House Sparrows – II

By in Behavior, Reproduction, Species Accounts

In the last column, we explored the biology of House Sparrows.  This species is dependent on human-altered landscapes for their existence. The abundance of House Sparrows and their tolerance of human proximity make House Sparrows excellent subjects for ornithological research.  In today’s column, I will review some of the research on these birds.

House Sparrows can change habitat preferences quickly. Introduced into eastern North American 1n 1851, House Sparrows were most common in cities.  Until the turn of the 20th century, urban areas where perfect for House Sparrows. Horses provided the major means of human transportation and the hay to feed to horses had plenty of seeds to satisfy the cravings of House Sparrows.  Many seeds pass through a horse gut intact so horse droppings provided good foraging as well.

As automobiles replaced horses in cities, House Sparrow abundance in cities declined and the birds shifted their preference for agricultural landscapes. The primary food of most House Sparrows is now cereal grains like wheat, corn and oats.  Some Argentinian House Sparrows make ends meet in urban environments by feeding on the nectar produced by aloe plants in public parks.

House Sparrows have provided a test of Bergmann’s Rule.  This rule states that the size of members of a species (or related species) should increase as one goes from the equator to the poles.

The reason is related to the challenges of maintaining a constant body temperature at colder temperatures. A larger animal has a lower surface to volume ratio.  Heat is lost across the surface of an animal but produced by all the cells in the body, hence proportional to volume. In seasonal environments where food abundance is highly variable, a larger animal will be able to tolerate lack of food longer than a smaller animal.

Studies of the geographic variation in size of House Sparrows in North America provide support for Bergmann’s Rule.  From an initial introduction, House Sparrows have spread broadly throughout North America.  Size is negatively correlated with average January temperatures and size is positive correlated with latitude.  In Europe, the pattern is murky. No strong pattern of increase in size occurs with increasing latitude.  More work is needed.

Male House Sparrows have a black bib.  Animal behaviorists call such a feature a badge.  The extent of the black is an advertisement for the quality of the male; females choose a mate, at least in part, based on the size of his badge.

We know that males with larger birds acquire a mate earlier than small-badged males.  Large-badged birds also usually have superior nesting territories.

We think of House Sparrows as monogamous birds. From DNA fingerprinting, we know that cheating on a spouse is common in House Sparrow communities. About 20% of nestlings are sired by a male other than the female’s mate.

Research in Sweden indicates that large-badged males are received more frequently in extra-pair dalliances than small-badged males.  The tables can be turned.  The mate of a large-badged male is often cheated on by his mate.

Some House Sparrows in New Zealand are clever birds indeed.  In Hamilton, House Sparrows fly into the bus station when the automatic glass doors slide open, activated by an electric eye. The House Sparrows find plenty of food to eat from the crumbs that humans drop from their breakfasts and lunches purchased inside.  The Hamiltonians are very tolerant of the scavenging House Sparrows.

A hungry House Sparrow needs to wait for a human to enter or exit the bus station so the doors slide open.  However, some House Sparrows have figured out they can perch on top of the small metal box above the door that houses the electric eye.  The birds lower their head to break the laser beam and, voila, the door opens when the sparrows want to get in.

House Sparrows – I

By in Species Accounts

I’ve just returned from a late July meeting in Miami.  Alas, I had no free time to go birding but I certainly saw many Rock Pigeons and House Sparrows.  One expects to see these two species in any urban environment.

The two species are both introduced species.  In North America, they are rarely found very far from human-altered landscapes.  I see a fundamental difference in the habitats of these two species.

A couple of decades ago, my wife and I had the pleasure of touring Scotland.  At the northeast tip of Scotland at John O’Groats, we had the pleasure of seeing wild Rock Doves. The birds were nesting on the dramatic cliffs and permitted no close approach by humans.

Obviously, humans befriended some Rock Doves, which readily adapted to urban and agricultural habitats. Don’t expect to see Rock Doves in Baxter State Park or other areas with sparse human population density.

Finding House Sparrows in a city is a snap.  But where you would you go to find House Sparrows in the wild?  A small population of House Sparrows in the Middle East associated with natural grasslands are the only “wild” House Sparrows extant.  This population is genetically distinct from all other House Sparrows.

