bite there instead of the head. Photo by D. Gordon E. Robertson / CC BY-SA (
Black Swallowtail females have smaller rows of yellow spots and much more blue on the hind wings. Photo by Kenneth Dwain Harrelson / CC BY-SA (

Adult male butterflies can use lek mating, in which a bunch of males will wait near larval food plants for females and display there for them.

Through natural succession, many of Connecticut’s habitats eventually change over time and become mature forests. Meadows, however, provide key habitats for a host of species, including Black Swallowtails. You can add to or create your own mini-meadow in a perennial garden bed in your yard or neighborhood by planting Golden Alexanders and adding some parsley, dill, or fennel in the summer. Plant it and they will come.

Oaks Are Mighty

Planting an oak tree in your yard can do more for wildlife than a perennial border of native plants.

Oaks are a keystone species. They profoundly influence other species in our forests. North American oaks provide food and shelter for more species than any other tree group and form the backbone of many different forest communities. Here in Connecticut, there are 470 species of Lepidoptera (butterflies and moths) whose larvae eat oak leaves.

This Funerary Dagger Moth larva (Acronicta funeralis) is just one of the 470 species that feed on oaks.

Having a bunch of larvae, or caterpillars, eating the leaves of your oak tree may not appeal to you, but if you are a bird, it certainly would! More than 90% of forest-nesting birds feed butterfly and moth larvae to their young. The woods across from our house are filled with Northern Red Oak (Quercus rubra) and White Oak (Quercus alba) trees. In early May, these trees are loaded with neotropical birds like warblers, whose migration is perfectly timed with the larval hatch.

The Charter Oak, oil on canvas, Charles De Wolf Brownell, 1857, Public Domain. Wadsworth Athenaeum.

The Charter Oak was a very large White Oak which grew on Wyllys Hyll in Hartford. It may have dated back to as early as the 12th century but succumbed to a wind storm on August 21, 1856. Legend has it that Connecticut’s Royal Charter of 1662 was hidden in a hollow of the tree to keep it from being confiscated by the English governor-general. This symbol of American independence is commemorated today on the Connecticut State quarter.

Acorns are falling from trees now. This year doesn’t seem to be a mast year. In a mast year, which happens every few years, oaks produce far more acorns. This could be because larger numbers of acorns might overwhelm predators and ensure more acorns germinate and survive.

Northern Red Oak leaves have pointed lobes and rounded acorns with a cap which looks like a fedora. Photo by Dcrjsr / CC BY (

White Oak acorns germinate immediately on falling into the leaf litter, whereas Northern Red Oak acorns need a cool, moist period and won’t sprout until the spring.

White Oak leaves have rounded lobes and oblong acorns with caps which extend lower than red oak acorns, like ski hats. Photo by Alouis21 / CC BY-SA (

Did you ever wonder why there are more red oaks than white oaks? You can thank an Eastern Gray Squirrel (Sciurus carolinensis). Acorns from the Northern Red Oak have more tannin, a bitter chemical that protects the acorns from insects and other predators. White Oak acorns have less tannin and so are “sweeter.” Peter Smallwood, associate professor of biology at the University of Virginia, and Michael Steele, professor of biology at Wilkes University, have found that squirrels eat 85% of white oak acorns shortly after finding them, but store about 60% of the acorns of red oaks. 

This Eastern Gray Squirrel is eating the sweeter White Oak acorn and not bothering to bury it for later. Photo by Paul Johnston / CC BY (

Gray squirrels bury acorns in different places, which is called scatter hoarding. It is thought that they use both their memory and landmarks to find their caches. When a squirrel grabs an acorn, it often does a quick head flick and turns the nut several times in its paws and mouth. These behaviors help the squirrel determine the nut’s freshness and weight, as lighter acorns are often infested with acorn weevils. But, as we know, squirrels don’t remember where all their acorns are, so we can thank them for planting new trees.

