Summer Bird Identification Quiz

Although many North American bird species completed their spring migration months ago, some are just now beginning to set up territories and nest on their breeding grounds.  With that in mind, I present another short identification quiz for the summer months!

1.  This species may be seen migrating late, and some individuals linger in areas outside of the breeding range.

2.  Look for this species in woodlands, especially near water.

3.  The species in this photo is also a bird of woodlands.

4.  In the photo, one of the clues to this bird's identity is hidden.

Answers:

1.  The American White Pelican is widespread across much of North America, and its winter range extends as far south as Central America.  It migrates across wide swaths of North America and breeds in several locations west of the Mississippi River.  Some nonbreeding individuals remain on lakes and other large bodies of water in the eastern portions of the U.S.  Unlike the coastal Brown Pelican, the American White Pelican does not dive for its prey, but instead forages for fish near the surface.  Groups will work together to more efficiently pursue their prey.

2.  Unsurprisingly, a significant clue here is the yellow throat!  Yellow-throated Warblers are far from the only wood warblers with this field mark, however.  For example, there is the widespread Common Yellowthroat, a species of thickets and marshes.  The western Grace's Warbler has even more similar features to the Yellow-throated Warbler: a gray back, white wing bars, black streaks on the sides, and a yellow throat.  The Yellow-throated Warbler's black mask and white eyebrows, though, are distinctive.  

Yellow-throated Warblers will sometimes conceal their nests in the Spanish moss that frequently grows in the wet, wooded habitats that they prefer.

3.  While the widespread and familiar Red-tailed Hawk is commonly found in more open environments, the Red-shouldered Hawk is adapted to woodlands.  The juvenile Red-shouldered Hawk in the photo lacks the rust-colored feathers of its parents, but its moderately slim build (compared to that of the stockier Red-tailed Hawk), banded tail, and streaked breast and belly help clinch the identification.  The Red-shouldered Hawk also lacks the pale "V" marking that can be seen on the back of a perched Red-tail.  

Because they tend to frequent swampy forests, Red-shouldered Hawks feed on a variety of animals, including frogs, snakes, and lizards.

4.  One clue may be hidden, but the white-spotted underside of the tail, the rust-colored wing feathers, and the pale underparts all point to this being a Yellow-billed Cuckoo.  The yellow mandible would be another useful field mark in regions where the Black-billed Cuckoo also occurs.  Cuckoos use their thick bills to catch hairy caterpillars, among other prey items, and tent caterpillar outbreaks may provide excellent conditions for viewing these usually secretive birds.  Unlike the Common Cuckoo, which breeds in Europe and Asia, North American cuckoo species only rarely practice brood parasitism, preferring to build their own nests and raise their own young.  

Swainson's Warblers

My first “sighting” of a Swainson’s Warbler wasn’t really a sighting at all.  I was birding one of the local sewage treatment ponds with my then-mentor, and I heard an unusual song coming from the woods behind us.  My birding mentor identified it, but to try to find the singer in the dense, swampy woods would have been futile.  I didn’t encounter another Swainson’s Warbler until the fall of that year, when one showed up in a thicket behind my house, walking around in the leaves less than five feet in front of me.  After this, I was able to hear, and occasionally glimpse, Swainson’s Warblers many times during the spring and summer.  This elusive bird, once practically unknown to me, was present in a surprising number of places.

The Swainson’s Warbler is very local and difficult to see but is not an exceptionally rare bird over much of its breeding range in the southern United States.  It does have the distinction of being elusive enough to escape detection by ornithologists searching for it for decades.  Two of the most famous cases of “lost” avian species, the Ivory-billed Woodpecker and the Bachman’s Warbler, also had a history of being spotted once, then suddenly disappearing, not to be seen again for years.  These species are legendary for their secretiveness, but the Swainson’s Warbler also had a long history of disappearance and then rediscovery, before regular studies confirmed many facts about its once little-known lifestyle. 

The drab appearance of this diminutive creature seems to point to one reason it was overlooked for so long.  At first glance, the Swainson’s Warbler does seem unremarkable, especially when compared with other North American wood-warblers.  A small bird, but large for a warbler, the Swainson’s Warbler measures about five and a half inches from beak tip to the end of its short, slightly notched tail.  The bill, in fact, is different from that of most other warblers in being relatively long and sharply pointed.  The bird’s upperparts are grayish-brown, a dead-leaf color that serves as an effective camouflage.  As counter shading, the underside of the bird is a pale gray or whitish shade, but some individuals show a tinge of yellow in this area.  The crown of the Swainson’s Warbler is a warm shade of brown, making it look nearly chestnut next to the extremely drab upperparts.  The bird also has a faint eye-line on the grayish face, and its head is very flat at the forehead.  The warbler’s long, pink legs provide a clue to its lifestyle; it spends much of its time walking on the ground—an unusual behavior for a warbler—as it forages for invertebrates in thick leaf litter.

