Triplets again—for the third year in a row! I’m not talking about prolific humans, but the Bald Eagle (Haliaeeatus leucocephalus) pair nesting in a giant Cottonwood (Populus deltoides) tree along the Quinnipiac River marsh in Hamden, Connecticut. This nest site is in the Hamden Land Conservation Trust’s Henry and Irene Gargiulo Wildlife Refuge. The three chicks are now flapping and testing their wings in the nest. Any day now, they will fly out to a nearby branch and be taking off by the end of June.
Bald Eagles usually lay two eggs. Successfully raising three chicks is relatively rare for eagles. It is a sign of experienced parents, as well as the clean water with plenty of fish in the Quinnipiac River ecosystem. The expansion of the Clean Water Act in 1972 really made a difference in U.S. waterways.
Eagle nests were not always successful. From the 1950s to the 1980s there were no nesting Bald Eagles in Connecticut. The persistent pesticide DDT had traveled up through the food web and caused endocrine problems in eagles. Eggs had thin shells and eagles were unsuccessful in rearing chicks. The Yale Peabody Museum was among the institutions that documented eggshell thinning through specimens in its collections.
The Bald Eagle was one of the first species put on the U.S. Fish and Wildlife Service’s endangered species list in 1967. DDT was banned in the United States in 1972. Bald Eagles and other raptors slowly began to recover. This recovery has been a real success story. In 2007 the Bald Eagle was removed from the list.
During the 2019 breeding season there were over 316,000 Bald Eagles in the lower 48 states, including more than 71,000 breeding pairs. In 2020, Connecticut Department of Energy and Environmental Protection (DEEP) staff and volunteers recorded 47 successful Bald Eagle nests that hatched 88 chicks, smashing earlier records.
According to Connecticut DEEP Eagle Nest Watch volunteer Mike Horn, the female eagle at the Henry and Irene Gargiulo Wildlife Refuge nest in Hamden laid three eggs. A chick hatched every few days at end of February. Eagles have evolved to lay eggs not all at once, but sequentially, as insurance. If something happens to the first chick there is another to take its place. Although obligate siblicide, in which a larger chick kills its sibling, occurs in some eagle species, it is rare among Bald Eagles. According to Connecticut DEEP biologist Brian Hess, chick mortality is caused by sibling competition when there is a lack of resources and usually not by direct attacks from a larger chick.
The three eggs hatched during the week of April 5, 2021. After a few weeks, it was thought that there were two chicks because the parents were bending over and feeding in different areas of the nest. After about five weeks, the smaller third chick was seen poking its head over the nest rim.
At first the parents will bring fish and break it into smaller pieces to gingerly feed their chicks. As they grow, food is left whole and the young will do the work.
Bald Eagle nests can grow to be huge structures weighing up to a ton (907 kilograms). An eagle pair will add sticks to the nest every nesting season. They don’t remove leftover food and just add sticks and leaves on top. Sometimes pairs will build a new fresh nest nearby.
With so many wildlife species in decline of late, a boom in Bald Eagle populations is a real conservation success story. But it is one where we need to be vigilant in maintaining clean waterways and restricting harmful pesticides. That way, wild Bald Eagles will continue to thrive.
I am always pleasantly surprised, when tromping through the woods, to come upon Pink Lady’s Slipper (Cypripedium acaule) in full flower. I have fond memories exploring the Pitch Pine (Pinus rigida) woods as a boy behind my grandparents’ backyard on Cape Cod. Large stands of Pink Lady’s Slippers grew in the duff under the pines. They are in flower now and I recently found about 20 plants growing in a stand of mature White Pine (Pinus strobus). This species likes the acidic soils under conifer stands.
I was surprised too that these plants had not been gobbled up by the White-tailed Deer (Odocoileus virginianus) that now overpopulate Connecticut’s forests. This must be because the plants were just off a hiking trail used by lots of people who walk their dogs there. The dogs’ marking activities filled the area with a “predator” scent.
