Monarch Roosts

Monarch migration is in full swing.  Some of the migrating butterflies from the Northeast travel as far as 3,000 miles to reach their winter destination in the Sierra Madre Mountains of Mexico.  In addition to finding sources of nectar along their migration pathways to build their fat reserves Monarchs must also seek shelter at night, roosting on land when it cools down and they can no longer fly. 

It appears that roosting is critical for migrating Monarch survival.  Just before dark these solitary diurnal migrants gather in clusters called roosts. A roost can consist of just a few butterflies up to thousands clinging to leaves and branches on a single tree. Cedar, fir, and pine are common species of trees used for roosts, but deciduous trees are also used.

Most roosting trees are along a principal flyway, located in a cool, moist area, provide shelter from the wind and are near a source of nectar. Often roosts last for only a night or two but can last a week or two. Monarchs can but do not necessarily use the same resting sites year after year. It’s generally accepted that these roosts are an anti-predation tactic, employing the strategy of safety in numbers.  To see a map of documented 2021 roosts, go to Journey North’s site:  https://maps.journeynorth.org/map/?map=monarch-roost-fall&year=2021.

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A Win-Win Situation

Bumble bees are nothing if not perseverant.  Prying Bottle Gentian’s (Gentiana andrewsii) petals open is a monumental task, and one that few insects, other than large species of bumble bees, attempt — much less accomplish.  The relationship of bumble bees and Bottle Gentian is an example of a mutualistic association — the bees benefit by having exclusive access to a bountiful and sugary nectar supply as well as pollen, and the plants benefit by attracting “loyal” pollinators that improve the chances for cross pollination.

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Grey Squirrel Bonanza

The diet of the Gray Squirrel is extremely varied — from the cambium beneath tree bark, to tree buds, flowers and seeds, mushrooms, fruits, insects, frogs, bird eggs and much more.  This year there appears to be a bountiful crop of American Beech nuts and Gray Squirrels will likely have a banner reproductive season next spring and summer as a result of it. Consisting of roughly 50% fat and 20% protein, American Beech nuts are one of the most nutritious seeds to be found. (Acorns are only about 9% protein.)

Historically, beechnuts were a popular food source in both Europe and America.  Raw they contain the toxin saponin glycoside, which can cause gastric issues if you eat a large number, but if you’re willing to remove the husks and let the inner nuts dry for several weeks before roasting them, beechnuts can be a tasty delight.  Many recipes – from beechnut pie to muffins and stew – can be found on the Internet.

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Common Green Darners Mating & Laying Eggs

Darners are a family of dragonflies whose members are quite large (some over three inches in length).  Common Green Darners (Anax junius) are one of only two darners in the Northeast with an entirely green thorax (section between head and abdomen).  Often you find them perching low in grasses and weeds.  Males tend to fly along the shorelines of ponds, patrolling for females and keeping other males at bay. 

After mating takes place, the males of some species of dragonflies disappear.  In other species, the male stays nearby, guarding the female and fending off other males that might remove the initial suitor’s sperm and replace it with their own.  Some species go to the extreme of remaining attached to each other while egg-laying takes place.  Common Green Darners are the only species of darner that often lays in this manner – in tandem, with the male still clasping the female while she submerges her abdomen and lays her eggs in aquatic vegetation (pictured).

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Berkeley’s Polypore Fruiting

Polypores are a group of fungi that bear their spores in tubes, or pores, rather than gills. One of the largest mushrooms to fruit on living trees is Berkeley’s Polypore (Bondarzewia berkeleyi), often found on hardwoods, especially on oak trees. Its growth is unusual in both size and form.  When the fruiting body starts to emerge, it resembles a giant hand with short, fat fingers. The tips of the “fingers” expand into huge, flat, fan-like shapes up to ten inches wide that together form an irregular rosette.  The rosette can be more than three feet across and can weigh up to 30 pounds.

You usually find this fungus at the base of trees, but it can fruit from the ground far from any tree if there are roots or the remnants of an old stump beneath the ground, for it is saprophytic (lives on dead or decaying trees) as well as parasitic.

Berkeley’s Polypore is edible when it is young. With age, the fruiting body becomes increasingly tough and has been compared to eating cardboard.  It goes without saying that one should be sure of the identity of any fungus before consuming it.  (Photo of Berkeley’s Polypore & Leo Clifford by Lawrence Clifford.)

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The Surprisingly Varied Diet of Beavers

It is common knowledge that beavers are herbivorous but the extent of their herbivory is not always appreciated.  Examining their skull would tell you that their massive four front incisors (as well as the muscles attached to their jaws) are designed to do some serious chewing.  And serious chewing does take place, especially in the fall. Poplars, birches, alders, willows, maples and many other deciduous trees as well as a few conifers are felled in order to reach and consume the inner bark, or cambium layer. (The de-barked logs and branches are subsequently used to repair dams and lodges). Not only do Beavers need to meet their daily nutritional needs but they must cut enough trees to last them through the winter.