These features reveal much about the habitat of the Swainson’s Warbler, and in fact the real difficulty ornithologists had in studying this bird was the impenetrability of this habitat.  The Swainson’s Warbler prefers dense, swampy woodlands with thick undergrowth and a sparse ground cover, leaving the forest floor open to falling leaves and creating the slowly-decaying microhabitat that many species of invertebrates use.  Although it is not absolutely necessary, cane is often a component of this habitat; where stands of cane are present, the warblers build their nests in them near the ground.  Other stiff understory plants such as palmetto are, of course, also used to support nests.  In the northern areas of its range, parts of the Appalachian Mountains, the Swainson’s Warbler retreats into a very different habitat: mountain laurel and rhododendron are the usual understory plants in these ecosystems. 

Regardless of the plants making up the forest undergrowth in Swainson’s Warbler territory, the bird is extremely difficult to locate.  One of the few clues to its presence is its song, a loud, clear Whew whew whew whip-poor-will that falls in pitch, rising again at the last note.  The song is similar to that of the Louisiana Waterthrush, but the waterthrush’s song ends with a jumble of short trills and sharp notes, rather than the clear, ringing notes at the end of the Swainson’s Warbler’s.  The song may be loud for a tiny bird, but the singer is extremely hard to see.  It nearly always chooses a secluded perch somewhere in the upper mid-story level of the woods.  If the bird senses that it has been detected, it flies quickly to a new perch and sits there silently for several minutes until “danger” has passed, often to the chagrin of a birder wishing to see it!  I once tried to creep up on a singing Swainson’s Warbler, and the best view I got was of the bird’s tail end as the bird—having detected me—darted into a cane thicket.  But during migration, even normally shy birds like the Swainson's Warbler can be seen feeding out in the open, far from dense cover, when songbirds of all species engage in atypical behavior in order to exploit more food sources.

Swainson's Warbler -- pen and ink

If the Swainson’s Warbler is easy to overlook now, over a century ago it was barely known to exist.  The habits of the Swainson’s Warbler helped to keep its most basic life functions secret for decades; discovered by Alexander Wilson in 1832 and described by John James Audubon in 1834, it was nearly unknown and wasn’t reported again until William Brewster and Arthur T. Wayne, two pioneering American ornithologists, found it in South Carolina in 1884.  Unfortunately, after this discovery, the species was again unstudied for many years.  Among other things, these naturalists documented its nest for the very first time.  Since the 1930s, however, when birding became popular, we have learned much about this warbler.

One of the crucial details of the bird's life history—its nesting behavior—was first documented by Brewster and Wayne.  The female Swainson’s Warbler constructs the nest, a somewhat messy, bulky cup composed of twigs, leaves, and vine tendrils.  It is lined with a wide variety of materials, including grass, mosses, bark, and hair, and is usually built only a few feet up in the vegetation.  The eggs are an unmarked white—probably an adaptation to the secluded nature of the nest site.  Most birds with well-concealed nests have pale eggs, since the eggs themselves don’t need camouflage.  This is very common in cavity-nesting birds, and the nest of the Swainson’s Warbler is so well hidden that it almost functions as a cavity—it could pass for just a clump of dead leaves if seen by a casual observer.  The female seldom leaves the nest during the incubation period; she alone hatches the eggs, which takes 13 to 15 days.  Both parents tend the helpless, altricial young until they fledge, ten to twelve days after hatching.  Apparently the chicks are fed on the same kinds of insect larvae, spiders, and millipedes that constitute the adults’ diet.  The long, pointed beaks of the warblers enable them to probe the crevices of dead leaves and even the top layer of forest soil for their prey.  As they shuffle around on the forest floor, they will even flip dead leaves over with their bills to inspect the undersides, causing a slight rustling sound similar to that made by other southeastern forest species, such as the Eastern Towhee. 

Although the Swainson’s Warbler is an uncommon and fairly local species in most of its range, exceptionally good breeding habitat can support far more than the usual number of nesting pairs; up to 44 singing males have been reported in some areas.  The Swainson’s Warbler is, unfortunately, facing many of the same problems that are contributing to the decline of other Neotropical birds.  Because it generally prefers dense woodlands with canebrakes, it is losing habitat on both its breeding grounds and its wintering grounds in the Bahamas, Cuba, Jamaica, Mexico, and Belize.  The unique Appalachian population, which some scientists believe to be a distinct subspecies, has declined precipitously.  In areas where its habitat is badly fragmented, the Swainson’s Warbler is also susceptible to brood parasitism by cowbirds.  Due to these factors, the National Audubon Society has placed the Swainson’s Warbler on its WatchList as a species of global conservation concern.

