An online resource based on the award-winning nature guide

Feathers

American Bitterns Displaying

5-3-14  American Bittern3  058American Bitterns are very secretive marsh-dwelling birds and have coloration so cryptic that you can be looking right at one and not see it, especially if it employs its “look like a reed” stance, with bill raised towards the sky. Like other members of the Heron family, American Bitterns possess plumes. These large, white shoulder feathers are visible only at this time of year, during territorial and courtship displays and just prior to copulation, when they are erected. Not only do these plumes impress female bitterns, but they make it much easier for humans to spot the displaying males.

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Ruffed Grouse Wings

2-25-14 grouse wing imprints  010You can often determine the type of flight that a bird is capable of by looking at the shape of its wings. Long, narrow wings are excellent for gliding, while the short, rounded wings of a Ruffed Grouse allow for tight maneuvering in the dense forests where they live. The shape of their wings and their quick-contracting muscles equip grouse for the short bursts of high speed (not long distances) they take when feeding or evading predators. (Photo: a Ruffed Grouse walked a short way and then took flight, beating its wings against the snow twice before it was airborne.)

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Big Birds

blue jay puffed out in snow 101Is your bird feeder being visited by gigantic Blue Jays and Black-capped Chickadees during this cold spell? Your eyes aren’t fooling you; birds often appear larger in very cold weather.
Birds that remain in New England year round must not only be able to find enough food in the winter to produce heat and energy, they must find a way to retain the heat. Various strategies have evolved, but feather structure and function play an important role for the winter survival of all birds. There are different types of feathers, each designed for a different function. A (wing or tail) feather consists of a central, hollow shaft on either side of which are many interlocking rows of barbs. The feathers that cover the body of a bird (contour feathers) often have interlocking barbs only at the ends, on the part not covered by an overlapping feather. The bottom-most, unconnected barbs on these feathers are similar to those of down feathers – loose and fluffy. When the temperature dips, birds often puff out their contour feathers (making the birds look huge). This action, and the structure of the bottom portion of the contour feathers,
increase the number and size of air pockets between the bird’s feathers and its skin. This space provides excellent insulation, preventing much of the bird’s body heat from escaping.

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Waterfowl Vulnerable When Molting

8-23-13 canada goose remains 043All North American birds replace their old, worn plumage with new feathers at least once a year, a process known as molting. Most birds have what is called a “sequential molt,” in which their flight feathers are lost one at a time (from each wing). This allows many birds to continue flying while molting. However, during their annual molt, waterfowl undergo a “simultaneous wing molt,” losing all of their primary wing feathers at once, preventing them from being able to fly for a month or more while their new primaries are growing in. During this period, they are extremely vulnerable, as this photograph testifies to. If you look closely at the remains of the Canada Goose’s wing on the right in the photograph (dark feathers), you’ll see that the new primaries have almost, but not quite, grown out of their sheaths, making them not yet functional. It’s apparent that this bird was unable to take flight during its molt in order to escape its predator.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Common Grackle Threat Display

5-3-13 common grackle DA8A1629Although the common grackle, a member of the blackbird family, is the bane of many corn growers as well as a threat to songbirds trying to raise young (grackles eat other birds’ eggs and nestlings), it is quite a colorful bird, with its pale yellow eyes and iridescent purple plumage. Grackles have already begun nesting and defending their territory, as can be seen from the stance of the bird in this image. This “bill-up display” is a position assumed when a male is being approached on its territory by another male. It moves its head upwards so that its bill is almost vertical, signaling to the approaching grackle that it would be in its best interest to depart.


Red-winged Blackbird Epaulettes

3-11-13 redwing epaulettes IMG_2348Male red-winged blackbirds have returned to Vermont, and their most notable features are the brightly-colored reddish-orange feathers on their “shoulders”, referred to as epaulettes. In the military, an epaulette is a shoulder ornament that indicates, through its position, color, length and diameter, the bearer’s rank. Some birds, including male redwings, also possess this badge, or visual cue, which indicates the social status of the bird to other birds of the same species. Studies of male red-winged blackbirds and their epaulettes indicate (through dyeing their bright orange/red shoulder patches black) that epaulettes play a significant role in the male’s defense of his territory. Over 60% of the redwings that had their epaulettes dyed black lost their territories to other males. Further research revealed that aggression by a territorial male redwing is proportional to the epaulette size of the encroaching male redwing. It also indicated that male redwings intruding into redwing-occupied territories greatly limit the exposure of their epaulettes by covering them with black feathers. (Female red-winged blackbird plumage is brown and lacks epaulettes.)


Avian Heat Regulation in Winter

1-9-13 mallards on ice IMG_0203On a cold, winter day, why would any bird choose to sit down on ice? While feathers are excellent insulators, the legs and feet of most birds lack this protective covering. Because of this, legs and feet are a major source of heat loss for birds. Physical adaptations to this loss of heat include constricted blood vessels in a bird’s feet, as well as the proximity of arteries and veins to each other which aids the transfer of heat. Birds exhibit behavioral adaptations as well, such as ducks and gulls standing on one leg and tucking the other among breast feathers, reducing by half the amount of unfeathered limb surface area exposed. By sitting down and covering both legs, even on ice, heat loss from limbs is minimized. If you observe closely, you will see many of the ground-feeding finches such as sparrows and redpolls also occasionally drop down and cover their legs and feet with their breast feathers for a few seconds.