Pink Lady’s Slippers are members of the second largest plant family: the Orchidaceae. Although fairly common, Pink Lady’s Slippers are declining in many areas from habitat loss, careless overcollecting, and browsing by deer. Deer eat native plants like these orchids and leave unpalatable non-native, invasive plants. It is not the fault of the deer, but ours. Our grassy yards interspersed among patchy woods have created the perfect edge habitat for deer. Most of Connecticut’s other orchid species are also much more threatened by these factors.
A Pink Lady’s Slipper depends on bumblebees to pollinate it. The bumblebees are attracted by the color of the flower, hoping to find nectar. But it is a trick—there is no nectar. The bees enter a small slit in the labellum, the modified petals that form the “slipper” (which gives rise to its other name, “Moccasin Flower”). Once inside, the bee crawls under an anther that attaches a sticky pollinium, or pollen sac, to the bee’s back. When the bee flies to another Pink Lady’s Slipper to try again, it passes under the stigma, which removes the pollinium and fertilization then takes place. The bee leaves through a small opening in the back of the flower. As in most members of this plant family, the pollinated flower forms a capsule that then dries and splits open, releasing lots of very tiny seeds.
The tiny Pink Lady’s Slipper seeds do not store any food, so they need to interact with a Rhizoctonia fungus in the soil to survive. The fungus gives the seed nutrients for germination and growth. As the plant grows larger, the fungus will in turn get nutrients from the orchid’s roots. This is a symbiotic relationship that has evolved over millennia in which both species benefit.
It is this relationship with fungi and the need for acidic soil that dooms this orchid when people dig up Pink Lady’s Slippers from the wild and try to transplant them to their yards. It is best to enjoy these stunning flowers where they live, take a photo, and leave with a happy memory.
Some birds are always a treat to see, whether they are brilliantly colored or less common. One of my favorites is the Scarlet Tanager (Piranga olivacea). Males are the reverse in coloration from the male Red-winged Blackbird (Agelaius phoeniceus). A male Scarlet Tanager is a deep red all over except for jet-black wings. The female Scarlet Tanager is a yellowish, olive-green with grayish-black wings and tail.
Scarlet Tanagers have recently arrived from spending the winter in the mature, mountain forests of western and northern South America. To see one here, visit a large tract (minimum 70 acres, or about 28 hectares) of mature oak, oak-hickory, or mixed hardwood-hemlock forest in Connecticut. A good way to find a Scarlet Tanager is to listen for its song first and then locate it. It is usually high in the tree canopy. The song is like that of a hoarse American Robin (Turdus migratorius), so it is often called “the robin with the sore throat.” Tanagers also have a very characteristic “chick-burr” note in their call.
A Scarlet Tanager’s diet is mostly made up of insects, including ants, sawflies, dragonflies, cicadas, moths and butterflies, and their larvae. Like its southern cousin the Summer Tanager (Piranga rubra), which is better known for this behavior, the Scarlet Tanager will engage in “bee bashing.” It will hit and rake a bee or wasp against a branch to remove the stinger before eating it. When passing through our area during the spring migration, Scarlet Tanagers can often be found in large oak trees feeding on moth larvae (caterpillars). Oaks host over 400 species of these larvae, making these trees an important keystone species for wildlife.
Scarlet Tanagers will also eat native fruits, including raspberries and blackberries (Rubus spp.), shadbush (Amelanchier spp.), chokeberries (Aronia spp.), and Red Mulberries (Morus rubra).
Nests are usually on a horizontal branch high off the ground, often as high as 50 feet (about 15 meters) or more. Female tanagers lay an average of four light blue eggs. Eggs will hatch in about 10 to 14 days and the young can fly after a few weeks.
For these young birds to successfully fledge they need large tracts of forest. In smaller, fragmented forests these birds are not as successful due in part to nest brood parasitism from the Brown-headed Cowbird (Molothrus ater), which is more common in these edge habitats. Female cowbirds lay their eggs in tanager nests. The female tanager cannot distinguish the cowbird chicks from her own and will try to feed both, but the cowbirds will outcompete the tanager chicks for food. In a study in western New York State, tanager fledgling success was only 22% in patches of woods compared to 64% in an undisturbed hardwood forest.
By helping to protect large tracts of forest and wildlife corridors, you can keep these spectacular birds safe in the future. Plant a native oak tree to give them an important migration “fuel stop.”