The vast majority of House Sparrows are associated with humans.  The “natural” habitat of House Sparrows is best described as human-altered landscapes.

With the exception of the Middle East grassland House Sparrows, these birds have married their fortunes together with humans.  The presence of humans has certainly facilitated the natural spread of the species into Europe and Asia.

The original range includes northern Africa and most of Eurasia.  The species has been introduced to North and South America, Australia and New Zealand. Pinning their success to humans, House Sparrows are doing well. They certainly outnumber humans on this planet.

House Sparrows were introduced in North America by releases of birds in Brooklyn in the fall of 1851 and the spring of 1852.  The invasion of North America was aided by subsequent introductions in San Francisco in 1871 and 1872 and in Salt Lake City in 1873 and 1874.  Now House Sparrows are found throughout the Lower 48 states except for southwest Texas and are found over much of Canada.  They have not become established in Alaska yet, likely because the relatively sparse human populations in that state to provide House Sparrow habitat.  Birders in Alaska have found occasional strays including five from northwestern Alaska that may have arrived from Siberia.

An introduced species may wreak havoc on native species. House Sparrows certainly compete with birds that live and nest in our urban, suburban and agricultural habitats.  House Sparrows readily nest in cavities.  Bluebirds, Tree Swallows and House Wrens may lose nest cavities to House Sparrows.

From personal experience, I know that House Sparrows will enter nest boxes occupied by bluebirds and kill the nestlings and then take over the nest box. An effective way to deter House Sparrows is to have the nest box openings no greater than 1.25 inches in diameter.  That opening give access to bluebirds, swallows and wrens but not the chubbier House Sparrows.

The diet of adult House Sparrows is primarily seeds. In agricultural areas, House Sparrows may become pests on cereal grains.  Parents feed their young insects.

In 1958 in China, Mao declared House Sparrows to be one of four pests that needed to be eradicated. The Chinese citizens were told to kill as many House Sparrows as possible.  Perhaps over a billion birds were exterminated.

Rice crops seemed to improve at first but the insects feeding on the crops increased rapidly in the absence of the House Sparrows.  More rice was lost to the insects than to House Sparrows. Mao reversed his position, ordering the protection of the House Sparrow. Rice crop production improved thanks to the dietary needs of nestling House Sparrows.

Sandhill Cranes in Maine; Mallards and Field Guides

By in Field Guides, Species Accounts

In 2000 and 2001, Scott Melvin documented breeding by a pair of Sandhill Cranes at the southern end of Messalonskee Lake in Kennebec Count.  This exciting discovery was the first record of breeding by this species in the state.

Multiple pairs now nest in this area.  In addition, Maine birders have found other Sandhill Cranes in the late spring and summer.  These locations include North Yarmouth, Auburn, Leeds, Chelsea, Manchester, Fryeburg, Smithfield, New Gloucester, Orland, Surry, Unity and Mount Desert Island.  At least some of these cranes may be breeders as well.

The breeding range of Sandhill Cranes spans the western two-thirds of Canada into Alaska with some birds breeding in Minnesota, Wisconsin and Michigan.  Most of these birds winter in west Texas, southern New Mexico and northern Mexico.

The birds migrate in groups with families staying together. The birds fly in the efficient V-formation.  Birds tend to stop at traditional stop-over areas, the Platte River in Nebraska being one of the best known.  In the spring, half a million cranes stop along 70 miles of the Platte River, delighting birders and naturalists.

A resident, non-migratory population occurs in peninsular Florida.  The first Sandhill Crane I ever saw flew above me when I was running a road race in Melbourne, Florida. The size, color and the extended neck (different from the S-shaped, recurved neck of a heron in flight) clinched the identification.

We know that some bird ranges are expanding or changing. Most of these changes we attribute to global climate charge. Fifty years ago, Turkey Vultures, Tufted Titmice, Carolina Wrens, Northern Mockingbirds, Blue-winged Warblers and Northern Cardinals were not a part of Maine’s avifauna.

But how do we explain the arrival of Sandhill Cranes as breeders and migrants in Maine when Maine is south of most of their breeding areas?