However as spring approaches and they can access land, their diet changes from the woody branches they’ve been eating all winter (from their winter food pile under the water) to a diet that consists mainly of herbaceous plants. Ninety percent of their time is spent eating non-woody plants, often skunk cabbage, water lily rhizomes and grasses in the early spring.  As summer progresses, they seek out aquatic plants, ferns, sedges and a variety of flowering plants. Usually it’s not until late summer/early fall that their incisors are once again given a good workout.

The pictured Beaver had the good fortune of having a large patch of tasty Jewelweed (Impatiens capensis) growing on and adjacent to its lodge.

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The Sexual Strategy of Male Water Striders

Most people are familiar with Water Striders (Gerridae) insects that glide around on top of the water with the aid of water-repellent hairs on their feet that prevent them from breaking through the surface tension of the water. Something most people may not be familiar with is the duress that females are subjected to when it comes to strider reproduction.  

Female Water Striders, who can store sperm from a single mating for weeks, are biologically inclined not to prefer reproduction for a couple of reasons.  For one, after mating, the female has to carry to male around on her back for anywhere from a few minutes to two days, which seriously impairs her ability to forage for food.

Secondly, male Water Striders are the poster boys for sexual coercion, making it all but impossible for a female to reject their advances. With little if any warning, the male mounts a female.  The female now has a choice as to whether to accept his advances. If she chooses to reject them, she doesn’t open the hard genital shield that covers her genital opening. In response, the frustrated male starts strumming the surface of the water which attracts predators such as Backswimmers from below. Because the female is closest to the water, she will be the one who gets injured from any attacks.  Many a genital shield has been opened when the female has been put in this position. (Source: Beaty Biodiversity Museum) Photo: young Water Striders probably produced with the help of sexual coercion; inset-mating Water Striders)

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Black-crowned Night Herons: Not Your Typical Heron

When you think of a heron, you usually think of a diurnal wading bird that has long legs, a long neck and a long bill.  Black-crowned Night Herons don’t possess any of these familial characteristics.  Stocky and relatively short-legged and short-billed, these herons typically rest during the day and start actively hunting at dusk, continuing through the night.

Prey includes fish (half their diet) plus a wide range of other creatures including leeches, earthworms, insects, crayfish, snakes, turtles, small mammals, birds and frogs. The manner in which a Black-crowned Night Heron lures and captures its prey varies.  Two of its most intriguing fishing techniques include bill vibrating (opening and closing its bill rapidly in the water to attract prey) and bait fishing – using bait to attract fish.

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Wavy-lined Emerald Moth Caterpillar: Master of Disguise

Caterpillars are subject to extreme predation, especially by birds.  A single pair of breeding Black-capped Chickadees must find 6,000 to 9,000 caterpillars to rear one clutch of young, according to Doug Tallamy, professor of entomology and wildlife ecology at the University of Delaware. Insects contain more protein than beef and 96% of North American land birds feed them to their young.

It’s thus not surprising that caterpillars have evolved a number of impressive survival strategies, including resembling bird droppings and looking/acting like branches and leaves waving in the breeze.  The Wavy-lined Emerald Moth (Synchlora aeratalarva) larva, or caterpillar, uses camouflage as well, but goes about achieving it in a slightly different way; it attaches bits of the plant tissue (often flowers) on which it is feeding onto its back, so that it blends in to its surroundings very effectively. Totally camouflaged, the caterpillar can munch away in relative safety, replacing dead petals with live ones when necessary.

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Objective: An Empty Nest

Note that the adult Osprey in the air above its nest has no fish clutched in its talons – it is not bringing food back to its young.  Rather, it is doing everything in its power to entice its offspring to take off and catch their own meal. 

An afternoon of observing juvenile Ospreys taking short flights from their nest assured me that the process of fledging had begun.  In the Northeast, young Ospreys usually remain at or near their nest for at least 10 – 20 days after they can fly, during which time their parents continue to bring fish to them.  (This seems quite generous, given that for the past two months both parents (primarily the father) have provided their offspring with food.) Finally, when the young are roughly three months old, the parents go all out to encourage their young to become self-sufficient and secure their own food.

On this particular day, the parents repeatedly soared over their nest and landed in distant trees while the young called out to them over and over. After several of these attempts to lure the juvenile birds away from the nest had failed, one of the parents flew to the nest and proceeded to hover for at least 30 seconds directly above the nest (see photo) before flying towards the nearest body of water. Still, the young birds didn’t budge.  True independence would have to wait at least for one more day.

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