Imagine walking in what is now central Connecticut 200 million years ago, when magma rose through cracks in the land as the great supercontinent Pangaea split apart. In the New Haven area, the magma cooled and formed intrusive, or underground, diabase rock. For millions of years the softer sandstones that later were deposited above this rock eroded, leaving the harder, igneous East Rock and West Rock ridges standing as sentinels surrounding Connecticut’s Central Valley today.
These kinds of hills are commonly called traprock ridges, and Connecticut is known for them. Trap is from the Swedish trappa, which means “stairway.” These igneous rocks often cleave off at 90 degree angles, forming walkable steps in many places. The drier microclimates and shallow soils of these ridge tops are unique habitats for flora and fauna.
West Rock Ridge State Park, with its dark basalt rocks, is a heat island for some butterfly species normally found much farther south. One such species that is relatively rare here in Connecticut is the Falcate Orangetip (Anthocharis midea). In the southern part of its range it is found in open, wet woods along streams and rivers and in open swamps. But here, at the northern part of its range, it is confined to traprock ridges. Why the difference? It may need warmer temperatures and these ridges can be warmer than the surrounding valleys. Also, it is ecologically tied to the plants found growing in this habitat.
After mating, Falcate Orangetip females search for plants that are members of the mustard family. They usually deposit only one egg on each plant. At West Rock, females often lay eggs on Lyre-leaved Thale-cress (Arabidopsis lyrata).The larvae (caterpillars) often feed at night on flower buds, flowers, and fruit. They must feed and then develop as pupae before the spring-blooming plants complete their cycle.
Unfortunately, Falcate Orangetip females sometimes lay their eggs on invasive, non-native Garlic Mustard (Alliaria petiolata). The larvae that eclose (hatch) and eat this plant, poisonous to them, die. To protect this butterfly and the other plants it feeds on, it is important to both control Garlic Mustard and preserve traprock ridge habitats.
Falcate Orangetips are sexually dimorphic. Both males and females are white above with a back spot on the upper forewing. Males also have a bright orange patch on the outer forewing. Falcate means “hooked” and refers to the hooked upper forewings. Along with the orange patch on the males, this hook is a way to differentiate this species from the more common, introduced Cabbage White butterfly (Pieris brassicae).
Now is the time to find this springtime butterfly on traprock ridges. Falcate Orangetips are out hilltopping, or patrolling for females. They fly just above the ground and often repeat the same route. If you would like to get out this weekend to see this butterfly, join Larry Gall, Entomology Collections Manager at the Yale Peabody Museum, for a free Connecticut Butterfly Association spring walk at West Rock Ridge State Park in New Haven on Saturday, May 8, 2021. For details and directions visit the CBA website.
On a walk recently I noticed one of the first native shrubs to flower this spring—Spicebush (Lindera benzoin). Its small, yellowish-green flowers really stood out among the sea of bare branches. Spicebush is dioecious, with male flowers on one plant and female flowers on another.
If you find this plant, you can really only identify its sex by looking at the flowers. The inflorescence, or arrangement of the flowers, on the male shrub is a cluster each with a round set of nine stamens. The female shrub’s inflorescence is a cluster of flowers each with a bowling pin-shaped pistil. There aren’t as many female shrubs in the wild as males. The ratio is approximately one female for every ten males.
The pollen and nectar that Spicebush’s flowers provide is very important for early solitary bees and flies. Once pollinated, in late summer and early fall the female flower develops into a bright red fruit called a drupe, a single-seeded fruit with a fleshy covering. These red drupes attract birds like the Wood Thrush (Hylocichla mustelina) and are an important food for birds during their autumn migration. Birds spread these plants when they eat these fruits and excrete the fertilized seeds elsewhere.
The leaves of Spicebush are simple, smooth, and a medium-green color above and lighter green below. A great way to identify this shrub is to look for its alternate-leaved, olive-brown branches with whitish lenticels, or pores. Spicebush grows in rich soils, often near streams and wetlands. If you think you’ve found it, crush the leaves. If it is Spicebush, the leaves will release a sweet, citrusy aroma. This is a great activity for children, because the scent is so dramatic. Try it even in winter by scratching and sniffing the branches. During the Civil War, Spicebush tea was used as a substitute for coffee when rations ran short. Both dried leaves and twigs were steeped in hot water to make a tonic.