Oaks need our help. Some stands of oaks have been hit hard by invasive species. There have been major Gypsy Moth (Lymantria dispar) infestations in the last few years, particularly in eastern Connecticut. Oak wilt is a vascular plant disease caused by the fungus Bretziella fagacearum. This fungus grows on the outer sapwood and restricts the flow of water and nutrients through the tree. It has infected many oaks in the eastern United States, particularly the red oak group, and has been recently confirmed in eastern New York, including on Long Island. To help control the spread of oak wilt, please don’t move firewood long distances.

If you are thinking of planting a tree, consider planting an oak. Your grandchildren will enjoy its shade and the wildlife around it will flourish. Although oaks take a long time to mature, they have an average growth rate when young. As philosopher and author Matshona Dhliwayo says, “an oak tree is a daily reminder that great things often have small beginnings.”

Recalling Charlotte

Malevolent, scheming, horrid, wretched, malignant, hideous, and nasty. When you google words for spiders, these are what come up. Spiders need a good PR firm.

I find the distain for spiders interesting, given that one of the most beloved children’s books of the past two generations is E.B. White’s Charlotte’s Web. This could be a learned behavior. White wrote:“I think it is too bad that children are corrupted by their elders in this hate campaign. Spiders are skillful, amusing, and useful, and only in rare instances has anyone come to grief because of a spider.”

Now is the time of year when we often see orb-weaver spiders of the family Araneidae, the third largest of the spider clan. The Barn Spider (Araneus cavaticus) likes to build webs around human structures. This is the species White noticed in his barn in Maine and whose egg case he brought back to his apartment in New York City.

The spider E.B. White wrote about in Charlotte’s Web is based on the Barn Spider (Araneus cavaticus). Photo by Kilarin / CC BY (

The Black and Yellow Argiope or Yellow Garden Spider (Argiope aurantia) is a common and sizeable orb weaver often seen in meadows. Although large, it is not aggressive and will only bite if grabbed or stepped on. Its bite is like a bee sting. Once mated, the female Argiope produces a ball-shaped egg sac that is up to an inch (2.5 centimeters) in diameter. She’ll guard her eggs on her web as long as she can through the fall, when she’ll die. Come spring up to 1,000 spiderlings will hatch. They will spin a long strand of silk that catches in the wind and so disperse. This is called ballooning and spiderlings have been known to be taken into the jet stream. They have been detected by weather balloons collecting air samples at 16,000 feet (5 kilometers)!

The Black and Yellow Argiope or Yellow Garden Spider (Argiope aurantia) is frequently seen in meadows. Photo by Judy Gallagher / CC BY (

When people think of spider webs, they usually have in mind webs from orb weavers. Each evening these spiders consume their old web, then make a fresh one by spinning a strand of silk that floats to a nearby shrub or other surface. The spiders drop a line from the center, making a “Y,” then create “spokes” of plain silk and concentric rings of sticky silk. The non-sticky spokes let them travel around their web more quickly to subdue prey. Try touching the spokes and rings sometime to feel the difference.

An orb web from the family Araneidae. The radiating “spokes” are not sticky and let the spider travel quickly to secure prey. The concentric circles are sticky and catch prey. Photo by Beatriz Moisset / CC BY-SA (

Spider silk has extremely strong tensile strength, comparable to steel. We humans have put that strength to use in many ways. Spider silk has been used as crosshairs in telescopes, microscopes, and telescopic rifle sights. Different methods of producing spider silk, such as combining with silk from silkworm moths, has created such products as ballistics armor, athletic footwear, personal care products, breast implant and catheter coatings, insulin pumps, and outerwear.

When an insect flies into a web, orb weaver spiders bite their prey, inject venom, then use silk to wrap the prey. They also spin a zigzag pattern of silk, called a stabilimentum, in the center of the web. There is debate about the purpose of this. Possibly it’s meant to warn birds away from the web, as a lure for prey, or to decrease the visibility of the web to insects, making it harder for prey to avoid the web.