A Great Christmas Present!

If you’re looking for a present for someone that will be used year round, year after year, Naturally Curious may just fit the bill.  A relative, a friend, your child’s school teacher – it’s the gift that keeps on giving to both young and old!

One reader wrote, “This is a unique book as far as I know. I have several naturalists’ books covering Vermont and the Northeast, and have seen nothing of this breadth, covered to this depth. So much interesting information about birds, amphibians, mammals, insects, plants. This would be useful to those in the mid-Atlantic, New York, and even wider geographic regions. The author gives a month-by-month look at what’s going on in the natural world, and so much of the information would simply be moved forward or back a month in other regions, but would still be relevant because of the wide overlap of species. Very readable. Couldn’t put it down. I consider myself pretty knowledgeable about the natural world, but there was much that was new to me in this book. I would have loved to have this to use as a text when I was teaching. Suitable for a wide range of ages.”

In a recent email to me a parent wrote, “Naturally Curious is our five year old’s unqualified f-a-v-o-r-I-t-e  book. He spends hours regularly returning to it to study it’s vivid pictures and have us read to him about all the different creatures. It is a ‘must have’ for any family with children living in New England…or for anyone that simply shares a love of the outdoors.”

I am a firm believer in fostering a love of nature in young children – the younger the better — but I admit that when I wrote Naturally Curious, I was writing it with adults in mind. It delights me no end to know that children don’t even need a grown-up middleman to enjoy it!


Juvenile Cedar Waxwings Migrating

Possibly because of the importance of summer fruits in their diet, Cedar Waxwings (Bombycilla cedrorum) are late nesters, but by late August adults have begun their migration to the southern states and Central America.  This year’s young are beginning this (roughly) 900-mile flight now, a month after their parents have left. You can often find waxwings feeding in crab apple and other fruit trees where they stop over during their flight to refuel.  Juvenile birds lack the sleek look of adults — the red wax-like feather tips for which this bird is named have not developed, and the color of their plumage is much duller than that of the adults.


Juvenile Green Heron

Green herons are typically solitary and secretive birds, but if you find one, you often have an extended period of time to observe it, as they often slowly stalk their prey, or pose statue-like, sometimes for minutes at a time, while waiting to strike at a fish, frog or invertebrate. Three characteristics tell you that the green heron in the photograph is a juvenile: the tufts of down that remain on its head, its streaked neck (adults have solid rufous necks) and its yellow legs (adults have orange legs).


Red-tailed Hawk Nestling

The Red-tailed Hawk nest that produced two fledglings last year is in use again this spring.  In the past month the nestlings have gone from tiny white powder puffs to nearly equaling their parents in size.  Down is still visible, especially on their heads, but contour feathers are quickly replacing them on other parts of their body. Soon there will be wing stretches and flapping, as well as hopping about on nearby branches in preparation for fledging. 

 


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.

 


Snow Buntings

Snow Buntings begin arriving in the northern half of the United States from their summer home on the northern tundra by the end of October, and remain here until March, when they begin migrating back to their breeding grounds. Although both males’ and females’ backs and heads are brownish, their bellies and a good portion of their wings are white, and when they take to the air, a flock of snow buntings bears a strong resemblance to a massive snow storm. By the time their breeding season arrives, the male has a totally white head and belly, and a jet black back.  This is not because of a second molt – snow buntings only molt their feathers once a year in the late summer – the change in appearance is due to the fact that underneath the colored feather tips, the back feathers are pure black and the body feathers all are white. The male wears off all of the feather tips by actively rubbing them on snow, which produces his black and white breeding plumage. (There is one male snow bunting in this photograph that is close to having breeding plumage — can you find it?)

 


Cedar Waxwing Feather

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Several of the secondary flight feathers (inner wing feathers) of Cedar Waxwings and Bohemian Waxwings possess tiny, brilliant red tips. (As Dale Martin pointed out, there is a bit of white next to the red tips of Bohemian Waxwings’ feathers, but those who guessed either waxwing should take a bow.) These “waxy droplets” give the bird its common name, along with its love of red cedar berries.  These drops of “wax” are actually the widened, flattened ends of the feather shafts.  The color is derived from a carotenoid pigment, astaxanthin, which they get from their diet (cedar fruit and other berries).  Younger birds possess fewer red tips than older birds. Ornithologist Peter Stettenheim conjectures that since the waxwing’s ability to find berries probably improves with age, the number, size and coloration of these tips may indicate the birds’ foraging ability.  Research in the 1980’s indicates that these red tips serve as markers in mating, providing visual clues to potential mates about each other’s age, which correlateswith egg size, clutch size, as well as ability to find and deliver food.  Cedar Waxwings tend to mate with individuals of their own age.  


Mystery Feather

To be identified tomorrow!


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