Tag Archives: Brown-headed Cowbird

Washington, D.C.’s Official Bird: Trouble at Home

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Washington, D.C.’s Official Bird:  Trouble at the Home Front

Dr. James J. S. Johnson

veery-thrush-nest-with-cowbird-eggs

AND IF A HOUSE BE DIVIDED AGAINST ITSELF, THAT HOUSE CANNOT STAND. MARK 3:25 

The District of Columbia’s official bird’s population faces precarious peril, nowadays, and there seems to be a “homeland security” problem. But how is that? And what is the official bird of Washington, D.C., anyway?  It’s not the Bald Eagle – that’s America’s national bird. Washington, D.C. has its own official bird.(1)

flag-WashingtonDC.blue-sky-background     GW-family.coat-of-arms

Flag of Washington, D.C., based on George Washington’s family coat-of-arms

The typical birdwatcher is well aware of his or her state’s official bird.

So if you were born in Maryland, your official state bird is the Baltimore Oriole.(2) [Regarding the Baltimore Oriole, see my “Appreciating Baltimore Orioles and my First Bird Book”, later condensed as “Attracted to Genesis by Magnets and a Bird Book”, Acts & Facts, 44(8):19 (August 2015.]

Like typical politicians of Foggy Bottom, D.C.’s official bird is an omnivore – willing to consume most of whatever is available, whether that be bugs (including their larvae), snails, salamanders, or fruits (especially those having more lipids).

Yet, also like Washington politicians, this bird is itself targeted by many predators. The adults (of D.C.’s official bird) are themselves sometimes eaten by owls and hawks that frequent deciduous wet woods.  Also, this bird’s young (i.e., eggs and hatchlings) are preyed upon by several larger birds (such as corvids, icterids, owls, and accipiter hawks), a few mammals (such as house cats, raccoons, weasels, squirrels, and chipmunks), and even some snakes.(3)

So what is the official bird of the District of Columbia? (With a name like “Columbia” you must expect it to be a dove, since “Columbia” is a form of the Latin word for “dove”.) Or you might expect, based upon the official coat-of-arms fo the George Washington family, that D.C.’s bird would be a raven.  For many years the District of Columbia had no official bird of its own.  In fact, until D.C. was granted a limited form of “home rule” (starting in AD1967), by Congress, D.C. didn’t have jurisdictional authority to designate an official bird for its domain.(1)

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Wood Thrush  (Hylocichla mustelina) ©Nhptv.org

Nevertheless, among Washingtonian birders, many unofficially adopted the Wood Thrush (Hylocichla mustelina), a rather inconspicuous passerine who vocalizes flute-like notes, brown above and mottled brown-on-white below, as D.C.’s special bird. One illustration of this came shortly after World War II, when the D.C. Audubon Society (now called the “Audubon Naturalist Society”) was incorporated; its new monthly journal was called The Wood Thrush.(1)

Finally, in January of AD1967, D.C. Commissioners (armed with new powers delegated to them by Congress) took official action, and decreed that the Wood Thrush was D.C. official home-rule bird. Then came the question:  how many Wood Thrush residents actually lived inside D.C.’s boundaries?  This question was not (and is not) easy to answer, with accuracy, because bird surveys often involve bird counters (driving cars) who pull off the road, onto the shoulder, to observe birds in wooded areas next to roads.  But D.C. has very few such shoulders (on the wood-edge roads), so mobile bird counters are handicapped from using their usual observation habits.  So the real numbers of their questionable population are estimated more by guesswork than by direct observation.

WoodThrush.nest-life-pic-AudubonSociety

Wood Thrush family at mealtime ©Audubon

Although often hidden from curious human eyes, at least the flute-like notes of these birds can often be heard in D.C.’s Rock Creek Park (a national park since AD1890!), a well-wooded deciduous forest of the nation’s capital.(1) In more ways than one, the Wood Thrush is not “out of the woods”.  In fact, its population stability is threatened by woodland habitat loss, as remaining wet woods inexorably yield to more and more “creeping” urban and suburban development.