The stabilimentum is a zig-zag patterned part of the web; there are different theories as to its purpose. Photo by Rhododendrites / CC BY-SA (

Orb weavers and other spiders are important in ecosystems. They not only prey on species we consider to be garden pests, but in turn they are food for many other species. For example, much of the diet of Ruby-throated Hummingbirds (Archilochus colubris) includes spiders. Ruby-throats use spider silk to weave lichen into their nests.

Give spiders a chance—they are amazing creatures. And as my wife will avow—anything that eats mosquitoes is OK.

You’ve Got Gall

It’s the science of cecidology. Now there’s a Scrabble word for you! Cecidology is the study of plant galls (cecidia).

What are galls? They are a kind of growth or swelling on the external tissues of plants, fungi, or animals. When leading nature walks I am often asked about growths on leaves and stems. Many of these galls are often characteristic in size, shape, and color and can be easily identified. It’s what causes them that is not always apparent. Viruses, bacteria, fungi, insects, mites, and more, can all produce galls.

Plant galls caused by insects are usually a reaction to the larvae of midges (a type of fly), wasps, or aphids that tunnel into the leaf or plant stem. After being disturbed by the insect, the plant’s cells rapidly divide and often provide food and protection for the developing insect. Scientists don’t know all the details of how this happens. On a walk along the Farmington Canal Heritage Greenway in Hamden, I recently found an Oak Apple Gall blown off an oak tree during a recent storm. Oak Apple Galls are found in North America and Europe and form most often on members of the red oak group.

An Oak Apple Gall showing the tiny exit hole of the wasp Amphibolips confluenta.

Here in the East, this gall is caused by the wasp Amphibolips confluenta. The wasp’s life cycle begins when it lays eggs underground among the roots of the tree. The eggs hatch and the larvae feed on these roots. They develop into pupae. Wingless adult females hatch, or eclose, in spring of the second year. They emerge from the ground and climb up the oak tree to the leaves. There the female injects an egg into the veins of a newly growing leaf. Chemicals and hormones released by these eggs alter the leaf’s typical growth, causing galls to form. The round galls create homes and food for the tiny wasp larvae and usually give protection from predators. In midsummer the larvae pupate, then the adults hatch and tunnel their way out. Males and females mate and females lay eggs in the ground to begin the cycle again. A video by Sir David Attenborough shows the fascinating life cycle of a British gall wasp species.

Oak galls are full of tannin. In Europe they have been used to make ink since the Roman Empire. Iron gall ink was made by mixing tannins with iron sulfate and gum arabic. It was the main medium used for writing from the Middle Ages to the early twentieth century.

In British folklore, if a “worm” (insect larva) is found inside a gall on Michaelmas Day, then it will be a good year. If a spider is inside, then it will be a bad year with food shortages and ruined crops. I guess spiders were persecuted long ago too!

Oak Apple Day is a former British holiday that was celebrated on May 29. It commemorated the restoration of Charles ll in 1660. Charles hid in an oak tree during the English Civil War.

You will often find different galls on goldenrods in our area. The Goldenrod Bunch Gall is caused by the gall midge Rhopalomyia solidaginis. This fly is a specialist on Canada Goldenrod (Solidago canadensis). The female Goldenrod Gall Fly (Eurosta solidaginis) lays her eggs in the stems of several goldenrod species, which then form the characteristic ball-shaped Goldenrod Ball Gall. The larva first tunnels an exit hole and then travels back to the center of the ball to spend the winter there. If you ever find a ball gall that looks like the hole has been enlarged, it’s usually the work of Black-capped Chickadees (Poecile atricapillus) and Downy Woodpeckers (Picoides pubescens), which eat these larvae.

Goldenrod Bunch Galls are only found on Canada Goldenrod (Solidago canadensis). Photo by the author.
The tiny midge Rhopalomyia solidaginis is what causes bunch galls to form on Canada Goldenrod. Photo by Beatriz Moisset / CC BY-SA (
You can often find Goldenrod Ball Galls which have their exit holes pecked open by Black-Capped Chickadees and Downy Woodpeckers. Photo by UMN Arboretum.