Spicebush is one of the few northern members of a mostly tropical plant family, the Lauraceae, or laurels. Members include well-known foods and spices, such as Bay Laurel (Laurus nobilis), cinnamon (Cinamomum spp.), and Avocado (Persea americana).
The only other member of this family in our area is Sassafras (Sassafras albidum). The leaves from this tree also have a spicy scent. Sassafras and Spicebush are the larval food plants for both the Spicebush Swallowtail (Papilio troilus) and the giant Promethea Silkmoth (Callosamia promethea). To find a Spicebush Swallowtail larva (caterpillar), look for leaves that are rolled lengthwise. The caterpillar uses threads to create a tube-like space for itself. You might be surprised to see the large, snake-like false eyes on later stage, or instar, larvae. When threatened, the larva even puts out a foul-smelling osmeterium (an organ used for defense) that looks like a snake’s forked tongue! This insect has certainly evolved some amazing adaptations to keep from being eaten.
You can sometimes find the resting, or pupal, stage of Promethea Silkmoths, which look like dead leaves, hanging from Spicebush branches in the winter.
With its early spring flowers, attractive foliage and fruits, and important connections to wildlife, Spicebush makes for a great native shrub for your yard. Plant one and help early bees, butterflies, and silk moths.
Last summer I pulled up a bunch of Garlic Mustard (Alliaria petiolata) that has invaded the edges of my property with a vengeance. It is rather easy to pull the entire plant, roots and all. But what I didn’t realize was that I was also pulling up its 50-year seed bank and that one plant was probably replaced by 50 or more seedlings. As in the Greek myth, I felt like Sisyphus fruitlessly pushing the rock up the hill. This year I am going to put wet cardboard down over the plants, followed by a four- to six-inch layer of old wood chips. Non-native invasives like these can take over habitats from native plants. And they aren’t eaten by insects, so fail to provide the roles in ecosystems that native plants do.
I am determined, however, to get back at those plants in another way—by eating them! Garlic Mustard is a biennial, having a two-year growth cycle. It has a basal rosette of small green leaves its first year and is evergreen through the winter. The second year it grows larger, sends up a stalk with white flowers, and, after releasing thousands of seeds, it dies.
According to experts that forage for wild plants, the second-year roots taste like horseradish. You can also eat the second year leaves. Gather the leaves (plants growing in the shade are usually less bitter), blanch them in water, and mix with olive oil and cheese in a blender to make a pesto. There are also many Garlic Mustard recipes online.
A word of caution: Garlic Mustard contains traces of cyanide, which is one way the plant defends itself from predators. Many members of the mustard family—such as broccoli, cabbage, and kale—also contain traces of this toxin. To be on the safe side, limit wild mustard collecting to once or twice a month. Cyanide is also water soluble, so blanching or boiling the leaves before consumption measurably reduces cyanide levels.
Now is also the time to gather one of the most destructive invasive plants out in the wild: Japanese Knotweed (Fallopia japonica). For the next few weeks, until about mid-May, the new reddish, asparagus-like shoots of this plant are yours for the taking, and you don’t have to worry about overharvesting! Actually, when picked, smaller shoots will arise again and can be gathered later. They taste a lot like rhubarb, tart and crunchy, and can be used as a substitute in apple–rhubarb crisp or strawberry–rhubarb pie.
Wild Garlic, also called Lawn Garlic or Onion Grass (Allium vineale), is an introduced plant from Europe, northwestern Africa, and the Middle East. It can be found growing in many lawns. This plant makes a great substitute for Ramp or Wild Leek (Allium tricoccum), a native plant that has been overharvested and is now vulnerable in many areas. Wild Garlic can be dug up and the small bulbs used as a flavoring in soups. The slender leaves can be sliced up and used just like chives. Some natural food markets are selling it for $3.00 per bunch!