We know that the population of Sandhill Cranes in Minnesota, Wisconsin, Michigan and western Ontario is doing well.  The populations there nearly doubled between 1980 and 1995 and continues to grow. Some of these birds seem to be dispersing east. Recent nesting has occurred in northwestern Pennsylvania, southeastern Ontario and Quebec.

We do not know if the recent breeding in Maine represents a true range expansion or a recolonization of a species that was extirpated 200 years or more. We have some evidence from historical accounts from the 1600’s and 1700’s referring to cranes in Maine and Nova Scotia.  However, those authors may have confused cranes with herons.  It does seem clear that some cranes migrated all along the eastern seaboard in the 1600’s before succumbing to human depredation.

If you want to see these magnificent birds, Messalonskee Lake is the place to go.  From I-95, take exit 112 in Augusta and head northwest on Route 27 for about 7 miles.  On the right, there is a parking area where a former motorboat launch was located.  Scan to the south from the floating dock.

Then go 0.2 mile north to Hammonds Lumber. From the parking lot, scan the marsh.  A little patience will usually reveal a crane or two.

Mallards in Maine

Mallards are common birds in Maine.  Even the most casual Maine birder has likely seen this species in our state.  However, you wouldn’t think so based on the maps in several bird field guides.  Jane Coryell has been enjoying Mallards for years on Togus Pond in Augusta.  She happened to notice that the Peterson Field Guide, the Stokes Field Guide and the Sibley Guide to Birds (First Edition) all fail to show that Mallards occur in Maine on the range maps!  Is this error a coincidence or perpetuation of an error by one author in other author’s field guides?  This oversight is yet one more example of why we should be skeptical about what we read.  Paper does not refuse ink.

Bird Nests

By in Reproduction

The nesting season continues apace for many Maine breeding birds.  Finding a bird’s nest can be difficult during the incubation period when the incubating parents are still and rarely leave the nest.  For songbirds and other birds whose young require feeding (altricial birds), the necessity of frequent visits to the nest to satisfy the seemingly insatiable appetites of the nestlings makes it easier to locate nests after the chicks have hatched.

Birds of a given species make similar nests.  Nests range from small depressions in the forest floor or on a sandy beach to massive structures weighing more than a ton.  In today’s column, I will provide an overview of the diversity of bird nests.

The simplest nests are scrapes on the forest floor, fields or beaches.  The nest of a Killdeer is a good local example.  The female lays four eggs in a nest scrape just big enough to contain the eggs.  As you would expect, the eggs are well camouflaged.  In the woods, American Woodcocks and Whip-poor-wills create nest scrapes for their eggs.  For most species that create nest scrapes, little effort is made to line the nests with soft material.

Most birds construct a bowl-shaped nest just large enough to fit an adult’s body.  We can consider the bowl-shaped nest of an American Robin as a typical nest.  Robins are not great architects but still have a remarkably complex nest.  The outer part of the nest is formed of twigs, coarse grass and sometimes pieces of cloth, string or other human-made products.  This outer layer gives the nest strength.  Within this outer layer, robins place a smooth layer of mud.  Finally, a layer of fine grasses is laid down to surround the eggs and aid in insulation.  Once the outer part of the nest is built, the female sits in the middle of the nest for the rest of the construction.  A snug fit is therefore guaranteed for the incubating mother.

Other species use specific materials for the inner lining of their nests.  Palm Warblers, a ground-nesting species in bogs, often place Ruffed Grouse feathers in their nests.  Tree Swallows line their nests with feathers, particularly white ones.  In the early breeding season, you can see aerial fights where Tree Swallows attempt to take white feathers from another Tree Swallow.

Ruby-throated Hummingbirds create tiny nests to hold their two eggs.  The nest is made of down and small pieces of plant material bound together with spider webs.  The outer part of the bowl is covered with bits of lichens to aid camouflage.

Black-capped Chickadees make their nests in a tree cavity.  The outer part of the nest is made of moss and the inner part of spider webs, soft grasses and plant down.

Waterbirds typically create bowl-shaped nests on the margins of lakes or ponds or even on floating vegetation.  In most cases, the outer layer of the nest is made primarily of vegetation.  If water levels rise, waterbirds will quickly add additional vegetation to keep the inner part of the nest dry.  The inner lining is made in part of down feathers that the female pulls from her breast.  These down feathers create a wonderfully warm place for the eggs.