It’s amazing to think of the millions of years that helped shape the unique behaviors and adaptations of this unusual little bird.  Though we now know a great deal about its habits and place in the ecology of the forest, it took well over a century to discover them, and there are still secrets that it has yet to relinquish. The mysteries behind animals such as the Swainson’s Warbler are constant reminders of how much more there is still to learn about the natural world around us.

References:

Audubon WatchList 2007, National Audubon Society.  http://www.audubon.org/news/audubon-watchlist-2007.

A Field Guide to Warblers of North America.  Dunn, John, and Garrett, Kimball.  Houghton Mifflin, Boston and New York.  1997.

A Field Guide to the Birds’ Nests.  Harrison, Hal H.  Houghton Mifflin, Boston and New York.  1975.

Birds of Mississippi.  Turcotte, William H., and Watts, David L.  University Press of Mississippi, Jackson.  Mississippi Department of Wildlife, Fisheries and Parks.  1999.

The Cornell Lab of Ornithology’s Guide to Birds of North America, version 3.  2001.

The Summer Redbird

While the Northern Cardinal is the most familiar “redbird” in southeastern North America, the region hosts another rosy-plumaged songbird species that is also quite common, if somewhat more secretive: the Summer Tanager.  Catching a glimpse of one of these migratory birds may be difficult at times, but, if you learn to recognize their vocalizations, you may find them in a lot of places that you might not have expected.  The main call of this species is a dry pik-i-tuk-tuk, while the song is a slurred, throaty warble—smoother than the more separated phrases of the American Robin.  Because Summer Tanagers—and most tanager species, in general—tend to forage in the middle and upper branches of trees, seldom venturing close to the ground, the sounds that they make really are the most obvious signs of their presence in a given area.  Mixed forests, particularly pine-oak woods, are the preferred habitats for this species.

If you do manage to spot a Summer Tanager after hearing its song or call, it’s generally pretty easy to tell whether the bird is male or female.  Fully adult males have rose-red feathers all over.  Adult females are more variable, and can be anywhere from a slightly greenish yellow to an orange-yellow with hints of red.  

Adult male Summer Tanager

Female Summer Tanager

Notice that I said it’s generally pretty easy to tell the sexes apart.  Identification becomes slightly more complicated in the fall, when first-year males can have smatterings of red in their plumage or even an overall orangey appearance, just like female tanagers.  However, the young males usually have more red on the undertail coverts than the adult females do, so it’s sometimes possible to tell them apart.  Additionally, although some first-year female Summer Tanagers may look almost identical to some adult females, it’s more typical for them to be a bit drabber in color.  At any rate, studying the variety of tanager plumages during the autumn season can be an interesting project!  And, when spring rolls around and the tanagers return from their wintering grounds in Mexico, Central America, and the northern portion of South America, most of the young males will have plumage in a patchwork of red and yellow, as in the photos below.  It takes another year for their yellow feathers to be completely replaced with red. 

Preening immature male Summer Tanager

 

Immature male Summer Tanager

Summer Tanagers feed mainly on insects and fruit, and this is evident from the shape of their bills, which are stouter than those of exclusively insectivorous species, but slimmer than those of seed-eaters.  Actually, most people should probably be thrilled to have tanagers around, since the birds’ favorite insects to consume are bees, wasps, and hornets!  One of my earliest Summer Tanager sightings was of an adult male casually catching paper wasps high in a sweet gum tree in my backyard, and I’ve witnessed countless other tanager and hymenopteran interactions since then.  If there isn’t too much ambient noise, then you can sometimes even hear the *SNAP* of a tanager’s bill as it closes on the bee or wasp.  The tanager will then sometimes vigorously rub its prey against a tree branch before swallowing it whole and, later, regurgitating the tough, indigestible bits of insect exoskeleton.  Yep, hawks and owls aren’t the only birds to produce pellets; most species do.

I have never seen an active Summer Tanager nest—perhaps surprisingly, considering how interested I am in birds’ nesting habits.  However, monitoring a nest if I found one would probably not be too difficult, since tanagers prefer building on branches over open spaces and gaps in the woods.  There would be minimal vegetation in the way!  The usual number of eggs for the species is three to four, which are laid in a cup-shaped nest of grasses and leaves.  Females do the incubating, but both parents feed the young throughout the nestling stage and for at least a few weeks after the fledging.  Because Summer Tanagers are Neotropical migratory birds, developing survival skills during their first summer and autumn is crucial; after all, they don’t get any do-overs during that first grueling and hazardous journey to the wintering grounds.  If they make it back to the breeding grounds in the spring, then they can start to claim nesting territories for themselves, continuing the cycle.

Although summer is nearly over, there are still plenty of opportunities to see Summer Tanagers in their breeding range before they depart around mid-October.  Listen for the calls, watch for the wasp-catching behavior, observe the varied plumage patterns, and just enjoy the presence of our other “redbird.”