Another plant on the top 10 invasive nasties list is Mugwort (Artemisia vulgaris). I am constantly pulling this plant to try to get rid of it. But doing that can be futile, as it has underground stems (rhizomes). If any tiny piece is missed, a new plant will grow. Author and wild food forager Tama Matsuoka Wong says the feathery leaves are “awesome as tempera.” Martha Stewart has a Mugwort soup recipe.
Before you harvest any of these invasives, make sure you know the history of the soil where the plant is growing. Roadsides, parking lots, and other potentially contaminated ground may have high levels of lead and other pollutants. Also, be sure you can identify the plant properly and not be confused by look-alike plants that could be toxic. Go out with an expert forager if you are unsure.
Meet expert foragers Gina Rae La Cerva and Alexis Nicole Nelson through the Yale Peabody Museum at the free webinar “Feasting Wild: A Conversation on the Politics, Pleasures, and (Bio)diversity of Foraging” on Thursday, April 29, 2021 at 5:30 pm. Register here. Happy foraging!
Soon waves of migrating neotropical birds will pass through our area. They will be feeding furiously on hatching insects in the tree tops this May, but some have already arrived and have been here for weeks.
Eastern Phoebes (Sayornis phoebe) flew in from the southern United States and from as far south as Mexico, where about a third of these flycatchers spend the winter. Some Pine Warblers (Setophaga pinus) are permanent residents in Florida, Georgia, and the Carolinas. Many winter as far south as eastern Mexico and the Caribbean and migrate north in the spring. One of the most common wintering neotropical migrants where I sometimes vacation in southwest Florida is the Palm Warbler (Setophaga palmarum), a species that also winters in the Deep South and the Caribbean Islands.
Why do these insect-eating birds arrive so early? Eastern Phoebes come here as early as March, occasionally even when ponds are not free of ice. Pine and Palm Warblers arrive a few weeks later. It may be that arriving early is an advantage for these species that lets them claim open nesting territories. But this sometimes comes with a price. Late winter and early spring snowstorms could prevent them from finding food.
The large, explosive spring hatches of flying insects and moth larvae haven’t happened yet, so what are these birds feeding on? Most of the Eastern Phoebe’s diet is made up of flying insects, but they also eat spiders, ticks, and millipedes, and occasionally small fruits and seeds. Pine Warblers poke through bark, needles, and pine cones looking for dormant insects and early arriving birds are often seen searching through leaf litter for insects and other arthropods. They will also eat seeds and berries. Although Palm Warblers glean insects off tree bark and jump up for flying insects, they habitually feed on the ground and can even be spotted foraging there with sparrows. They will also eat bayberry (Morella pennsylvanica) and hawthorne (Crataegus spp.) fruits. So, an advantage these early migrants have is that they are adapted to finding food on the ground and eating fruits and seeds.
The Eastern Phoebe and Pine Warbler both nest in Connecticut, but the Palm Warbler is just passing through. It nests farther north usually on the ground in tamarack (Larix spp.) bogs of the boreal forest.
The Eastern Phoebe can be identified by its slate gray back and relatively large, dark head. It also wags its tail up and down. This bird gets its name from the song of the male: a raspy “fee-bee”.
The Palm Warbler also pumps its tail up and down. Both these birds and phoebes are among the few species that do this. The adult has a gray back, rusty coloring on the crown (top of the head), and rufous-colored streaks on its yellow belly. Its song, a weak, buzzy trill, is not frequently heard.
The Pine Warbler also has a yellowish belly, but its wings are gray with white wingbars and it has a yellow ring around its eyes. There are indistinct olive streaks on the sides of its breast. The male’s song is a long, liquidy trill.
Before migrating, these birds build fat reserves up to 50% of their body weight. Once these reserves are used during migration, the birds need to stop and refuel. Dave Ewert, senior conservation scientist with the American Bird Conservancy, describes three kinds of habitat that migrant birds look for.
“Fire escapes” are used in times of stress when birds are exhausted, starving, or disoriented. Under such emergency conditions, they stop at any habitat they can find. Small patches in urban and industrial areas can be fire escapes for migrants.
