From New Scientist - Birds prefer not to play out of their league. Some female zebra finches have been found to choose low-quality males rather than their superior competitors. It’s the first time anything like this has been observed in nature.

Marie-Jeanne Holveck and Katharina Riebel of Leiden University, the Netherlands, separated zebra finch chicks into either small groups of two to three chicks or larger groups of five to six chicks. The idea is that birds that grow up in big broods have fewer resources devoted to them and will be of a lower quality: weaker, weedier and poorer singers.

Once the chicks had grown up, both low and high-quality females were placed in a cage where they could choose to listen to either a low or high-quality male song by pecking one of two red buttons. Of the 24 birds observed, every low-quality female chose the low-quality male song, and the high-quality females opted for males with high-quality songs.

Holveck and Riebel then tested how birds of the same and different quality mated. When in a cage together, birds of the same quality were much quicker to mate than mismatched birds.

Great mate

When a low-quality female did mate with a high-quality partner, her eggs were larger. The authors reckon this is because the female knows she is doing better than she deserves, and will invest more nutrients into the eggs she lays.

Zebra finches mate seasonally, so might they not have time to wait around for Mr Perfect. Mating out of their league could result in “divorce” if the male leaves for a higher-quality female.

The authors say their finding echoes a popular perception that humans choose partners who they think are as attractive as themselves, or have the same “market value”. If perceived market value can affect mate choice in such diverse species, it could be a general phenomenon, says Holveck.

“The results are striking,” says Tim Fawcett of the University of Groningen, the Netherlands. “I expect this behaviour will also be found in other animals.”

For many birds song is a strong sexual attractant and is often it’s elaboration is inversely proportional to the plumage – in finch terms think about the song of the sparrow-like wild canary compared to that of the Gouldian.  Perhaps the most famous songster is the dull looking Nightingale.  Unlike most finches these birds sing at night, with the males competing with each other for females through song (read more at Science Live).  In finches too, song is likely to be a statement of territoriality but there are many vocalisations which serve to identify species and keep flocks together or as alarm calls or juveniles attracting attention while begging for food but it can serve to attract and bond a pair.

Charles Darwin, one of the first people to promote the theory of evolution, saw that bird song and even human music were probably subjected to and elaborated by strong sexual selection and that line of research continues today.  Research published by  Huang and Hessler in October 2008 shows that male zebra finches are not just mindlessly programmed to sing to attract their mate but are rewarded in the same manner as if they were on addictive drugs!  When people take drugs like cocaine it triggers the release of the neurotransmitter dopamine in an area of the brain called the ventral tegmental region which increases our feeling of euphoria which we experience as happiness.  This same neural pathway is triggered when a male zebra finch sings to his mate, however as Hessler explained to New Scientist magazine we can’t know if it actually makes the bird happy but it’s a good bet that it does. 

As mentioned earlier birds have a range of vocalisation which are generally species specific, so how does a bird know what to sing?  Certainly some birds do learn song or modify song by reproducing the sounds of their own environment or even stealing them from other species.  There are many examples of mimics from many bird families around the world such as the hill mynah here in Asia, the Australian lyre bird, the north American mockingbird, the African gray parrot and the European hooded crow.  In birds with fairly fixed songs, some degree of modification is desirable since birds carrying the learning trait are able to modify their song to become even more attractive or to denote kinship which serves to make these lines more successful.  In aviculture this process can go awry.  Birds fostered to another species  often become imprinted with the song of their foster parents and this has the effect of decreasing their reproductive success because of the visual and auditory confusion this causes to both species.  Preference for the wrong species will often be accompanied by a decrease in fitness or sterility in of hybrid young.  For this reason it is important to remove interspecific fostered birds from their parents as soon as possible and leave them with their own kind.

In zebra finches again it has been discovered that they have a genetically programmed and hard-wired version of their own song in their brains which they compare to the sounds they produce and then alter the song to match the model song they carry (read more at BBC.1C ). This learning process even occurs when they are asleep (details BBC.2C). How the brain responds and learns in birds is very different to our own.  When learning news songs each spring canaries actually grow new brain cells (listen to or read the BBC.3C transcript) whereas in adult mammals brain cells do not grow although they do forge new connections via dendrite growth.   In zebra finches breeding is opportunistic and so they don’t experience the annual growth and decline of brain tissue that is seen in canaries but instead new neurons  continuously differentiate from the brains own stem cells and this is of course of great interest to doctors seeking to repair degenerative brain diseases in humans (read more at BBC.4).

Birds usually produce sound with a voice-box but the structure and location of the avian syrinx is different to that of the mammalian larynx (read more at Hear Birds).  Just producing song is a miracle in itself requiring the use of some of the fastest contracting muscles known to exist (see NBC story). A zebra finch’s syrinx (vice box) muscles are capable of contracting and relaxing in just 3-4 milliseconds or about 100 times faster than we can blink. 

If anyone wants to read more about bird-song then there’s a comprehensive atricle on Wikipedia that’s worth reading. For those that do have an appreciation of bird-song that goes beyond my utilitarian view then you may want to try listening to the collection on Tony Phillip’s site.

In this video, you’d also hear the nestlings crying for the food, which the father adeptly provides. The father first unhusks the seeds and “eat” them, and regurgitates them to its babies’ mouth. Just this morning, I saw Juday, the mother, do this exact same thing outsideof the nest, giving me a complete view of how it was done. First, the parents would come near the chicks and tap their beaks. The chicks would respond by opening their beaks, almost automatically, and the parents will put their beaks inside and basing from the movement of their necks, regurgitates the food that they have swallowed a few minutes ago. The whole process lasts for less than 5 seconds, and would preoccupy the parents all throughout the day.

