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Adaptations

Birds Keeping Warm

1-3-18 dark-eyed junco2 049A1736

Birds utilize a number of behavioral adaptations that afford them some protection from frigid air such as we have been experiencing lately. They include sunning (turning their backs to the sun, exposing the largest surface of their bodies to the heat), shivering, tucking (placing one foot up inside feathers while standing on other leg, or squatting to cover both legs and feet with feathers; tucking their bill into their shoulder feathers and breathing air warmed by their body), roosting together in small groups (often in a small cavity, so as to conserve heat) and, most obvious of all, fluffing themselves up (creating air pockets that are warmed by body heat).

While feathers serve many purposes, from helping to attract a mate to providing camouflage, one of the most important jobs they have in winter is to keep a bird warm and dry. A bird’s body heat (the average bird’s body temperature is 105 degrees Fahrenheit), warms the air between its feathers. Birds fluff up in the cold to trap as much air in their feathers as possible, as the more trapped air, the warmer the bird. They can appear two or three times larger than they appear on a 32 degree day. This insulation is effective because it also is a barrier to water. The oil that birds apply to their feathers when they preen serves to waterproof the feathers. (Photo: Dark-eyed Junco)

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Oak Leaf Shapes & Sizes

11-15-16-oak-leaves-049a1752There are roughly 90 species of oak trees in North America, several of which can be found in New England. (Eastern White, Northern Red, Eastern Black, Burr, Common Chinkapin, Swamp White, Pin, Chestnut, Bear, Scarlet and Common Post). When identifying oaks, several characteristics, such as buds, bark, branching pattern and leaves, can be used. Most Northeastern species of oak have lobed leaves, with the lobes deep or shallow, pointed or rounded.

One thing all oak leaves have in common is their variability. Even on a single tree, you can find leaves of widely differing shapes. One reason for this is that the amount of sunlight that reaches them affects their shape.   Leaves that are shaded are not only often larger than those that are bathed in sunshine, but their lobes are far more shallow. Both of these traits maximize the intake of sunlight.   Canopies of oaks have a larger proportion of small, deeply-lobed leaves than lower down on the trees, where you can often find relatively large leaves that appear to lack lobes completely. The two pictured leaves come from the same Northern Red Oak.  Can you tell where on the tree they probably grew? (Thanks to Penny March for post idea and leaves.)

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Watershield Flowering

7-29-15  watershield 008Watershield is a perennial aquatic plant whose bright green, shield-shaped leaves float on the surface of shallow water in lakes and beaver ponds. Its small purple flowers bloom from June through September, with each individual flower only lasting two days. One the first day, the female flower parts (stigma, style, ovary) are mature. After receding into the water overnight, the flower re-emerges with mature male flower parts (stamens, filaments, anthers). The anthers burst open, releasing pollen to the wind, and the flower is then withdrawn below the water where the fruit develops.

The horizontal rhizomes, or stems, of Watershield, as well as the undersides of the leaves and developing buds, are covered with a thick, jelly-like slime. Botanists theorize that it may deter snails from grazing on these plants. Watershield secretes a number of chemicals that kill or inhibit growth of a wide range of bacteria, algae, and other plants.

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Water Scorpions

water scorpion 005These stick-like insects can be found inhabiting most freshwater ponds in the Northeast. Although called water scorpions, these water bugs aren’t even closely related to scorpions. Their name comes from the fact that they superficially resemble scorpions, with their modified grasping front legs and “tails,” which act as snorkels or breathing tubes. The long,slender water scorpions in the genus Renata are also referred to as water stick insects or “needle bugs.”

Water scorpions are formidable predators, reaching up to five inches in length. The majority of their diet consists of other invertebrates, but they have been known to take tadpoles and minnows.

Water scorpions mate at this time of year — males produce chirping noises, much like a cricket, to attract females. After mating, the female lays several eggs and attaches them to aquatic vegetation.

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Dragonflies & Damselflies Spear Prey With Lower Lip

7-27 dragonfly mouthpart 077Dragonflies and damselflies are unique among aquatic insect larvae in that they have a greatly enlarged hinged lower lip, or labium, which they can rapidly extend outwards to capture prey. When retracted, the prehensile labium fits like a mask over the face or is folded flat beneath the insect’s head. When hunting for prey, the dragonfly larva uses its labium like a speargun. It shoots forward as far as half the larva’s body length away, and moveable hooks on the front edge grab the prey. There are no muscles at the hinge/joint, leading entomologists to believe that the labium is extended by increased blood pressure caused by abdominal muscle contraction. It unfolds at a right angle, and extends extremely rapidly, faster than most prey can react. (photo: cast skin of dragonfly larva from which adult dragonfly emerged)

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Spittlebugs Feeding

7-15-15  spittle bug 049This strange-looking insect is none other than the nymphal stage of a true bug called a froghopper. During its immature stage, it is referred to as a spittle bug, due to the fact that while feeding on the sap of a plant it pumps excess water out of its abdomen (up to 150-300 times its body weight every 24 hours) and this water, combined with body secretions, turns into sticky bubbles which fall down over the nymph (it feeds upside down). The spittle provides thermal protection and prevents the nymph from drying out while it feeds for days in the sun. While seemingly drawing attention to the nymph’s presence, the spittle has a very bitter taste that would-be predators find unappealing. As an adult, the froghopper earns its name by being able to jump 100 times its length.

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Tree Swallow Nestlings Well Fed

7-21 tree swallows 068Tree Swallow parents begin feeding their four to seven nestlings as soon as they hatch, and they continue doing so until their young depart the nest and sometimes for several days afterwards. The adult carries food in its bill and places it directly into the open mouth of a begging nestling. The small insects gathered by the parent may be formed into a rounded ball, or bolus, which they hold in their mouth or throat (often not visible to an observer). Both parents feed the nestlings, together averaging about ten to twenty deliveries per hour. During periods of peak nestling demand, parents may feed as many as 6,000 to 7,000 insects in a single day. (Thanks to Jeannie Killam and Terry Ross for photo op.)

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