“Convenience stores” offer more abundant and higher-quality food and shelter, and are larger than fire escapes. Birds prefer them over fire escapes if they have a choice. Suitable habitats in parks, suburban gardens, and isolated rural woodlots are important convenience stores for migrants.
“Full-service hotels” are sites with the best habitat—plenty of nutritious food for refueling, safety from predators, and adequate shelter from inclement weather. These sites are natural areas, undeveloped rural lands, parks, and relatively large wildlife refuges.
Whether you live near a fire escape, a convenience store, or a full-service hotel, plant native perennials, shrubs, and trees that attract insects. Think of your yard or nearby park as a thing of beauty, not only because these plants are attractive to us, but because they are important refueling stops for these colorful birds.
I look forward each year to looking along streams to find one of my favorite spring wildflowers soon to be in bloom—Marsh Marigold (Caltha palustris). But it has an exotic cousin, a look-alike that threatens its existence and that of other native spring ephemerals such as Trout Lily (Erythronium americanum) and Spring Beauty (Claytoniavirginica). It is Lesser Celandine (Ficaria verna).
Both Marsh Marigold and Lesser Celandine (also called Fig Buttercup, Pilewort, and Fig-crowfoot) are in the buttercup family, Ranunculaceae. They both have heart- or kidney-shaped leaves and yellow flowers.
So how do you tell them apart? Lesser Celandine’s leaves emerge really early in the spring, as early as February, and they are out now. When you are driving or hiking, look around to see what plants are in leaf. Many non-native invasives like Japanese Barberry (Berberisthunbergii) and Garlic Mustard (Alliaria petiolata) will leaf out before native plants, thereby outcompeting them for light. Check out stream and river banks and pond edges. Marsh Marigold is usually near the water’s edge. Lesser Celandine is more adaptable and can also be found in rich soils farther from water, even in sunny yards.
Lesser Celandine is a slightly smaller plant and flowers earlier than Marsh Marigold, usually in March or April here in Connecticut. If you see flowers on plants in late April to June, you can be almost certain it is Marsh Marigold. Marsh Marigold has 5 to 7 yellow tepals (undifferentiated petals or sepals), whereas Lesser Celandine has 7 to 11 yellow petals and 3 green sepals below the petals.
Invasive Lesser Celandine can form huge, extensive mats if left unchecked. The U.S. Department of Agriculture has predicted that it could establish itself in 79% of the continental United States. Now that’s an adaptable plant! It can do this because it forms tubers, which break off very easily through ground disturbance and flooding. After flowering, Lesser Celandine also forms bulbils in its leaf axils. This vegetative little bulb is a clone and can become a new plant.
How do you control this plant? If you have a small patch, try to eliminate it before it spreads into a monoculture. Control small patches by hand-digging the plant, making sure to sift out all tubers and throwing them in the trash. The tubers and roots are in the first 3 inches (about 8 centimeters) of the soil. Larger incursions are more difficult to control.
Marsh Marigold’s deep yellow flowers, larger than those of Lesser Celandine, are very striking near water. If you have a damp place in your yard in part to full sun, try growing it. It is sold at nurseries, particularly for plantings next to water or in rain gardens. Be sure to ask that the plants sold are nursery propagated.
Native plants like Marsh Marigold have spent thousands of years co-evolving with the pollinators in their ecosystem. Insects are co-evolved to feed on its leaves or gather its pollen and nectar. They in turn are fed on by birds. The nectar and pollen of the flowers of Marsh Marigold attract flies and bees, including the Giant Bee Fly (Bombylius major), syrphid flies, and halictid bees.
Yet, in a few decades, Marsh Marigold can be undone by non-native thugs like Lesser Celandine. By knowing the difference between the two and giving the native a chance to compete we can control the invasive and ensure a healthy ecosystem, even on a small scale like our own backyard or nearby streams.
Last fall I planted snowdrops (Galanthus spp.) and crocus (Crocus spp.) to have very early blooms available for the first pollinators that hatch in the spring. Even though these are not native, they do provide early nectar and pollen sources for native solitary bees. This would be before native plants such as Pussy Willow (Salix discolor) and Spicebush (Lindera benzoin), as well as spring ephemerals like Bloodroot (Sanguinaria canadensis) and Dutchman’s Breeches (Dicentra cucullaria), begin to flower. I am trying to gradually lose the lawn and to plant at least 70% native plants, as recommended by entomologist Douglas Tallamy in his book Bringing Nature Home (Timber Press, 2007).