The largest nests in Maine are made by birds of prey.  An Osprey nest may be five feet across.  The outer portion is made of sticks and miscellaneous debris.  The inner lining is made of smaller twigs, grasses and other soft material.

Bald Eagle nests are larger yet.  Some nests may be eight feet in diameter and 12 feet high, weighting over a ton!  Like Ospreys, Bald Eagles use the same nests year after year, adding material to the nest each spring.

A good source for identifying nests based on their structure and location is http://nestwatch.org/learn/how-to-nestwatch/identifying-nests-and-eggs/

Rails in Maine

By in Species Accounts

Inspired by the recent June sighting of at least two King Rails in Wells, I am devoting this column to one of the least appreciated groups of birds in Maine, the rails.  Our rails are marsh birds, infrequently seen but often heard.

These birds belong to the avian family Rallidae, a group that also includes the coots.  Coots are duck-like in their behavior and by no means secretive.  I’ll stick to the rails in this column.

Rails have short, rounded wings.  Despite the meager surface area of their wings, many rails are migratory. Lots of oceanic islands have been colonized by these unlikely migrants. Once on an island, rails speciate to form an endemic species. Alas, most of these endemic island rails are extinct, primarily due to direct or indirect effects of humans.

Rails are predators, preying on insects, spiders, crayfish, snails, other invertebrates, small fish and even seeds.  Bill length varies quite a bit between species but always serves as an effective forceps to grab single prey items.  Rails have long toes, allowing the birds to walk through muddy areas without sinking into the mire.

The body of a rail is laterally compressed.  Imagine putting your hands on either side of a balloon and pressing in.  The balloon becomes thin and tall.  This body shape in rails certainly helps them move through the dense vegetation of a cattail marsh or a salt marsh.

My wife and I had an argument about the derivation of the term “thin as a rail”. My claim was the phrase refers to the thin width of one of these marsh birds. My wife claimed the reference is to the split logs used to make fences. We decided to enlist the aid of a Colby reference library who disabused me of my interpretation. Nevertheless, thin as a rail fits for these birds.

We have five rails in the state.  Two of them, the Virginia Rail and the Sora, are common in the summer throughout Maine.  Clapper Rail, King Rail and Yellow Rail are rare birds for the state.

The Virginia Rail is a handsome bird, nine to ten inches long.  A rusty breast, olive-brown dorsal surface, flanks striped with black and white, a gray cheek patch and a long, red bill make these birds sharp dressers.  Alas, their secretive nature means a fleeting glimpse is all you can expect. Their presence in a marsh is usually given away by their insistent clicking vocalizations as well as pig-like grunting.

Our other regular rail is the Sora. A bit smaller than a Virginia Rail, a Sora has a gray neck and breast, black face and a short, bright yellow bill. The common name comes from a rendering of one of their vocalizations, a two-note whistle.  They also give a downward spiraling whinny.  The twilight hours are best for hearing these remarkable calls.

On May 10, Bri Benvenuti photographed a King Rail along Eldridge Road in Wells.  Other birders learned of this rail on June 7 and birders have been flocking in Wells to see this local rarity.  We know there are at least two present. This sighting represents the seventh record of the species in the Maine and the first in 20 years.

As the name suggest, King Rails are large birds, about 15 inches long.  Their mostly cinnamon feathering camouflages them well. Fortunately, they like to forage along the water’s edge so are often seen along the marsh edge.

Clapper Rails are very similar to King Rails.  Identification requires a good look at the edges of the contour feathers (buff in King Rail, gray in Clapper). That’s a tough task in such secretive birds.  We have six records from Maine, the latest being from 1973 in Wells and last September in Scarborough.

Finally, the small Yellow Rail is probably more common than we know.  They seem to migrate through Maine from mid-September through mid-November.

Review of “Listening to a Continent Sing”

By in Book Reviews, Vocalizations

The first half of June is the best time of the year for bird song in Maine. Male songbirds sing insistently, hoping to win the favor of an available female.  Males also sing to ward off marauding males from their own territories.

