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Articles by Wayne Bierbaum

A brilliant topic

A peacock’s tail is actually brown. But it possesses structural surface properties that create a bright rainbow of hues. The colorful display is due to iridescence.
    The simplest example of iridescence is the colorful shine of a drop of oil floating on water. When the oil film is thin enough, light gets bent as it hits the oil-water interface in a process called refraction. That light may be only one wavelength, one color, as determined by the thickness of the oil. The thinner the oil, the shorter wavelength of light that bounces back. The thicker spots are reddish and the thinner bluer.
    Animals of all sorts have created structural coloration not from pigments. In some, like a snake called the rainbow boa, it is from a thin film that changes thickness and color as the snake stretches and compresses while moving. Other colors are created by a static bio-coating or structures that create refraction of a particular wavelength, as with the peacock or the throat patch of a ruby-throated hummingbird.
    The angle of the light hitting the throat patch sometimes hits that sweet spot where the refraction amplifies the bounced light. In the photos presented here —taken within two minutes — the light was too bright for my camera’s sensor. 
    Iridescence is used for coloration by many plants and animals. It is, however, uncommon in mammals. 
    Look around and decide if the color you see is due to pigment or to light-bending iridescence.

Maybe that's because it's what this sparrow eats?

    Many animals are named by the sounds they make or the food that they eat. The grasshopper sparrow is named for both. These little birds live in grasslands from Canada to Florida, where they like to perch on any stick or fence and sing a song that sounds like a flying grasshopper. They also feed on grasshopper and other grasshopper-like insects.
    In the summer, they make nests by clumping grass near the ground. Thus their nests are at risk during hay cutting. Some farmers purposefully put off cutting while the birds are nesting. With fewer open grass fields, more grass cutting and many other reasons, the population has dropped 75 percent since 1968. The Florida sub-species is almost extinct.
    To help protect populations of grass-nesting birds and animals, most states have established large tracts of grasslands that are not cut until after nesting is finished. In Maryland, the largest tracts are at Fair Hill and Soldiers Delight, with a smaller grassland at Sands Road Park.

Don’t crowd this little bird off the beach

“The birds are taking over the beach.”     

            I heard that complaint as parts of a beach were being roped off because of nesting birds.

            The bird under protection is likely the tiny piping plover. 

            In the 1850s, piping plovers were very common along the East Coast and the shores of the Great Lakes. The population collapsed as they were hunted so their feathers could decorate women’s hats. The Migratory Bird Treaty Act of 1918 stopped the hunting, and the population stabilized.

            With human development along the coast, the population was again threatened. By 1986, just 790 breeding pairs survived on the Atlantic Coast. That is when they gained protection under the Endangered Species Act. Even with protection, the most recent surveys still place the Atlantic population at fewer than 2,000 pairs. 

            Piping plovers nest in small depressions in beach sand. They lay their speckled, sand-colored eggs in depressions about the size of a footprint. The eggs are very hard to see.

            The eggs take 25 days to hatch, emerging at about the size and shape of a miniature marshmallow. The tiny chicks hide by freezing in place, as they cannot fly for another 30 days. Eggs and young are very vulnerable to predatory animals and to being stepped on or run over by motor vehicles and bikes.

            Adults also have difficulty feeding the chicks when people are too close. After the chicks have learned to fly, they are no longer as vulnerable. By September, the plovers start their migration south along the Florida coastline to the Bahamas.

            These little birds need space to survive as a species. Four thousand birds along the hundreds of miles of Atlantic coastline is not very many. Help them out by avoiding nesting areas, and keeping your pets out, too.  

Sponsoring a Bluebird Family

      In December 2007, we had an early snow. While taking a brisk walk through the neighborhood, I saw a small flock of Eastern bluebirds in a holly bush eating the snow-capped berries. That was the first time I saw any near where I lived. I had always thought that they were an uncommon and special bird. 


Enjoy but leave only footprints

     I recently took a walk through Quiet Waters Park in Annapolis and was struck by the number of people using the space. 

Rare birds forced south by winter

     When winter arrives, avian guests do, too. Northern birds rarely seen here are sometimes forced into our area during this season. In 2013, arctic-dwelling snowy owls began flying around the shores of the Chesapeake Bay. A few were spotted at Sandy Point State Park and one caused a traffic jam as it landed on the signs hanging overhead on the Bay Bridge. 
    Two weeks ago, I was driving alongside a large field on Maryland’s Eastern Shore and saw a spectacular display of coordinated bird flight. A flock of hundreds or even thousands of red-winged blackbirds were flying in a tight formation while turning and flowing—also called a murmuration. 
     On the winter’s solstice, I walked through Beverly Triton Nature Park in Edgewater. Previously, I had seen one or two eagles around the edges of the park but on that special day, I counted a full dozen—a mixture of white-headed adults and darker juvenile eagles. 
     They were located around the pond in the middle of the park and seven were sitting in one tree. 

Part of our Chesapeake watershed ecosystem

     Earlier this month, someone spread popcorn on the parking lot at the Laurel Plaza shopping center on Fort Meade Road. When a flock of ring-billed gulls started feeding, they were targeted by a driver who managed to kill ten birds. This act of animal cruelty was reported nationwide along with a $5,000 reward for information.
These intelligent birds have plenty to talk about
      The winter brings feathered visitors from the north to the Chesapeake Bay. For anyone that lives near the water, it becomes obvious that waterfowl are suddenly more common as they escape the frosty north.