Other galls include the Witch Hazel Cone Gall, which looks like reddish witch’s hats on the leaves of Witch Hazel (Hamamelis virginiana). They are caused by the aphid Hormaphis hamamelidis.

Witch Hazel Cone Galls are caused by the aphid Hormaphis hamamelidis and resemble red witch’s hats.

The mite Eriophyes cerasicrumena causes the finger-like galls on the leaves of Black Cherry (Prunus seratina).

Black Cherry Finger Galls are caused by the mite Eriophyes cerasicrumena. Photo by Judy Gallagher / CC BY (

Pine Cone Willow Galls really look like a pine cone. They are are usually found on the terminal buds of some species of Willows (Salix sp.) and are caused by the midge Rhabdophaga strobiloides.

Willow Pine Cone Galls really do look like pine cones, but they are not! Photo by Ryan Hodnett / CC BY-SA (

Most galls don’t affect a plant’s health and it’s not necessary to control them. Only a few, such as those triggered by fungi, can actually damage trees by causing branch dieback. Remember that galls are part of the plant and the life supported by them are also part of the ecosystem.

The Reigning Butterfly

They can travel 3,000 miles on a migration. They can glide at an altitude of 11,000 feet. You probably know them well, but there is more to them than meets the eye. The Monarch butterfly (Danaus plexippus) can surprise you.

Monarch butterfly on Zinnia, an annual that attracts many butterflies and other pollinators. Photo by the author.

Monarchs are naturally poisonous to predators, because the milkweeds their larvae eat contain cardiac glycosides, a heart poison. Their bright orange color is aposematic, warning predators that the butterflies are toxic. It was always thought that the Viceroy butterfly (Limenitis archippus) was a non-toxic mimic of the toxic Monarch, an adaptation known as Batesian mimicry. It turns out that both species are toxic! When one toxic species imitates another one, that’s called Müllerian mimicry.

Both Monarch (left) and Viceroy (right) butterflies concentrate their toxins in their wings, where they are likely to be bitten by predators. They are an example of Müllerian mimicry, where one toxic species mimics another toxic species and both gain protection from predators. Photo by
PiccoloNamek (2005-08-22, uploaded by User:Lokal_Profil on 13:50, June 15, 2006) and Derek Ramsey (User:Ram-Man). / GFDL 1.2 (

One explanation for the origin of  the Monarch’s name is that early British settlers in North America were so impressed with the butterfly’s orange color that they named it after King William III, Prince of Orange.

There are actually three species of Monarch butterflies. Danaus plexippus is the species everyone knows in North America. It is also found in Hawaii, Australia, New Zealand, and the Pacific Islands. They are called “Wanderer” butterflies in Australia. The Southern Monarch (Danaus erippus) is found in tropical and sub-tropical South America. Some researchers believe the North American and South American Monarch were once the same species. The third species is the Caribbean’s Jamaican Monarch (Danaus cleophile), which ranges from Jamaica to Hispaniola.

Soon, in early September, only the “Methuselah generation,” the fourth generation to hatch in the eastern population, will migrate south 3,000 miles (more than 4,800 kilometers) to an isolated mountaintop—the oyamel fir forest in the mountains of southwestern Mexico. Amazingly, the butterflies have never been there before! Scientists are still trying to figure out how they find their way. During migration, a Monarch can soar to 11,000 feet (more than 3,300 meters) and spend a lot of time gliding, using warm, thermal air currents the way that hawks do. Many Monarch butterflies arrive at their overwintering sites in Mexico at the beginning of November, when local communities celebrate Dia de los Muertos, the Day of the Dead. According to traditional beliefs, the butterflies are the souls of the ancestors returning for their annual visit.

Many Monarchs from the eastern population overwinter at the Monarch Butterfly Biosphere Reserve. Video by the Florida Museum of Natural History.

How do the butterflies know what path to follow on their migration? Researchers have found that the butterflies have a pair of molecules that are sensitive to the earth’s magnetic field, like a compass. They use these molecules and information from the position of the sun to find their way. You can follow the northward and southward Monarch migrations at Journey North.

