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Archive for June, 2014

Common Loons: Nest-building

6-30-14  Loons #1 - nest building 496Naturally Curious posts for the next four days will be devoted to Common Loons. They are nesting now, eggs are hatching, chicks are swimming, parents are feeding – life is good on ponds and lakes in the north woods, and I would love to share this magical time with you.

Both members of a pair of Common Loons contribute to nest-building in May or June. Their ground nest is often built on the sheltered side of an island, facing the mainland. It is usually within just a few feet of the water, eliminating the necessity for the loons to walk very far. (The position of their legs far back on their bodies is advantageous when it comes to diving and swimming, but makes walking very challenging.) Both male and female share the building of the nest, throwing submerged vegetation from the water onto the nest site or pulling it from the water while sitting on the nest. Material continues to be added to the nest throughout incubation. Nearly two feet in diameter, a nest can take a week or so to build. Successful nests (those that produce chicks) are often re-used from year to year.

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Ovenbirds Nesting

6-27-14 ovenbird nest2  071Ovenbirds, the warblers responsible for the “teacher–teacher-teacher- TEACHER” song that reverberates throughout deciduous woods at this time of year, are known not only for their distinctive song, but also for their unique domed, ground nests (see dead center of photo). It is the resemblance of their nest to an old-fashioned domed oven that is the source of the Ovenbird’s common name. The materials used to build the nest (bulk of nest is made up of leaves, with additional bits of plant stems, bark, pine needles, rootlets , moss and a lining of deer and/or horse hair), as well as the roofed structure make it all but invisible to most passersby. More often than not the female Ovenbird chooses a site with an especially thick leaf layer on which to build her 6 ½-inch-diameter nest. She enters and exits through a side entrance that is roughly 2 inches wide. The female incubates and broods the young, but both parents feed them, approaching and leaving the nest on foot along a few partially concealed routes. As the nestlings grow, the top of the nest is frequently pushed back, exposing the nest cup. No attempt is made by either parent to reconstruct the roof before the young fledge in about a week to ten days. (Thanks to Tii McLane for photo op.)

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Gray Treefrogs Calling

gray treefrog 021At this time of year, bird-like trills are often heard in wetlands, where male gray treefrogs (Hyla versicolor) are calling to potential mates. The chorus ramps up at night, but the songsters can be hard to find during the day, when they often hide in tree cavities or high up in the canopy. (Their large toe pads produce mucous which allows them to adhere to smooth bark.) The colors of a gray treefrog vary with the colors of its background and environmental factors such as season and humidity, but shades of gray are most common, with black blotches on the back. Variations of brown, green, and pearl-gray colors have been noted, with green being more prominent during the breeding season. Warm, humid weather seems to elicit calls from these well-camouflaged amphibians. To watch and hear a calling gray treefrog, go to http://www.youtube.com/watch?v=2kd5c4p8-0M. (Thanks to Rachael Cohen for photo op.)

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Caterpillars Molting

6-25-14 caterpillar molting 044A caterpillar is the larval stage of a moth or butterfly. It is the only stage that has chewing mouthparts, and therefore a caterpillar spends most of its waking hours eating. This consumption of food results in massive growth, making its skin/exoskeleton very tight. When this happens, a hormone called ecdysone is produced, prompting the caterpillar to molt, losing its old exoskeleton (to left of caterpillar in photo) under which is a new and larger exoskeleton. After the molt, while the new exoskeleton is still soft, the caterpillar swallows a lot of air, which expands its body. Then, when the exoskeleton hardens, it lets the air out and has room for growth. Caterpillars molt four or five times as they grow. Each different caterpillar stage is called an instar. (Photo: Forest Tent Caterpillar)

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Cedar Waxwings Conserving Energy

cedar waxwing at oriole nest 241Your eyes are not fooling you. A Cedar Waxwing is visiting a Baltimore Oriole nest. Why? If you had the choice between scouting the landscape for an odd board here and there with which to build your house, or going to a deteriorating, abandoned house and helping yourself to a goldmine of available lumber, which would you choose? The oriole nestlings have fledged — their nest has served its purpose. It’s highly unlikely that the parents would ever use the nest again. Waxwings, which are relatively late nesters, discovered the abandoned nest and are taking advantage of the oriole’s (female builds nest) hours of collecting raw materials. Fiber by fiber a pair of Cedar Waxwings pulled this nest apart and recycled what they removed.