Our sophistication in listening to bird song and our enjoyment have been greatly facilitated by the writings of Don Kroodsma.  An emeritus professor at the the University of Massachusetts, Kroodsma has been studying bird vocalizations for over 40 years.  In 2003, the American Ornithologists Union hailed him as “the reigning authority on the biology of avian vocal behavior”.

k10668Kroodsma has an insatiable curiosity about bird vocalizations and also a deep passion for his subject. He certainly shares Shakespeare’s observation that “The earth has music for those who listen”.  Kroodma’s curiosity, scientific rigor and passion are all on display in his popular books.

In 2005, Kroodma’s “The Singing Life of Birds” appeared to great acclaim. In easily accessible language, Kroodsma takes the reader through many aspects of bird vocal behavior including song learning, dialects, the functions of song, singing by females among others. The book provides thorough training in the interpretation of bird song.

In this book, Kroodsma provides sonograms for many vocalizations. These graphics show the duration of individual notes and their rise or fall in pitch. He argues that hearing by seeing is a powerful tool.

The latest book by Kroodsma has just appeared and it is wonderful as well.  The book is titled “Listening to a Continent Sing: Birdsong by Bicycle from the Atlantic to the Pacific). The book is an account of a 70-day cross-country bike excursion he made with his son David in 2003.  Kroodsma was 56 years old at the time and David was 24.  The book is an engaging mix of travelogue and natural history with a little bit of geology and anthropology for good measure.

Most cross-country cyclists travel from the West Coast to the East to take advantage of prevailing westerly winds to aid their journey. Many cyclists prefer to ride in the afternoon when those winds are stronger and the sun is behind them.  However, our duo decided to ride in the opposite direction, despite frequent headwinds. The purpose of the trip was to hear the songs of the breeding birds.  The breeding season arrives late in the Cascades and Rockies.  An eastward trip would mean they would miss most of the breeding season east of the Mississippi because they would need to be in the Rockies no earlier than mid-June.

As you can imagine, Kroodsma’s early morning trips were slow-paced with frequent stops to listen intently and to record.  Kroodsma’s focus was on sound. He had a small pair of binoculars with him but they were only rarely used.  He and David heard hundreds of Eastern Wood-Pewees and Western Wood-Pewees but did not see one, by serendipity, until they got to Oregon.

We travel along with the Kroodsmas on an extended field trip, never sure of what we will hear.  When Kroodsma does stop to listen, he describes amazing detail and variety in songs that most of us fail to hear. But, we can listen to those same songs and understand the detail Kroodsma discerns.

In the margins of the book, you will find QR codes (those two-dimensional bar codes). Downloading a free QR Reader onto your smartphone, iPod or tablet allows you to quickly play each vocalization that Kroodsma analyzes.  With over 371 recordings, many of which are several minutes long, you can be in the Blue Ridge Mountains of Virginia, the prairie of Kansas or in Yellowstone National Park.  If you don’t have a QR reader, you can visit ListeningToAContinentSing.com to hear the recordings.

This book provides a delightful, vicarious ride across our country. We stop frequently to appreciate the music of the birds.

Red-eyed Vireos and Philadelphia Vireos

By in Behavior, Species Accounts

Spring migration is coming to an end.  Bringing up the rear are Black-billed Cuckoos, Yellow-bellied Flycatchers, Nelson’s Sparrows and Saltmarsh Sparrows.  The north-flowing river of birds is running dry.

We see an almost synchronous arrival of a guild of songbirds collectively called the leaf-gleaning insectivores.  These birds include our vireos, warblers and tanagers.  All of them make a living by preying on caterpillars and other herbivores that attack the leaves of deciduous trees.  The leaf-gleaning herbivores are the friends of the trees, gobbling up the leaf-eating insects. A cascade of events occurs in spring allowing the warblers and vireos to return: leaf-out, followed by emergence of caterpillars, followed by the arrival of the leaf-gleaning birds.  In central and southern Maine, the first ten days of May capture the arrival of many of these birds.

Among these arrivals are Red-eyed Vireos.  I daresay that Red-eyed Vireos vie for the title of most common woodland bird in eastern North America.  A bird of treetops, Red-eyed Vireos are much more often heard than seen.

Hearing a Red-eyed Vireo is a snap because they sing vigorously all through the day.  Their song is a series of two- and three-note phrases. An effective mnemonic for learning the song is “here-I-am, where-are-you, over-here, in-the-tree”.

