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Posts tagged “Cryptic Coloration

Question Mark Butterfly

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The butterfly known as the Question Mark is in a group of butterflies known as “commas” (a silvery comma can be seen on the underside of their hind wings) or “anglewings”  (for their sharply angled wing margins).  The Question Mark has a silver dot adjacent to the comma, turning it into a question mark.  When its wings are open, the question mark is fairly bright orange and quite noticeable, but when it closes its wings, it transforms into a dead leaf, for the undersides of its wings are dull brown and gray. This Question Mark was drinking sap from a wound in the trunk of a tree. These woodland butterflies prefer rotting fruit, mud, scat, carrion and tree sap over the nectar of flowers.

 


Brown Creepers Nesting

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The Brown Creeper is so well camouflaged that there are many people who don’t even know of its existence. This diminutive bird gets its name from its habit of creeping along tree trunks and spiraling upwards while it probes for insects and spiders hidden in bark crevices with its curved, sharp bill.  At this time of year, brown creepers have already made their fibrous nest behind a loose flap of bark on a tree, and the 5 – 6 nestlings are constantly demanding food.  Unlike some species, both adults care for their young.  These photos illustrate how the male goes off and finds an invertebrate, flies back to the nest and gives it to the female, who then disappears behind bark to feed it to her nestlings.


Delayed Greening of Young Leaves

Many plants practice “delayed greening” of their leaves, including this Red Maple (Acer rubrum).  An initial lack of chlorophyll prevents the leaves from photosynthesizing and making food, which means they have little nutritive value, and thus, appeal, to an herbivore.  Most plants that delay greening have reddish leaves due to the presence of anthocyanin, a pigment which appears reddish.  A majority of herbivorous insects and invertebrates cannot detect colors in the red range of the color spectrum. Young leaves suffer the greatest predation from invertebrate herbivores.  Red leaves would be perceived by these leaf eaters as somewhat dark and possibly dead – not a choice food material.  It is possible that the red coloration of new leaves allows the plant to make them unappealing to the herbivores that would otherwise eat them.


American Bittern

American Bitterns have returned to New England from their southern wintering grounds, and are announcing their presence with a unique song that Sibley describes as a “deep, gulping, pounding BLOONK-Adoonk” that they repeat over and over.  These secret, well-camouflaged marsh birds are almost invisible as they slowly walk through marsh grasses.  When they stand still and point their bill skyward, they are easily mistaken for the reeds they inhabit.

 


Cryptic Coloration

Can you find the brown creeper that’s on the trunk of this black cherry tree? This is cryptic coloration, a form of camouflage in which an animal blends into its environment, at its finest.  A forager of insects and spiders tucked away behind and in the crevices of bark, the brown creeper starts its search at the base of a tree, climbing upward and often spiraling around the trunk until it nears the top.  It then flies to the base of a nearby tree to begin the process again. As W.M.Tyler wrote in 1948 in Bent’s Life Histories of N.A. Birds, “The brown creeper, as he hitches along the bole of a tree, looks like a fragment of detached bark that is defying the law of gravitation by moving upward over the trunk, and as he flies off to another tree he resembles a little dry leaf blown about by the wind.”  


Mourning Cloak Butterflies

With the warm temperatures this week, mourning cloak butterflies have been seen gliding through the leafless woods.  Like eastern commas, question marks and red admirals, mourning cloaks overwinter as adults.  They resemble dead leaves so much that from a distance the entire insect seems to disappear.  Up close you can see the velvety texture of the wing scales, said to resemble the clothing mourners used to wear; hence, their common name. Mourning cloaks live up to ten months — an impressive life span for a butterfly.  As they age, the yellow border of their wings fades to an off-white.