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Showy Lady’s Slippers Flowering

6-23-14 showy lady's slipper 139As with Pink and Yellow Lady’s Slippers, one of Showy Lady’s Slipper’s three petals is greatly modified into a large inflated pouch called the labellum. The two other petals attract pollinators with an alluring odor, but the insects that enter into this pouch are in for a disappointment, as lady’s slippers produce little or no nectar. Once inside, visiting insects are guided by very fine, slanting hairs on the inner surface of the pouch towards the flower’s pistil and stamens. Once it has entered the constricted passageway that leads to the reproductive parts, an insect cannot turn around and must pass by the pistil and stamens. Lady’s slippers rarely self-pollinate, so it is crucial that they not only attract, but also extract pollen from insects to achieve cross-pollination. Thanks to their structure, this happens more often than not. The flowering of Showy Lady’s Slippers peaks in Mid-June in central Vermont; if you know of a nearby fen (peat wetland that gets its water from rainfall and surface water), best visit it soon, as that’s where you’re most likely to find this species of orchid.

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Sexing a Painted Turtle

painted turtle 035If you see a Painted Turtle on land at this time of year, chances are great that it’s a female on her way to or from laying her eggs. But how do you know the sex of a Painted Turtle at any other time of year? It helps to have both sexes in front of you, as it’s all relative, but in general, males have much longer nails on their front feet than females (good for gripping females during mating). Males also have longer and thicker tails. The cloaca (passageway into which the intestinal, urinary, and genital tracts open) of a male Painted Turtle is close to the tip of the tail, whereas the female’s cloaca is near the base of the tail. A super large Painted Turtle (8”-10”) is more likely to be a female, as their shells can grow to a larger dimension than those of males. (photo: female Painted Turtle)

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Avian Parental Care

yellow warbler nesting pair 078Parental care varies according to species, but usually only one sex is responsible for the care of offspring. The exception to this rule is birds, where at least 81% of species exhibit bi-parental care. It may not be shared equally, but both contribute in some way. Fairly typical are Yellow Warblers (pictured). The female Yellow Warbler builds the nest, lays the eggs, incubates the eggs, and broods the young all by herself. The male occasionally feeds his mate while she’s on the nest and when the eggs hatch, shares the delivery of food to the nestlings and the cleaning of the nest. Recent research has shown that the amount of parental care provided by males is directly related to the genetic fidelity of the female. If she’s true blue, then she may well receive a lot more help from her mate.

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Scarab Beetle Antennae

6-16-14  scarab beetle antennae 261Beetles in the family Scarabaeidae share several characteristics, including specialized antennae. The last three to seven segments of each antenna form flat plates, or lamellae, that can be expanded like a fan (see Japanese Beetle insert) or folded together into a club (see June Beetle photo). When these plates are separated they are being used as sensory devices to detect odors. When folded together, the antennae are used as clubs by some species of fighting male scarabs. The next time you see a June Beetle, Rose Chafer or Japanese Beetle, take a second to inspect its antennae before parting company.

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Fern Balls

fern ball 216At this time of year, many new sterile fern fronds have “fern balls” at their tips – something has taken the last few inches of the tip of the frond and stitched it together into a ball-shaped shelter bound with silk. If you open one of these balls, you may find frass – droppings from the immature insect that was dwelling within the ball while consuming the terminal leaflets of the fern. Sometimes, but not always, you’ll find the larva responsible for the frass. Many species of ferns, as well as other plants, are host to many species of larvae, and many of these larvae are immature moths. Pictured is Christmas Fern, Polystichum acrostichoides, which is likely the host of the larva of Herpetograma sphingealis, the Serpentine Webworm Moth, or its close relative, H. aeglealis. Larvae live in these shelters for about a month before pupating and emerging as small, brown moths.

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Eastern and Canadian Tiger Swallowtails

6-16-14 Canadian Tiger SwallowtailSwallowtails are North America’s largest butterflies, and their tropical relatives are the largest butterflies in the world. At this time of year, Tiger Swallowtails emerge from their chrysalises and seek nectar wherever they can find it, often in gardens. The two common species in the Northeast are the Eastern Tiger Swallowtail and the Canadian Tiger Swallowtail. Those of us living in northern New England are most apt to see the Canadian Tiger Swallowtail, which replaces the Easter Tiger Swallowtail this far north. Both species can be found further south. There are ways to tell these two swallowtails apart (although sometimes where their ranges meet, it can be difficult). The Canadian Tiger Swallowtail is smaller than the Eastern Tiger Swallowtail, but unless you have them side-by-side, this isn’t all that helpful. The easiest way to tell the two species apart is to look on the underside of the butterfly’s forewing and see if the yellow band along the margin is solid (Canadian Tiger Swallowtail, Papilio canadensis), or if it is broken up into spots (Eastern Tiger Swallowtail, Papilio glaucus). (Photo is of a Canadian Tiger Swallowtail)

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Baltimore Orioles Building Nests