Yet probably worse, however, the Wood Thrush population suffers from brood parasitism by Brown-headed Cowbirds – “home invaders” that intrude via false pretenses – as the brown-headed “foster children” greedily consume food intended for the nest’s “rightful heirs”, displacing the thrush nest’s rightful nestlings in the process:  “The wood thrush mistakenly protects these [home invader] eggs and feeds the [soon-hatched] cowbird young – who are larger and more aggressive, frequently causing wood thrush hatchlings to starve.”(4)

Once again, one finds a comparison with Washington’s federal politics – a failure of homeland security, a fundamental defalcation in defensive gatekeeping.(5) It’s “like déjà vu all over again”.  Maybe the precarious population of D.C.’s official bird should remind us to protect our own homes better. ><> JJSJ

References

  1. Steve Dryden, “You Might Never See D.C.’s Official Bird, But Hearing It Could Be Just Enough”, Chesapeake Bay Journal, 26(4):32-33 (June 2016).
  2. For more on the Baltimore Oriole, see my “Appreciating Baltimore Orioles and my First Bird Book”, later condensed as “Attracted to Genesis by Magnets and a Bird Book”, Acts & Facts, 44(8):19 (August 2015).
  3. See Roger Tory Peterson, Eastern Birds – A Completely New Guide to All the Birds of Eastern and Central North America, 4th ed. (Houghton Mifflin, 1980), pages 222-223 & map M273; James Coe, Eastern Birds (Golden Press, 1994), pages 114-115; Donald W. Stokes & Lillian Q. Stokes, Stokes Field Guide to Birds – Eastern Region (Little Brown & Company, 1996), page 339.
  4. Dryden, in Chesapeake Bay Journal, supra, at page 33.
  5. Regarding brood parasitism (by Brown-headed Cowbirds, African Honeyguides, Common Cuckoos, and others), see also James J. S. Johnson, “Teach Your Children the Right Passwords!”.  The phrase “keepers at home”, in the Greek text of Titus 2:5, refers to gatekeeping security, i.e., guarding the family’s home-life from dangers, not janitorial housekeeping.  (Of course, this is not to suggest that family members themselves never present dangers to a divided household – see, e.g., Micah 7:5-6; Matthew 10:35-36; Mark 3:25; Luke 11:52-53.)

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Teach Your Children The Right Passwords!

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Teach  your  children  the  right  passwords!

~ by James J. S. Johnson

Superb Fairywren (Malurus cyaneus) Juvenile and Female ©WikiC

4 We will not hide them [“them” refers to God’s prophetic words – see verses 1-3] from their children, shewing to the generation to come the praises of the Lord, and His strength, and his wonderful works that He hath done.  5 For He established a testimony in Jacob, and appointed a law in Israel, which He commanded our [fore]fathers, that they should make them known to their children,  6 that the generation to come might know them, even the children which should be born [יִוָּלֵ֑דוּ — niphâl imperfect form of the verb yâlad], who should arise and declare [וִֽיסַפְּר֥וּ — piêl imperfect form of the verb sâphar] them to their children, 7 that they might set their hope in God, and not forget the works of God, but keep His commandments, 8 and [that they] might not be as their [fore]fathers, a stubborn and rebellious generation, a generation that set not their heart aright, and whose spirit was not steadfast with God.   Psalm 78:4-8

Superb Fairywrens teach their children to use passwords, but how?

In this fallen world even bird families have troubles.

One kind of family problem, confronted by many bird parents, is the problem of “brood parasites”, which is really a sneaky kind of “home invasion”.

“Brood parasitism” is not a problem of parasitic worms or bugs.  Rather, this is a different kind of parasite – a bold “home invasion” parasite – a “foster child”, from another bird family, who was dropped into a “host” family.  The “host” family is thereafter burdened (unless and until the newcomer is evicted from the nest) with the cost of nurturing the intruding stranger who “moved in” without an invitation.  Worse, the invasive “foster child” often competes with the legitimate nestling birds for food and shelter, sometimes even competing aggressively.

PAS-Icte Brown-headed Cowbird (Molothrus ater) ©WikiC

Male Brown-headed Cowbird  (Molothrus ater) ©WikiC

One of the best-known examples of such “brood parasitism” practices is those of the Brown-headed Cowbird (Molothrus ater), an icterid (i.e., member of the blackbird family) with a head that is distinctively chocolate-brown in color.