 I looked at the first clutch after two weeks of no hatching and both of the eggs were cracked.  They didn’t smell bad for some reason, but I know from this article which I’ve read before that cracked eggs do not hatch.  If only I had the initiative to check them early.  Here’s a quote from zebrafinch.co.uk.

If the egg is cracked it is no longer good and you have a ‘bad egg’ on your hands. Just dispose of it. If not, lay the egg back in the nest gently and the parents should have no problem with it.

This time I plan to check their eggs after seven days of sitting. It has been three days already since the female sat on them 3 eggs, and I’m making a scratch paper out of our calendar to track the progress. Basically, knowing that your finches’ eggs are bad at the early stages saves the pairs trouble on trying to sit on them to no avail. Para hindi ma-stress ang nga ibon, ika nga.

I’m just a little surprised the zebras didn’t know they were sitting on duds. I’ve been to Sir Emer’s place in QC and saw gouldians throw their eggs out, and according to Sir Emer, the gouldians know when they have a bad egg. Ms. ladybird, ito rin po ba yung karanasan nyo sa gouldians nyo? I’m not sure about canaries, maybe Sir Albert “the warlock” can enlighten us. And seona, I know you have so many pairs. Do you check all of their eggs or you just wait it out ’til they don’t hatch to throw them away.

Sana magkwento kayo ng mga karanasan nyo sa mga basag at bugok na itlog ng inyong mga ibon.

Here, we studied within- and between-sex patterns of food intake and plasma pigment circulation in the Zebra Finch (Taeniopygia guttata) to assess how sexually dichromatic, carotenoid-based bill pigmentation serves as an indicator of pigment access in the diet and carotenoid transport through the bloodstream. First, in a food-choice study, we found that males and females did not consume different types or amounts of food, despite dramatic sex differences in bill coloration. Similarly, variability in carotenoid-based bill pigmentation within each sex was uncoupled from levels of food consumption. Next, we used high-performance liquid-chromatography (HPLC) to quantify the types and amounts of carotenoids circulating through blood. Male and female Zebra Finches circulated the same four major carotenoid pigments in blood plasma (lutein, zeaxanthin, anhydrolutein, and cryptoxanthin), but males circulated a significantlyhigher concentration of plasma carotenoids than did females. Within both sexes, individuals thatcirculated more carotenoid pigments displayed more brightly colored bills. In sum, these resultssuggest that physiological factors such as pigment transport may play a more important role inshaping variability in carotenoid-based bill coloration in this species than does diet. Future studiesshould be aimed at identifying the proximate determinants of plasma carotenoid circulationin these birds as well as how circulated pigments are used to produce maximum color displays.

You may download the research article here. I am thinking we can apply the same concept to our gouldians and canaries.

What could this mean to our hobby?  For ages, breeders have been pairing birds to produce color variations.  This is specially true for gouldians and zebras, of which we usually ignore the quality of the male’s song.  For canaries however, it is usual that the juvenile will get its song from other canaries, primarily the father.  Some canaries are therefore bred because of the duration and quality of their songs.  It is therefore easier to choose to breed better singers in canaries, as studies have proven that they are actually more intelligent than the rest. 

 Here’s an excerpt from that report:

Why do females of some avian species choose suitors with the most elaborate courtship songs?

Simple: Fancy singers have more elaborate brain structures (to learn singing and other life skills), brains that the females hope their offspring will inherit.

Reports linking sexual selection on the basis of song and the “heritability” of bigger brain structures in three different bird species – European sedge warblers, cowbirds and zebra finches – were published this year by Cornell scientists.

While the Cornell scientists hesitate to extend their avian neuroscience discoveries to the evolution and amorous affairs of homo sapiens, the leader of the studies says it helps to think in human motivational terms.

“An elaborate bird song is like a Grand Cherokee in the driveway or an M.D. after the name – a kind of shorthand for all the desirable qualities that a female wants in a mate and wants passed along to the children,” said Timoth DeVoogd, professor of psychology and neurobiology and behavior at Cornell. “Of course these birds are not scholars of evolutionary theory. They don’t think Darwin’s principle of sexual selection when they make up their minds about which male sings best.

“Nevertheless, their choices will have an immediate impact on the success of their parenting and, in a longer-term, evolutionary sense, on the success and survivability of their kin for generations to come.”

So, when are you going to start breeding those singers?

According to this post on NFSS.org, there is even a distinction between what is a black-faced mutation.  To quote from the article:

Australian breeders distinguish between two forms of the Black- faced mutation: One is called Black Face and is identical with the European Black Face with the exception that the black breast/belly color should stop between the legs. The other is called Black Bodied.

On a Black Bodied, the breast bar is not only extended downwards all the way to the tail, but also upwards to the lower beak. In addition Black Bodied males do not have the characteristic flank spots, but in stead completely orange flanks. European breeders have chosen to only accept one standard and instead use combinations with the Black Breasted mutation to increase the black area below the beak, but since the Black Breasted mutation is not available in Australia, this is not an option for the Australians.

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Another question I have for you guys is: is beauty synonymous with rarity? And to push it even further–is an all black really worth all your time and money?

Thanks for watching.