6-13-14  b.oriole nestOnce the female Baltimore Oriole has selected her mate, she chooses a nesting site within his territory, often the tip of a slender outer tree branch, as it’s relatively inaccessible to predators. The female usually builds the nest by herself, taking 4 – 15 days to complete it. The first few fibers are wrapped loosely around branches. With apparently random poking, knots and tangles are created in these fibers. The female than adds more fibers, one at a time, to extend, close and line the nest. Somewhat miraculously, after days of laborious work, the nest takes on its gourd-like shape. Initially the weaving of fibers from plants such as grasses, milkweed stems or grapevine bark can be observed (horse hair, twine and synthetic fibers are also used). Towards the end, when the nest lining is added, the bird is hidden inside the nest and all that’s visible is the periodic bulging of the nest where she is applying softer material (often cottonwood or willow seed fluff, milkweed seed plumes or feathers) to cushion her eggs and nestlings.

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Pine Pollen: Nature’s Testosterone

6-12-14 pine pollen  100If you’ve noticed yellow clouds near pine trees recently, or a layer of yellow “dust” on your car or pond, you’ve witnessed the annual dispersal of pollen by male pine cones. Light and fluffy so as to be easily distributed by the wind (rather than insects), these minute pollen grains containing sperm cells can be found just about anywhere this time of year, including the nostrils of humans. All pines have separate male and female (seed) cones on the same tree. Male pine cones, which produce pollen, are much smaller, occur in clusters, are more papery, and remain on the tree for a much shorter period of time than most female pine cones. (By July they will litter the ground beneath pines before they quickly disintegrate.) Although it may mean a brief period of sneezing has to be endured by those allergic to it, this “golden smoke” not only creates beautifully intricate patterns for us to enjoy and makes it possible for pine trees to make the next generation of seeds, but it is also touted as an agent of increased testosterone and strong sexual libido, anti-aging, skin rejuvenation and improved immune systems for humans. Haste ye to a natural food store (or the closest pond!). (photo – Red Pine pollen & male cones)

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Wolf Spider Eggs Hatching

6-10-14 wolf spider & egg sac & babies IMG_7251Female wolf spiders provide both their eggs and young with a considerable amount of maternal care. They actually carry their egg sac around with them, attached to the spinnerets at the end of their abdomen, as they hunt for food and go about their lives. Careful to keep her egg sac from touching the ground, the mother makes sure it receives a sufficient amount of sunlight each day, presumably to enhance incubation. She also mends any tears that appear in the sac. The eggs hatch in one to two weeks, and 4 to 22 days later, the mother perforates the egg sac either part way or all the way around the seam by rotating the sac with her legs as she makes tiny holes in it with her chelicerae (mouthparts). Within three hours of this, spiderlings crawl out of the sac through the holes made by the mother, climb up onto her abdomen (see photo), and remain there for days or weeks, depending on the species.

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Hummingbirds Extracting Nectar

6-10-14 hummingbird tongue 045For years scientists assumed that hummingbirds passively extracted nectar from flowers with their tongue through capillary action, but it turns out that this is not the case. A hummingbird’s forked tongue (which is twice as long as its beak) is lined with hair-like extensions or fringes called lamellae. When it is inserted into a flower and immersed in fluid, the tongue separates and the lamellae extend outwards so that open grooves (between the lamellae) lay flat. As the hummingbird pulls its tongue into its mouth, the forked tips come together and the lamellae roll inward, trapping the nectar within the tongue until it is swallowed by the hummingbird. No output of energy is necessary on the part of the bird – this process is automatic, takes all of 1/20th of a second, and occurs thousands of times a day. (Thanks to Ginny Barlow for Ruby-throated Hummingbird photo op.)

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Rosy Maple Moths Emerging

6-9-14 rosy maple moth 161This is the time of year when moths rule the nights. Many moths in the silkmoth family, Saturniidae, emerge in June, including giant silkmoths such as Luna Moths and Cecropia Moths. A smaller member of this family also appears at this time of year. While the 1 to 2-inch Rosy Maple Moth (Dryocampa rubicunda) wingspan doesn’t come close to many of the giant silkmoths’ 5 to 6-inch wingspan, its pink and white or yellow coloring is stunning. Adults emerge mid-May through mid-July in the late afternoon, and they mate in the late evening. Females begin laying eggs at dusk the next day in groups of 10-30 on leaves of the host plants (Red, Sugar and Silver Maples, as well as Box-elder and some oak trees). The eggs hatch in about 2 weeks and the larvae are referred to as Green-striped Mapleworms. They occasionally do considerable damage to their host trees when their population soars. In New England there is only one brood per summer, with the larvae pupating and overwintering underground.