Those spring bulbs I planted are in full flower now. I count at least three different species of bees hovering around them. There is one standout in full force: a mason bee (Osmia spp.). Many of the species in this genus are polylectic, meaning they gather nectar and pollen from the flowers of different plant species. However, there are a few specialist mason bees that only like certain flowers. The Beardtongue Mason Bee (Osmia distincta) only visits the flowers of beardtongues (Penstemon spp.), whereas Osmia virga frequents blueberries (Vaccinium spp.).
There are about 20 species of mason bees in Connecticut. One of the most common is the Blue Orchard Bee (Osmia lignaria). Like many native bee species, however, it seems to be on the decline. Researchers from the Connecticut Agricultural Experiment Station have noticed that two non-native mason bees, the Japanese Horned-face Bee (Osmia cornifrons) and the Taurus Mason Bee (Osmia taurus), are displacing the Blue Orchard Bee. The Japanese Horned-face Bee was released in the Northeast to pollinate orchards. The Taurus Mason Bee, a very similar species, showed up soon after.
Scientists studying mason bees in the U.S. Mid-Atlantic states used pan traps to find out how common the two exotic and six native Osmia species have been over the span of 15 years, from 2003 to 2017. All the native species showed substantial annual declines ranging from 76% to 91% since 2003. The two exotic species fared much better—O. cornifrons was stable and O. taurus increased 800% since 2003. Scientists think these exotic species are outcompeting native species for nest sites and food sources. They may have also introduced parasites to native species.
Unlike Eastern Carpenter Bees (Xylocopavirginica), which as you probably know drill holes in wood, mason bees depend instead on holes and tunnels made by other insects and by birds. About 30% of our native bees are tunnel nesters.
Mason bees are a little smaller than honeybees. They are not aggressive. The male doesn’t sting and the female will only sting if handled roughly. Adult females collect pollen and nectar to feed their young. A female will pack this pollen and nectar into “bee bread,” deposit it into a chamber, and lay an egg next to it. There are five to eight of these brood cells in each tunnel. She lays an unfertilized egg, which will be a male bee, at the end of the chamber closest to the outside. When the eggs hatch, the larvae feed on the pollen and nectar stored in the nest. After 10 days, each spins a cocoon and becomes a pupa in its cell. By the end of summer the bees transform into adults, a stage called an imago, but remain in their cocoons throughout the winter.
Males hatch first in the spring. They wait outside the tunnels and mate with females when they hatch. Mating is their sole purpose. Female mason bees live about one month, males much less.
Mason bees are incredibly effective pollinators. Unlike honeybees, which aren’t up and about early in the morning, mason bees are out both early and late. Apple farmers know how efficient and effective these pollinators are and have created bee boxes for them. You can too and now is the time to put them up. Like bird boxes, bee boxes are mostly for your enjoyment. They are not a necessity for the bees, since they can find tunnels in the wild.
You can make your own mason bee box by drilling holes in a block of wood. The holes should be between a quarter inch (6 mm) and three-eighths inch (9.5 mm) in diameter and 6 inches (15 cm) deep. Keep the holes closed at one end. You can also buy a mason bee nest box at specialty stores like the Fat Robin Wild Bird and Nature Shop in Hamden, Connecticut. Another way to create your own box is by cutting off the lower stems of invasive Phragmites grass (Phragmites australis), tie them in a bundle, and plug the hole on one side with plastic wood filler or something similar.
The best location for a bee nest box is in a dry, protected place with an eastern or southeastern exposure. In the fall you can use a paper straw liner, inserted into each hole, to retrieve the cocoons to “wash” your bees. This will get rid of most of their mites and diseases. Clean the cocoons between October and December, because the adults are fully formed by then.