The song is rather monotonous and dry. Despite the seeming monotony of their song, Red-eyed Vireos show remarkable diversity in their two- and three-note phrases.  A typical Red-eyed sings around 45 phrases.  Those phrases are strung together to make a distinctive song type.  Each song type consists of the same one to five phrases.  A typical male sings about 30 song types.

A less common vireo breeding in Maine, the Philadelphia Vireo, needs to be considered in this column.  Red-eyed and Philadelphia vireos share an intriguing overlap in their song.

The Philadelphia Vireo closely resembles the Red-eyed Vireo but has a less distinct line above the eye and has a yellow wash on the underparts.  The Philadelphia Vireo is also smaller, averaging 12 grams in weight to the 17-gram weight of a typical Red-eyed Vireo.

Most nesting male songbirds defend their territories against other males of its species but not against males of other species. However, Red-eyed Vireos and Philadelphia Vireos defend their territories against their own species and against the other species.

The song of the Philadelphia Vireo is very similar to the song of the Red-eyed Vireo song.  Even highly experienced birders pass off singing Philadelphia Vireos as the more common Red-eyed Vireos.  The reason for the similarity will soon be apparent.

In northern New England forests, insect prey may become quite hard to find during the breeding season.  Because both vireos eat the same insects, there is an advantage for a territorial vireo to keep a member of its own species and members of the other vireo species away from its food sources.

In most cases, the vireos avoid direct confrontations over the boundaries of a territory.  Instead, a territorial bird proclaims his ownership of a territory by singing from perches throughout his territory.  Similarly adjacent territory owners sing throughout their territory.  The neighboring birds recognize unseen but real boundaries, avoiding physical interactions.

The problem the Philadelphia Vireo has is how to maintain exclusive ownership of a territory, defending against a larger and stronger Red-eyed Vireo that may be trying to expand his territory.  Philadelphia Vireos have solved the problem by becoming a social mimic.  These birds mimic the song of the Red-eyed Vireo.

Play-back experiments have shown that Red-eyed Vireos cannot tell the difference between a Red-eyed Vireo song and a Philadelphia song.  No wonder birders have trouble telling the two species apart by song!  On the other hand, Philadelphia Vireos can distinguish between a Philadelphia Vireo song and a Red-eyed Vireo song.

Philadelphia Vireos mimic the song of the Red-eyed Vireo to level the playing field; it’s a case of deception over brawn.

Red-bellied Woodpeckers

By in Species Accounts

In early May of this year, three readers contacted me with reports of their first Red-bellied Woodpeckers at their feeders.  This southern woodpecker has been expanding into Maine.  The species has a stronghold in our state but encountering one is no sure thing.

Red-bellied Woodpecker counts are consistent with the pattern of many invading species: two steps forward, one step back. We can see from Christmas Bird Count records that this species was a rare species on those counts from 1975 until 2003.  The number on all of those Maine counts combined vacillated between zero and ten each year. Then, a major incursion occurred in the fall of 2004.  The total on Christmas Bird Counts was 64, a spectacular increase. The counts the next three years were lower: 24, 14 and 11. The count in 2009 set a new record high with 107 Red-bellieds only to fall to 24 and 46 in 2010 and 2011. Numbers have rebounded since then with 121 sightings in 2012 and 125 in 2014.

We have been expecting this species. Christmas Bird Counts in Connecticut had 20 to 40 Red-bellied Woodpeckers until 1985 when 143 were found.  Their counts have been increasing then with slight dips in some years. The 2013 and 2014 counts yielded 1313 and 1440 woodpeckers, respectively.  Similar population dynamics occurred in Massachusetts.

Why are we seeing this northern expansion of Red-bellied Woodpeckers? This species is common in the southeastern quadrant of the United States, extending as far west as Texas, Oklahoma, Nebraska and South Dakota and as far north as central Minnesota, Wisconsin and Michigan and western New York state. Red-bellied Woodpeckers frequent humid forests, coniferous or deciduous. They adapt well to suburban environments, frequenting suet feeders, but are equally capable of persisting in deep, isolated forests.

The preference of the species for forests may be driving the northern expansion. Although we may bemoan all of the real estate development in the state, the amount of forested land is actually increasing.  This increase is largely due to the reversion of former agricultural land to woodlands.

