Teach Your Children The Right Passwords!

Teach  your  children  the  right  passwords!

~ by James J. S. Johnson

Superb Fairywren (Malurus cyaneus) Juvenile and Female ©WikiC

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.  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,  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, that they might set their hope in God, and not forget the works of God, but keep His commandments, 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).

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.  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,  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, that they might set their hope in God, and not forget the works of God, but keep His commandments, 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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Orni-Theology

Maluridae – Australasian Wrens

James J. S. Johnson’s Articles

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6 thoughts on “Teach Your Children The Right Passwords!

  1. Very interesting about the Fairy-wrens, I have never come accross this concept before in my studies. I have to say I have heard of Fairy-wrens being tricked by Channel-billed Cuckoos and have been seen trying to feed this huge bird which has had its egg planted in the nest. The poor wren is exhausted trying to satisfy the baby cuckoos huge food needs. It is unusual for Cuckoos to attampt the smaller birds nests, they stay mainly with the larger birds Ravens, Magpies and Currawongs here in Australia. The Bronze Cuckoo is smaller, and its egg more like that of the Fairy-wren. Thanks for sharing this interesting research Lee.

    Liked by 3 people

    • Sometimes brood parasitism doesn’t work out (for the home-invading parasite) because the involuntary host family doesn’t provide a diet that fits the intruder’s nutrition needs or preferences! For example, Brown-headed Cowbirds routinely fail to successfully invade American Goldfinch homes, due to the goldfinch family diet being dominated by seeds that are not the kind of protein-rich nutrition that “foster baby” cowbirds need to thrive. See Alex L. A. Middleton, “Failure of Brown-headed Cowbird Parasitism in Nests of the American Goldfinch”, JOURNAL OF FIELD ORNITHOLOGY, 62(2):200-203 (spring 1991) (“Clearly, the American Goldfinch is an unsuitable host species for the Brown-headed Cowbird”).

      Liked by 1 person

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