The Simple Beauty of Sparrows

White-crowned Sparrow, Zonotrichia leucophrys

Coming from the Anglo-Saxon word ‘spearwa’ and literally meaning ‘flutterer’, sparrows often conjure up images of the ubiquitous and non-native House sparrow and the House finch, which isn’t a sparrow at all.  While most sparrows are generally small to medium brown birds with streaks, the differences between sparrows can best be determined by their relative size, head markings, and habitat.

White-throated Sparrow, Zonotrichia albicollis

All sparrows have conical bills that they use to shell seeds, a primary component of their diet year-round, but especially so in the winter months.  There is little difference between the males and the females in terms of appearance, but males are on average larger than females.  As a group, most sparrows are birds of grasslands, prairies, and marshes, and seem to prefer weedy fields and woodland edges in the winter.  Of the sparrow species that migrate, none travel further than the southern United States or northern Mexico.

Chipping Sparrow, Spizella passerina

One of our most common winter sparrows is the Chipping sparrow.  Small and slim, with a long notched tail, rusty cap, white stripe over the eye and a black line through the eye, this sparrow moves in loose flocks and frequently feeds in short grass and open woods.  While still fairly abundant, this sparrow is declining in numbers, mainly due to habitat destruction, and winters in the southern part of the United States.  When first identified in 1810 by an American ornithologist, it was nicknamed ‘the social sparrow’ for it was easily approached and associated with human habitation.

White-crowned Sparrow, Zonotrichia leucophrys 

A fairly large sparrow, the White-crowned sparrow is distinguished by its black and white striped head, unmarked gray breast, and dark pink bill.  It is found in large groups in thickets and weedy areas, foraging on the ground.  Discovered in 1772 by a German naturalist, this sparrow was originally named the ‘white-eyebrowed bunting’, for in the Old World, sparrows were usually called buntings. 

Found in a variety of grassy habitats, and often in small flocks, is the Savannah sparrow. Streaked on both their back and their breast, Savannah’s have pink legs, yellow above the eye, a thin white median crown stripe, and a short notched tail.  First described by a British ornithologist in 1790, it was called a ‘sandwich bunting’ due to the first specimens being collected from Sandwich Bay in the Aleutian Islands of Alaska.   

Lincoln's Sparrow, Melospiza lincolnii

Lincoln’s sparrow is a medium-sized bird with a rather short tail, broad gray stripe above the eye, buffy moustache stripe, and a buffy upper breast with crisp, blackish streaks.  Found in winter in brushy edges of ponds and other moist areas, this sparrow was named by John James Audubon in 1833 after his research companion, Thomas Lincoln, shot the first specimen in Labrador.       

Sparrows are gregarious and are often our most hardy winter visitors.  Adorned in various shades of brown, gray, black, and white, they reflect the subdued hues of a winter landscape.  Often dismissed as ‘little brown birds’ when seen with the naked eye, these birds invite closer inspection and are nature’s way of reminding us that subtle colors and patterns can be beautiful, too!   

Leafy Treasures

Fall is the time when the quiet, green palette of summer gives way to the crisp reds, vibrant oranges, and mellow yellows that paint the natural landscape.  During the growing seasons of spring and summer, our trees and shrubs use sunlight to convert water and carbon dioxide from the air into sugar.  Called photosynthesis, this process begins to wane in November in Central Texas, and the leaves on some plants begin to change color in preparation for winter’s rest.

Texas Red Oak, Quercus buckleyi

Pigments are natural substances formed by the cells of leaves which provide the basis for leaf color.  Most familiar is chlorophyll, which produces the color green, and is vitally important as it is required for photosynthesis.  Carotenoid, which produces the colors yellow, orange, and brown, is a common pigment in many fruits and vegetables, as are anthocyanins, which produce the color red.  Both chlorophyll and carotenoid are present at the same time in leaf cells, but the chlorophyll covers the carotenoid and hence the leaves appear green in the spring and summer.  Not all trees can make anthocyanins, however, and most are produced under certain conditions and only in the fall.

Mexican Buckeye, Ungnadia speciosa

As the days grow shorter, the decreasing amount of sunlight eventually causes trees to stop producing chlorophyll.  When this happens, the carotenoid in a leaf can finally show through, turning the leaves into a myriad of yellows, oranges, and browns.  Red, on the other hand, is an entirely different matter.  Affected by temperature and cloud cover, red fall colors can vary greatly from year to year.  A lively showing of reds depends upon warm, sunny autumn days and cool, but not cold autumn nights.  This type of weather pattern triggers the production of anthocyanins, which the tree produces as a form of protection.  Anthocyanins allow trees to recover any sugar or nutrients left in the leaves, moving them through the leaf veins and down into the branches and trunk, and its presence generates the red color before the leaves fall off.  Rainfall during the year can also affect fall color, with too much lowering the overall color intensity, and too little delaying the arrival of color.

Virginia Creeper, Parthenocissus quinquefolia

Fall leaf color can easily be used to help identify local tree and shrub species.  The most notable reds and oranges in our area are produced by Texas Red Oak and Flame-leaf Sumac.  Dotting the hillsides, roadsides, and upper reaches of wooded canyons, they contrast well with the surrounding greens of Ashe Junipers and Live Oaks.  Golden yellows are represented by Eastern Cottonwood and Escarpment Black Cherry, whose color transforms the low-lying areas near creeks and streams.   

Flameleaf Sumac, Rhus copallinum

While a tree’s trunk and branches can survive the colder winter temperatures, many leaves cannot.  Made up of cells filled with water and sap, these tissues are unable to live throughout the winter, and the tree must shed them to ensure its survival.  As the days grow shorter, the veins that carry sap to the rest of the tree eventually close.  A separation layer forms at the base of each leaf stem, and when complete, the leaf falls.  Some oak trees are the exception, with this layer never fully detaching and the dead leaves remain on the tree until new spring growth pushes them off to the ground.  Once on the ground, the leaves slowly decompose with the help of earthworms, beneficial bacteria, and fungi, creating the soil necessary for the continuation of the cycle of life.