The provision of food at bird feeders and the amelioration of the climate may be facilitating the northern expansion into Maine as well. From Breeding Bird Survey data, we know that Red-bellieds are increasing throughout most of their range, particularly at the northern limits of the range. We do not know why Red-bellied Woodpeckers are doing so well throughout their range but increases in population sizes are likely increasing competition, forcing some individuals to migrate northward in search of adequate resources.

I take great pleasure in my occasional encounter with the species in Maine.  Hearing one of these woodpeckers takes me back to my childhood in North Carolina where the distinctive kwirr or churr rolling call and the piercing cha calls were part of the pinewoods symphony. I encourage you to check out the species account at allaboutbirds.com to familiarize yourself with the vocalizations if you do not know them. Red-bellied Woodpeckers are more easily detected by sound rather than by sight. These woodpeckers are noisy creatures and their calls carry well.

With a red forehead, crown and nape, Red-bellied Woodpeckers are sometimes confused with Red-headed Woodpeckers. The entire head is red in the Red-headed Woodpecker.

Because woodpeckers are usually climbing on a vertical surface with their underbelly close to a tree, you might wonder why the Red-bellied Woodpecker is named for a feature that can’t be easily seen. The explanation stems from the fact that ornithology was once more of a museum science than a field science.  Specimens of birds are stuffed and stored on their backs in museum trays. When a museum tray of Red-bellied Woodpeckers is opened, the reddish cast to the belly feathers is easily seen.

This explanation applies to two other species whose common name is based on hard-to-see field marks: Ring-necked Duck and Yellow-bellied Sapsucker.

Northern Flickers and Yellow-bellied Sapsuckers

By in Insects, Migration, Species Accounts

The next two weeks (late April into May) will produce the peak of spring migration. Some of the migrants will pass through on their way to more northerly, even Arctic, breeding grounds and others will nest here.  A few species like Red-headed Woodpeckers and Blue Grosbeaks overshoot their intended breeding grounds and generally backtrack to where they should be.

Avian migration is largely driven by food availability. Leaf-gleaning insectivores like warblers and vireos don’t arrive back in Maine until the leaves of deciduous trees are out. Swallows and flycatchers need to delay until insects are on the wing. Birds with broader diets like Red-winged Blackbirds and Common Grackles have an easier time of it, arriving en masse in Maine in March.

Then, we have the hardy birds that scoff at the rigors of a Maine winter and grace us with their presence all year long.  Most of our woodpeckers fall into this category of resident birds. Hairy Woodpeckers and Downy Woodpeckers are common at feeders and in woodlands. Pileated Woodpeckers are fairly common birds, seen less frequently than one would expect based on their crow-size bodies and raucous vocalizations. Red-bellied Woodpeckers have been increasing in Maine over the past two decades and are now regularly seen. Our two three-toed woodpeckers, the Black-backed Woodpecker and the American Three-toed Woodpecker, are infrequently encountered.

All six of these woodpeckers make a living by extracting insect larvae from their galleries or tunnels in wood.  The powerful bill excavates a hole to gain access to the gallery and then their long harpoon-like tongue explores the gallery until resistance is fine. A quick poke and it’s time for lunch.  Perhaps you are aware of the amazing length of the tongue of a woodpecker.  It is so long that it extends behind and then across the top of the skull in a sheath just beneath the skin.  A woodpecker tongue can be three times the length of the bill.

In addition to this sextet of residents, we have two other woodpeckers in Maine that are migratory.  Each relies on food that is only available during the warmer months.

The first is the Northern Flicker.  These large woodpeckers sometimes excavate wood in search of insect larvae. However, they prefer to feed on the ground, having a particular taste for ants.  A flicker’s tongue is modified as an efficient ant-harvesting tool. It is shaped less like a harpoon and more like a brush. The many tips of the tongue effectively allow a flicker to easily harvest ants. You may see a flicker pounding on the ground.  The bird is excavating an ant colony with a particular goal of getting access to the soft, nutritious ant larvae underneath the soil surface.  Beetles make up an important part of their diet as well.

We do see Northern Flickers lingering late into the winter or even overwintering in Maine. Flickers are quite adaptable and can make ends meet by feeding on seeds and berries.