First, soak the cocoons in cool water to soften and remove mud. Be sure to use water no warmer than 50 °F (10 °C), so you don’t “wake up” the bees. Using a sieve, gently roll and move cocoons through the water. Discard any debris. Next, soak the cocoons, for no more than 10 minutes, in cool water with a 0.05% bleach solution (1 tablespoon bleach per 1 gallon water, or 15 milliliters of bleach in 3.75 liters of water) to kill bacteria, fungi, and most mites. Rinse well under cool water to remove all traces of bleach. Dry on a clean paper towel for one hour. Sort and discard damaged, diseased, or parasitized cocoons. Put the cleaned, air-dried cocoons in a small container with air holes and store this in your refrigerator for the winter. When you see bees flying around your garden in the spring, open the box outside in a sheltered location. See the comprehensive, free online book called How to Manage the Blue Orchard Bee by Jordi Bosch and William P. Kemp (Sustainable Agriculture Network, 2001) for more information.
Many of our pollinators are undergoing population declines. You can help mason bees by providing native trees, shrubs, and perennials in your yard. Try to have a variety of plants in bloom from early to mid-spring, when the bees are active. Other plants these bees will also visit are Redbud (Cercis canadensis), oaks (Quercus spp.), Black Willow (Salix nigra), Beach Plum (Prunus maritima), and shadbush (Amelanchier spp.), and many more. If you have to cut down a tree, consider leaving 10 to 20 feet (3 to 6 meters) of the trunk that can become nesting sites and tunnels for mason bees. We can all do our part.
During the brief interlude of spring-like weather we had recently, even with patches of snow still on the ground, I spotted a butterfly flitting through the forest. It was a Mourning Cloak (Nymphalis antiopa), named long ago for its dark-brownish black wings colored like the cloak of a person in mourning.
How could this butterfly have gone through its life cycle—from egg to larva (caterpillar) to chrysalis to adult—in this cold weather? Well, it didn’t. The Mourning Cloak is one of the few butterflies that overwinters as an adult, taking shelter under bark or in a tree cavity.
How do they survive the cold? They go into diapause, a dormancy many insects undergo in which their systems shut down and their bodies produce glycerol, a kind of antifreeze that protects their vital organs from freezing. Most insects overwinter as eggs, as larvae or as pupae (the resting stage known as a chrysalis in butterflies and as a cocoon in moths).
Mourning Cloaks live long compared to most butterflies—up to 12 months. That they overwinter might be one reason. When the adults emerge in late winter or early spring, they will warm up in sunny patches. They also turn their bodies to the sunlight to absorb heat.
These butterflies emerge when few flowers are in bloom. Flowing tree sap, with sugars and proteins, are an important early food source for Mourning Cloaks. Later they feed on ripe and fallen fruits as well as the sugary exudate from aphids. They don’t seek nectar as much as many other butterfly species, but I have seen them nectaring on the catkins of Pussy Willow (Salix discolor) and Black Willow (Salix nigra). This is yet another reason to include native shrubs and trees such as these in your landscape. Native willows are an important early pollen source for many native bee species too.
Mourning Cloak males will look for an appropriate territory, a prime location to attract a female. On mating, the female will lay her eggs on leaves of larval host plants: willows, American Elm (Ulmus americana), Hackberry (Celtis occidentalis), ashes (Fraxinus spp.), poplars (Populus spp.), and birches (Betula spp.). They hatch about 12 days later. In early stages the larvae group together in a web, perhaps an adaptation for protection against predators. The caterpillars are black with spines and rows of red dots running down the center of the back, which might be aposematic, a warning coloration. If handled, those spines can sting.
After undergoing five instars (larval growth stages and sheds), the Mourning Cloak spends about two weeks as a chrysalis, before eclosing, or emerging as a butterfly in mid-summer. Adults who lived through the previous winter then die. This new brood is the future of the species.
How can you help this butterfly and other important insects to live long in your yard? Try to garden naturally without using pesticides. Don’t use butterfly boxes. They really don’t work and actually attract hornets, which can prey on butterflies. Allow a “messy” section in your yard, with bark and leaves for overwintering sites. Plant native trees and shrubs such as those mentioned here. We all can do our part to help this striking butterfly and many other important species to prosper.