“A small, black-bodied [and iridescent-plumed] bird, a bit larger than a House Sparrow, with a brown head and a rather finchlike bill.  Females are nondescript gray [like the hue of female grackles] with a finchlike bill.

A brood parasite, the Cowbird lays its eggs in the nests of other birds.”

A Shiny Cowbird (Molothrus bonariensis) chick being fed by a Rufous-collared Sparrow (Zonotrichia Capensis)

A Shiny Cowbird (Molothrus bonariensis) chick being fed by a Rufous-collared Sparrow (Zonotrichia Capensis)

[Quoting from Roger Tory Peterson, PETERSON FIRST GUIDE TO BIRDS: A Simplified Field Guide to the Commonest Birds of North America (Houghton Mifflin, 1986), page 102.]

But cowbirds of North America are not the only birds that abuse the (involuntary) charity care of avian “foster parents”;  cuckoos (such as the Common Cuckoo of Eurasia) are known for the same “externalizing” of their parenting costs, producing nestling competitions that result in “changeling” conflicts.

“Once a brood parasite [mother] has managed to slip her egg into a host’s nest, her reproductive role is essentially over.  She leaves each chick to fend for itself, in a [bird] family that did not choose to raise it.

There’s no reason to feel [too] sorry for the uninvited foster chick, however; it is the unwitting adoptive parents that might soon face an unexpected brutality—the ruthless slaying of all their own offspring.

Many brood parasites, such as cuckoos, immediately dispatch of their nest mates [i.e., the children of the caring bird parents who built and maintain the nest that is now compromised] as soon as they hatch by summarily tossing them over the side of the nest.  [So much for refugee gratitude!]

Brown-headed Cowbird (Molothrus ater) Egg in Eastern Phoebe Nest ©WikiC

Brown-headed Cowbird (Molothrus ater) Egg in Eastern Phoebe Nest ©WikiC

African Honeyguides use far deadlier methods to eliminate their [nest] fellows.  Equipped from birth with hooks at the tips of their mandibles, they efficiently wield these needle-sharp barbs against their defenseless nest mates.

Cowbirds do not employ such direct methods, yet they just as effectively eliminate the competition.  Their companions often die of starvation because the larger, more aggressive cowbird grabs all the food [delivered by the nestling-caring parent birds].  It is a wonder that the adults still feed the chick when they realize the disparity in size.  Yet in most cases, the adults accept it [i.e., the cowbird “foster child”], even if it appears double the size of its foster parent and requires twice the care of its [foster] siblings.

Long-tailed Paradise Whydah by Dan

Long-tailed Paradise Whydah by Dan

Not all brood parasites oust their nest mates.  Parents of the whydah family choose species that closely resemble them, such as waxbills.  Not only do the eggs match in coloration, but the chicks resemble their hosts as well.  They even have the same markings in their gaping mouths which signal hunger to an observing adult.  Whylahs blend in with their adopted families instead of destroying them.”

[Quoting from Sharon A. Cohen, BIRD NESTS (Harper Collins, 1993), page 110.]

So cowbird “parenting” is a short-lived experience, somewhat like clandestinely depositing a newborn on the front steps of an orphanage, trusting that the baby will be nurtured (successfully) by others.  But is this surreptitious forced-fostering habit a guarantee of avian reproductive success, at the populational level?

“At first, you may wonder why more birds are not parasites—after all, parasites don’t need to build a nest [for raising their babies], and once they have laid eggs there is no more to it [i.e., to parenting responsibilities on a daily basis]; but there are hidden costs [and risks] to being a [brood] parasite, mainly that the [child-abandoning] bird gives up control over its eggs and young.

Female cowbirds lay an average of forty eggs per year, but only two or three [on average] mature to adulthood.”

[Quoting from Donald Stokes & Lillian Stokes, A GUIDE TO BIRD BEHAVIOR, VOLUME II (Little Brown & Company, 1983), page 213.]

So what does this have to do with avian parents teaching “passwords” to their natural progeny? 

Superb Fairy-wren (Malurus cyaneus) by Ian

Male Superb Fairywren (Malurus cyaneus) by Ian

Consider this amazing news about the Superb Fairywren (Malurus cyaneus) of Australia, which is forced to react to the “child-abandonment” brood parasitism habits of the Horsfield’s Bronze Cuckoo. (Chrysococcyx basalis).