I’ve seen Monarch butterflies laying eggs later in the season this year, and I’m not sure why. There are so many factors that can affect the population size and timing of hatches and arrival. Both the eastern Monarch population and the western population (that migrates along the Pacific coast to southern California) have been experiencing serious declines in the last 20 years. There are several reasons for this. Some farmers are using genetically modified crops that are resistant to herbicides, but the herbicides also kill milkweeds growing next to these crops. There is a major decline in milkweed populations due to habitat loss. Cars striking butterflies and habitat loss at overwintering sites are also factors. Climate change might cause Monarchs to migrate farther north, and that might make it harder for future last generations to reach Mexico.

What can you do? Planting a garden for them will help. Monarch larvae (caterpillars) eat native milkweeds (see my post Milkweeds Aren’t Weeds from June 11, 2020 for more on different species). Many nurseries should be having sales and now through fall is a good time to plant. Always ask whether the plants you buy are neonicotinoid free. Neonicotinoids are widely used systemic insecticides that will get into plant leaves and pollen and poison caterpillars, bees, and other insects.

Although larvae eat only milkweeds, adults feed on a variety of nectar plants, including Joe-Pye Weeds (Eutrochium sp.), Blazing Stars (Liatris sp.), Asters (Symphyotrichum sp.), Coneflowers (Echinacea sp.), Goldenrod (Solidago sp.), and more.

Monarch larvae (caterpillars) feed only on milkweeds. Their bright warning coloration helps them let predators know they that they taste bad, but tachinid flies aren’t affected and can lay their eggs on the caterpilars. Photo by USFWSmidwest / Public domain.

Many people raise Monarch caterpillars. Put them in a protected location (pots of milkweeds in mesh containers work well) outdoors rather than in your house. Studies have shown that caterpillars raised indoors fail to migrate properly.

A Monarch pupa eclosing or hatching from a chrysalis is one of nature’s miracles. Video by U.S. Fish and Wildlife Service.

Another way you can help is by tagging migrating Monarchs in the fall. Each tag is a small dot of glue-backed paper with a unique identifying number. You gingerly place the tag on the lower hindwing. Tagged butterflies help researchers learn about migration timing and movement. To order, learn more about how to tag monarchs, and order tags, go to Monarch Watch.

Tagging Monarchs help researchers understand the origins of the butterflies that reach Mexico, the timing and pace of the migration, mortality during the migration, and changes in geographic distribution, Photo

Let’s all help the Monarch by including milkweeds and nectar plants in our gardens or planting pots of them on our apartment stoops and patios. We can work toward creating connecting habitats along Pollinator Pathways.

Nature’s Bug Zappers

At twilight the other day, I was pleased to see a Big Brown Bat flying high among the trees in my yard. I knew that my high-flying friend was doing its bit to keep mosquitoes under control. That’s a good thing, because mosquitoes are vectors for illnesses like encephalitis and West Nile virus—diseases with serious consequences for humans and that will likely become more prevalent as high heat days, urban heat islands, and other consequences of climate change intensify.

A healthy, hibernating Big Brown Bat (Eptesicus fuscus). Photo by Ann Froschauer, USFWS.

Insect elimination devices are not a good substitute for nature’s bug zappers. These devices kill not only mosquitoes, but many beneficial insects. One study of homeowners’ backyards showed that although thousands of insects were killed in a 24-hour period by just one of these devices, only 0.13% were female mosquitoes, which are the ones that seek a blood meal and bite. An estimated 71 to 350 billion beneficial insects are killed annually in the United States by these electrocuting devices. This is likely contributing to the decline of songbirds. 

Not everyone is a fan of bats. Rabies is a concern for some. But research shows that less than 1% of bats carry rabies—so you are more likely to die from a dog attack, bee sting, or lightning strike than from bat-transmitted rabies. Most of us no longer believe the old misconceptions such as bats flying into people’s hair, but somehow the fascinating facts about bats are less well known.