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Dragonfly Eclosure: A Vulnerable Time

newt eating dragonfly2 021Dragonfly larvae reside in ponds until the time comes for them to climb up stalks of emergent vegetation or adjacent rocks, split their larval skin and emerge as adults (a process called eclosure). Before it can take flight, a dragonfly has to cling to the substrate long enough to expand its wings by pumping fluid into them, and dry its exoskeleton as well as its wings. During this time the dragonfly is extremely vulnerable – not only can it not fly, but it is usually situated directly above the water. The slightest breeze can blow it from its precarious perch into the water below, where opportunistic predators such as this Eastern Newt are at the ready and make quick work of their helpless prey.

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Crab Spider Guarding Egg Sac, not Jumping Spider!

6-5-14 jumping spider2  077Thanks to the sharp eye of Peter Hollinger, a Naturally Curious reader, the spider in this photograph can correctly be identified as a crab spider, possibly in the genus Xysticus, not a jumping spider! The eyes of this crab spider, while impressive, are not nearly as much so as a jumping spider’s. In addition, this crab spider’s four front legs are relatively longer than those of a jumping spider’s. Neither of these types of spiders spins a web to capture prey and both stay with their egg sacs to guard them. Thank you, Peter!


Jumping Spider Guards Egg Sac

6-5-14 jumping spider2  077Spiders protect their eggs by wrapping them up in a sac they make out of silk. Some species (such as garden, or black-and-yellow argiope, spiders) then die, leaving their egg sac to withstand the elements, as well as potential parasites and predators, on their own. As you would guess, these sacs are usually fairly impenetrable. In other species, female spiders survive long enough to guard their eggs until they hatch, or even until the young spiderlings disperse, and these sacs are usually far less tough. In the species where the female protects her eggs, some females carry their egg sacs with them at all times (wolf spiders, nursery web spiders) while others (jumping spiders) simply remain with the sac. Their excellent eyesight and impressive ability to leap many times their body length gives jumping spiders an advantage over any potential predators. (Photo – jumping spider with egg sac)

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Warbling Vireo Warbles on Nest

6-4-14 warbling vireo on nest 226 As a rule, male birds do not sing near their nest. When they approach their nest, whether to take their turn incubating eggs, brooding nestlings or delivering food, they are apt to be silent, or sing much more softly than usual, so as to avoid bringing attention to the nest. There are exceptions to this rule, however – male Chipping Sparrows, House Wrens, Common Yellowthroats, Hermit Thrushes, Black-billed Cuckoos, Scarlet Tanagers, Orchard Orioles and American Goldfinches have been heard singing not just near their nest, but while sitting on it! Warbling Vireos are by far the most persistent nest singers. When the male Warbling Vireo is incubating, he sings at all times of the day, as many as 20 bursts of song during one spell on the nest. Listening for the Warbling Vireo’s song and locating the songster can often lead you to its nest. One wonders what function the song has that makes it worth drawing this kind of attention to the nest.

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Showy Orchis Flowering

6-4-14 showy orchis 267A walk in deciduous woodlands at this time of year could result in the sighting of several species of orchids, one of which, Showy Orchis (Galearis spectabili), has a stalk of several flowers which typically bear lavender hoods (one variant is white). Potential pollinators, most of which are long-tongued bumblebees, butterflies, moths and bees, land on a white petal below the hood which acts as a “landing pad.” The insect next heads for the tip of the nectar-filled spur located at the back of the flower. In getting there it brushes against, and often picks up, packets of pollen (pollinia) before moving on to the next blossom, where cross-pollination ideally takes place. (Thanks to Ginny Barlow for photo op.)

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Beaver-Porcupine Encounter

beaver with quills2  376A Porcupine’s 30,000 quills effectively defend it against two and four-legged enemies, and occasionally against its own species. Rarely, however, do we see evidence of this mode of defense outside of our family dogs, most of whom are challenged when it comes to learning from the experience. From the size of the quills in this Beaver, one can assume it came in contact with either the Porcupine’s upper back or neck, where the quills are longest (up to 4”). How and where this encounter took place is a mystery. Porcupines can and do swim – their quills are filled with a spongy material which may enhance their buoyancy. So it’s within the realm of possibility that these two rodents met in the water, but that seems unlikely. While some quill injuries result in death, a surprising number of victims recover. One researcher observed that the quills he saw in a raccoon’s muzzle were worn down to a stubble within a week. Due to tiny barbs on the end of the quill that contacts another animal, it can work itself into an animal’s body, but those in this Beaver will hopefully come to rest against its jawbones. As long as the Beaver can eat, its chances of survival are good. It is unlikely to get an infection from the quills, as they’re coated with fatty acids that inhibit the growth of bacteria (in case the Porcupine stabs itself?)

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