Horsfield's Bronze Cuckoo (Chrysococcyx basalis) by Tom Tarrant

Male Horsfield’s Bronze Cuckoo (Chrysococcyx basalis) by Tom Tarrant

The Horsfield’s Bronze Cuckoo deposits its somewhat elongated pink-white egg, with rust-colored spots, into the nest of a fairywren.  The rust-speckled egg looks like a fairywren egg, confusing the fairywren nest owners of its true biogenetic identity.  (This is an avian version of family “identity fraud!)  The fairywren’s upside-down-dome-shaped nest is often dark inside, so visual confusion about which eggs really belong there is common – hence Horsfield’s bronze cuckoos often get by with their “changeling” deceptions, recruiting fairywren parents into fostering cuckoo eggs that hatch into cuckoo nestlings.

After a dozen days of incubation, in a fairywren nest, a bronze cuckoo chick hatches – 2 days before the hatching of fairywren eggs.  The “older” nestling often ejects the fairywren eggs from the nest, displacing the rightful “heirs”.  (What kind of “refugee gratitude” is that?!)

What can fairywrens do about this parasitic (and quasi-predatory) menace?

Is there a way to avoid the involuntary “home invasion” of such Trojan horses?

Yes, there are a few defensive habits that help to protect the fairywren from such home hijackings, including:

(1) nesting in fairywren colonies – so that teamwork is employed to drive off trespassing cuckoos when cuckoos fly near the fairywrens’ nesting colony;

(2) females attend their nests with vigilance, usually, limiting the opportunities that stealthy cuckoos have to access unattended fairywren nests;

(3) when female fairywren recognize a “changeling” in the nest, prior to laying any fairywren eggs therein, the fairywren female may abandon that (cuckoo) egg and build herself a new nest elsewhere;

(4) female fairywrens “teach” their eggs vocal “passwords” to use, to prompt being fed by their mother.  It is this last habit that demonstrates communication from (fairywren) mother to child, before the chick is hatched from its egg!

A few years ago, Diane Colombelli-Négrel, Sonia Kleindorfer, and colleagues from Flinders University in Australia discovered a remarkable way one bird fights back against brood parasites. Female superb fairywrens teach their embryos a “password” while they’re still in their eggs. Each female’s incubation call contains a unique acoustic element. After they hatch, fairywren chicks incorporate this unique element into their begging calls to ask for food. Colombelli-Négrel, Kleindorfer, and colleagues showed that chicks whose begging calls most resembled their mothers’ incubation calls received more food. But the brood parasites of the fairywren, Horsfield’s bronze-cuckoos, produced begging calls that did not so closely resemble the parental password.

[Quoting  Mary Bates, “To Beat a Parasite, Birds Teach their Young a Secret Password”, posted at http://www.wired.com/2014/06/to-beat-a-parasite-birds-teach-their-young-a-secret-password/ , accessed 11-23-AD2015.]

If fairywrens observe cuckoos in the neighborhood they become more diligent in their efforts to teach the “please-feed-me” passwords to their unhatched progeny, increasing the likelihood that the babies will successfully beg for food (using the vocal “password”) when they soon become hatchling chicks.

“In a new study, Colombelli-Négrel, Kleindorfer, and colleagues again looked at the relationship between superb fairywrens and Horsfield’s bronze-cuckoos to see if a greater threat of brood parasitism would cause the fairywren to up its teaching efforts.

First, the researchers recorded calls from 17 fairywren nests in South Australia. They found the similarity between the mother’s password and the chick’s begging call was predicted by the number of incubation calls produced by the mother: If females made many incubation calls, their chicks ended up producing more similar begging calls.