The bat is the only mammal adapted for active flight, with true wings that can fly. A bat can live more than 30 years. Bats can reach speeds of up to 60 miles (97 kilometers) an hour. They use sound to navigate (echolocation) and “see” in the dark. Some species play a key role in pollinating crops. And their ability to control insect populations in our neighborhoods can’t be beat. A single bat can catch 1,200 mosquitoes in an hour. The Mexican Free-tailed Bats (Tadarida brasiliensis) of Austin, Texas, are that city’s most popular visitor attraction.

Wildlife biologists use bio-acoustic equipment to capture high frequency sounds bats emit during echolocation. CT DEEP biologists recently discovered a long lost species, the Eastern Small-footed Bat during bio-acoustic surveys. Click the photo to hear the sounds of a Big Brown Bat. Photo and audio by Wikipedia.

The Big Brown Bat (Eptesicus fuscus), the one I observed in my yard, is one of nine species of bat found in Connecticut. These are the Little Brown Bat (Myotis lucifugus), Eastern Long-eared Bat (Myotis septentrionalis), Eastern Pipistrelle (Pipistrellus subflavus), Silver-haired Bat (Lasionycteris noctivagans), Hoary Bat (Lasiurus cinereus), Red Bat (Lasiurus borealis), Indiana Bat (Myotis sodalis), and the Eastern Small-footed Bat (Myotis leibeii). All are mostly insectivorous, with the exception of the Hoary Bat, which sometimes eats other bats, particularly Eastern Pipistrelles.

The Eastern Small-footed Bat was thought to be extirpated (eliminated) from Connecticut. It hadn’t been seen here since the 1940s, until one was found injured and was rehabilitated in eastern Connecticut in 2016. It had been identified in the area the year before through bio-acoustic surveys, in which wildlife biologists use special equipment to listen to the high-pitched calls bats use to find prey through echolocation.

The Little Brown Bat was Connecticut’s most common species until 2006, when a fungus called Pseudogymnoascus destructans was introduced from Europe, probably on the shoes of visitors to a commercial cave in upstate New York. It spread quickly. This fungus causes White-Nose Syndrome, named for the white fuzz often seen around the muzzles of dead or dying bats. It is a disease that invades and eats away the skin of hibernating bats, including their wings. Because it causes bats to wake up frequently during the winter, they use up their limited fat reserves very rapidly. Bats have been known to fly out of caves in the middle of winter to find food. Some bats survive winter only to die in the spring, when their immune systems kick into overdrive, attacking both the fungal invader and their own tissues. Over 90% of the Connecticut Little Brown Bat population has been wiped out. It is now a state-listed endangered species.

Hibernating Little Brown Bats suffering from White Nose Syndrome. The fungus Pseudogymnoascus destructans gives the disease White Nose Syndrome its name. Photo by New Hampshire Fish and Game.

White-Nose Syndrome has spread across the United States (see the progression map here). There is no known cure yet. Research being done with a naturally occurring bacteria that limits the growth of the fungus needs more testing.

You can help bats where you live.

Build a bat box (a summer place for them to have babies) for your yard or the side of your house to attract these natural bug zappers. Bats are more likely to use these boxes if they are placed on the south side of your house about 20 feet (6 meters) above the ground or on a pole at least 15 feet (about 4.5 meters) high. A location near wetlands, a pond, or lake is even better.

You can help bat populations by erecting a bat house on a pole or the south side of your house. Photo by Mark Buckawicki.

—Report sightings of live and dead bats seen in late December through mid-March to the Connecticut Department of Energy and Environmental Protection Wildlife Division at Also let DEEP know about summer bat colonies that you see. There might be a maternity colony nearby. Report summer colonies to the same address.

—If you have a problem with bats in your attic or other enclosed area, take the humane approach to reclaiming your space. Never pick up a bat that is lying on the ground.

—Tell others about the beautiful side of bats. The more people learn to appreciate this maligned creature, the better for bats—and people. Find more fascinating facts about them from Bat Conservation International.

It’s time to think about all that bats do to help us and how we can help them.