To our south, Northern Flickers may be resident birds. In Maine, the snow prevents flickers from their favored means of ground foraging in the winter.

Our other migratory woodpecker is the Yellow-bellied Sapsucker.  The name is amusing enough and its way of making a living is fascinating. These woodpeckers maintain elaborate systems of sap wells in trees.  A sapsucker creates these shallow holes and then feeds on the sap that exudes from the wells.  The sap attracts insects and sapsuckers will prey on these insects as well, particularly when feeding young. The protein-rich insects are just the ticket for growing nestlings.

A sapsucker visits its wells daily, enlarging them as necessary to insure the continued flow of sap. Ruby-throated Hummingbirds take advantage of these wells.  Hummingbirds frequently nest near sap wells and follow a sapsuckers as it works its trap line of sap wells.

Flickers and sapsuckers, it’s good to have you back for a while.

Earth Day

By in Bird Conservation, Conservation, Species Accounts

Colby College is fortunate to have a copy of the Bien edition of Audubon’s Birds of North America on loan from the Gerald Dorros family. The Bien edition was published in 1860, nine years after Audubon’s death. This edition was printed using a lithographic technique rather than the aquatint technique used in the original Havell plates. To my eye, the Bien prints are even more eye-popping than the original aquatints.

The original intent was to reproduce all 435 plates using the new lithographic process. The Civil War and hard financial times for the Audubon family put an end to the project after the first volume.

The Bien edition has some of Audubon’s most enduring and iconic plates: Greater Flamingo, Wild Turkey, Wood Duck, Common Grackle and Glossy Ibis. My favorite Audubon plate is included as well, the Carolina Parakeet.  Viewing this plate is bittersweet because the Carolina Parakeet is now extinct.

The range of Carolina Parakeets spanned Florida to southern New York along the Atlantic seaboard westward as far north as South Dakota and as far south as east Texas.  These birds were most common in the sycamore-dominated bottomlands and cypress swamps in the southeastern and midwestern states.

Carolina Parakeets were fairly large birds, reaching 13 inches in length with wingspans up to 22 inches. The body was green and the head was yellow with bright orange on the forehead and around the eyes. A spectacular bird.

Although Audubon, Alexander Wilson and other early American ornithologists provided some information on the species, no comprehensive study was ever done. As a result, we have large gaps in our understanding of the species.

We do know that the species persisted into the 1920s in Florida and probably into the 1930s in South Carolina in the vicinity of the Santee River.

Carolina Parakeets were typical parrots, gregarious and loud.  They had a broad diet like most parrots with a particular taste for cockleburs. Audubon’s plate shows these parrots feasting on cockleburs.

These birds did sometimes become a pest in orchards and grain fields. Some were shot by orchard owners and farmers.  Unfortunately, the social behavior of the species made them easy targets. Once a few had been killed, the surviving flock members would circle back to investigate the fate of their fallen flock mates and thus were easily shot themselves.

However, shooting of Carolina Parakeets was likely not a major contributor to their demise.  They were not considered a major agricultural pest.  Early settlers regarded them favorably and why not. Birds that eat sandspurs, thistle seeds and cockleburs do humans a favor. We do have some evidence that Carolina Parakeets were shot for food and for their colorful feathers. Some parakeets were also captured for the pet trade even though Carolina Parakeets were not very good mimics.

What did lead to the extinction of this species?  Three hypotheses have been proposed, each stemming indirectly from human activities. First, the loss of bottomland forests to timbering and to development reduced suitable habitat. The introduction of the honeybee (a non-native species) led to competition for nest and roost holes for the parakeets. Finally, we have some evidence that disease played a role in the species’ decline. These diseases may have come from poultry.

I look back with nostalgia on the first Earth Day on April 22, 1970. I was one of a small group at my high school that embraced the day, putting up posters in the hallways. That was the day the modern environmental movement began.

As Earth Day approaches each year, I take particular care to think about all the bird species we have lost from our direct and indirect effects. Passenger Pigeon, Dodo, Great Auk, Bachman’s Warbler, Labrador Duck, Eskimo Curlew – the list seems endless. We all need to redouble our efforts to walk more lightly on earth.

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