Source:

Robinson, W. D. (2020). Summer Tanager (Piranga rubra), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.sumtan.01

The Blue-headed Vireo: A Winter Songbird

In only a short time, the woods will be filled with the color and song of newly-arrived migrants: warblers, gnatcatchers, tanagers, and vireos, among others.  The Yellow-throated Vireo is one of our earliest migrants, and Red-eyed and White-eyed Vireos are some of the most numerous spring and summer forest birds, but even in the late days of winter there is a species of vireo living secretively in woods of the Southeast: the Blue-headed Vireo.

Blue-headed Vireos are hardy winter residents in the southern states.  They can be found in both upland and lowland habitats, in mixed or coniferous forests, where they feed on insects gleaned from bark, and also a few small fruits.  Like most vireos, they have a loud, scolding call, and their song is a series of short, whistled phrases.  Although they are usually silent in the winter, on warm days they can sometimes be heard singing.

The Blue-headed Vireo was originally grouped with two other species, the Plumbeous and Cassin’s Vireos—both of which occur in western North America—as one species, the Solitary Vireo.  It may be not be used anymore, but this name is still descriptive; outside of the breeding season, Blue-headed Vireos are rarely seen with other members of their species, preferring instead to forage with chickadees, titmice, warblers, and kinglets.  In fact, one of the best ways to locate one is to search through these flocks of small, jittery songbirds, until the slower, more deliberate movements of this reclusive bird catch your eye.

Once you find a Blue-headed Vireo, take the time to appreciate the colors of its plumage.  The namesake bluish-gray head contrasts with the bold white “spectacle” marks around the bird’s eyes.  The back is bright olive, and the wings have prominent yellowish wing bars.  The underparts are white, with yellow flanks.  The heavy, slightly hooked bill is very different from the thin, almost straight bills of the warblers and kinglets that the vireo feeds with.

This songbird arrives for the winter in October and departs for more northerly regions in mid-April.  Be sure to get out into the field to spot the colorful Blue-headed Vireo and other wintering songbirds!

Winter Frogwatching

If you live in the southeastern U.S., you’re probably used to the discrepancy between the timing of the seasonal changes that you observe and the "official" dates on your calendar.  During the winter, temperatures often climb to the 80s; brightly-colored flowers dot the lawns; resident birds start to seek out nesting territories in the woods and fields; and snakes, turtles, and (in some areas) alligators begin to stir in lakes and ponds.  Breeding frogs, taking advantage of the rain and the warmer temperatures, also put in appearances during this period.  While many frog species in the southeastern states hibernate through the winter and are not active until March or April, a few are commonly heard calling before the trees leaf out.  If you live in Mississippi, the species that you are most likely to encounter during the winter are chorus frogs, members of the Pseudacris genus.

The spring peeper (Pseudacris crucifer) is probably the most abundant of these “winter” chorus frogs.  I would venture to say that most people in the southeast are very familiar with the piping call of this tiny amphibian, but for those who aren’t (or those who would like a refresher), the U.S. Geological Survey has a recording.  From around late January to early April in Mississippi, you might hear this distinctive call in almost any wooded habitat near water.  Spring peepers spend much of their time in dense vegetation near the ground, so they are difficult to see—beneficial for them, but a pity for us, because they have very pretty, if subtle, patterns: dark brown leg stripes and a dark-brown x-shaped marking on a lighter brown background.  The camouflaging coloration and retiring habits are useful predator-evasion adaptations.

A close relative of the spring peeper, the upland chorus frog (Pseudacris feriarum) is fairly common in winter.  Despite their name, upland chorus frogs can be found in both lowland and upland habitats.  I would suggest listening for them in areas that are more open than the typical spring peeper habitat; old pastureland, fields, and meadows near sources of water are good places to check.  The trilling call of the upland chorus frog somewhat resembles the sound made when you run your thumb over the teeth of a metal comb.  In Mississippi, I have heard this species as early as the middle of December, and it may breed until April.  Like spring peepers, upland chorus frogs are secretive and extremely hard to spot.  One of their diagnostic field marks is a pale stripe above the upper lip, just below the dark stripe that extends behind the eye.  

Upland chorus frog - mixed-media painting

It’s worth pointing out that, in recent years, the range limits of the upland chorus frog and the very similar Cajun chorus frog (Pseudacris fouquettei) have been reevaluated.  Both species are found in Mississippi, but it’s likely that the Cajun chorus frog is restricted to the western portion of the state, while the upland chorus frog occurs farther east.  The call of the Cajun chorus frog is slightly slower than that of the upland.  

Happy listening!


Sources

The IUCN Red List of Threatened Species, http://www.iucnredlist.org/
USGS Frog Quiz, https://www.pwrc.usgs.gov/frogquiz/index.cfm?fuseaction=main.lookup