Next, the researchers conducted a playback experiment at 29 nests. They broadcast either the song of Horsfield’s bronze-cuckoo or a neutral bird. After the cuckoo calls, but not after the neutral bird calls, female fairywrens made more incubation calls to their embryos. In other words, female fairywrens that heard a cuckoo near their nest increased their efforts to teach their password to their embryos.  Colombelli-Négrel and Kleindorfer say their results provide a mechanism for how fairywrens could get better at decision-making and lower the probability of committing an acceptance error for a cuckoo chick or a rejection error for one of their own chicks.  ‘When there are cuckoos in the area, you should call more to your eggs so that they have a higher call similarity after hatching and you can decide if the offspring is yours,’ Colombelli-Négrel and Kleindorfer wrote in an email. ‘We show a mechanism that starts in the nest and involves active teaching and sensorimotor learning in embryos.’”  [again quoting Mary Bates, supra]

This is truly amazing!  Anyone who is not amazed at how God programmed parenting skills into Superb Fairywrens is blind to the facts.

Also, by analogy, there may be a lesson for humans:  be careful about vulnerabilities to intrusive “foster children” that are “accepted” without informed consent  —  your own legitimate children may be put unfairly at risk.

Meanwhile, just as fairywrens teach “passwords” to their children, so should we humans.  But it is much more than “please feed me!” that we must teach our children, and our children’s children.

The vital “words of life” that we must teach, repeatedly, as the words of God, the Scriptures without which there is no real life, because mankind cannot live by physical bread alone, but by every Scriptural saying – every word that proceeds from God (Matthew 4:4).

4 We will not hide them [“them” refers to God’s prophetic words – see verses 1-3] from their children, shewing to the generation to come the praises of the Lord, and His strength, and his wonderful works that He hath done.  5 For He established a testimony in Jacob, and appointed a law in Israel, which He commanded our [fore]fathers, that they should make them known to their children,  6 that the generation to come might know them, even the children which should be born [יִוָּלֵ֑דוּ — niphâl imperfect form of the verb yâlad], who should arise and declare [וִֽיסַפְּר֥וּ — piêl imperfect form of the verb sâphar] them to their children, 7 that they might set their hope in God, and not forget the works of God, but keep His commandments, 8 and [that they] might not be as their [fore]fathers, a stubborn and rebellious generation, a generation that set not their heart aright, and whose spirit was not steadfast with God.   Psalm 78:4-8

<> JJSJ

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Maluridae – Australasian Wrens

James J. S. Johnson’s Articles

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Birdwatching at Home – December 2009

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Brown-headed Cowbird (Molothrus ater)

Brown-headed Cowbird (Molothrus ater)

December is that busy time of the year when you don’t get to do as much birdwatching as you would like to do. There are so many other things going on and then we had several days where it rained or was overcast. But, all is not lost. There is always the window to look out. Recently we increased the size of the feeding area in our small backyard and now a few birds are coming. Until this month, about all that showed up were the Mourning Doves, the Boat-tailed Grackles, our local Sandhill Crane and of course the Squirrels. In the last few weeks 11 White Ibises, 4 Palm Warblers, our Northern Mockingbird, one Yellow-headed Blackbird and three Red-winged Blackbirds and two Eurasian Collared-Doves came in to check out the feeders. A Red-shouldered Hawk scattered the birds one morning. Today and yesterday, we have had an invasion (75+) of Brown-headed Cowbirds and one Red-winged Blackbird. The problem we have is that our yard is up against a major road and it spooks the birds, so even getting the birds that most people don’t care for is a delight for us. These birds are the ones who like to empty your feeders in “no time flat”.

Consider the ravens, for they neither sow nor reap, which have neither storehouse nor barn; and God feeds them. Of how much more value are you than the birds? (Luke 12:24 NKJV)

Brown-headed Cowbirds

Brown-headed Cowbirds

What a promise to the birds and to us. God feeds them most time by the plants and bugs in the fields, but he also uses our feeders and water to supply their needs. The same is true for people who are righteous. The Bible says in Psalms 37:25-28, “I have been young, and now am old; Yet I have not seen the righteous forsaken, Nor his descendants begging bread. He is ever merciful, and lends; And his descendants are blessed. Depart from evil, and do good; And dwell forevermore. For the LORD loves justice, And does not forsake His saints; They are preserved forever, But the descendants of the wicked shall be cut off. (NKJV) The Lord helps His own by seeing they have jobs and their needs met. If times get hard and the job is gone, the Lord will lay it on someones heart to help them out. He has promised to meet our “needs” not our “wants.”