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canario timbrado

Song Learning in the Canary I

   
 

By Vicente Jerez Gomez Coronado
Translated from the Spanish by Sebastian Vallelunga


INTRODUCTION

The object in breeding champion song canaries has two fundamental aspects: the first consists in obtaining canaries with an adequate genotype, which means we must begin with parents of definite genotype themselves, derived from lines which were well established previously, using a process of correct pairing and selection, but once one is using the preceding process, it is necessary to implement an adequate program of song apprenticeship among young males, which enables these already young adults to, with a selected timbre of voice and notable aptitude, interpret a new and worthy song score. The knowledge that Timbrado "canariculturalists" have about this learning stage is fundamentally empirical, based on the experiments of breeders who have a diligent dedication to the birds. In essence, this knowledge is founded, in my view, in a fact accepted by all, that canaries inherit the timbre and other faculties of the voice from their progenitors; and this leads to two counterposed hypotheses: it is said that the song, with more or less richness of syllables and concrete musical norms, must be a spontaneous manifestation of genetic endowment in conjunction with the influence of the surrounding environment, while others maintain that for a song to be of high quality, it must be learned and imitated from adult examples who are their neighbors during the learning stage. The first group uses no tutors so that the song will be, as we have said, a manifestation of the genes and not of an apprenticeship, the lessons of which could be lost the following year; the second group have their young birds live near adult examples who can teach them to sing a predetermined song with perfection.

It also seems accepted by all canariculturalists that the canary learns his song during a period that runs from birth until the month of November, and after this learning period the song "locks" and a stable song is presented. Normally, in the middle or at the end of October, the young birds are separated from their brothers and are individually caged to be listened to by the breeder, either grouped into a team or left as individuals, and trained for presentation at song contests which are held from November to January. The training consists, in essence, in keeping them in an enclosure with little light and moving them, periodically and for a short duration, to an illuminated site so they will become accustomed to singing when in the light and so to perform at the moment they are being evaluated by the judge. With some frequency, the breeders administer testosterone in the form of drops during the training period. Also with some frequency, shows are being conducted earlier, starting at the end of October to the middle of November, obliging the contestants to individually cage the birds earlier than was stated above, even as early as mid-August to mid-September, which could certainly alter the natural process of learning.

It is known that periodically, that is, once each year during the molt, sometime in the months of summer and fall, the canary stops singing with mastery in order to recuperate and to renew his song; by winter the song can be the same as that before the molt or, more or less, different from it. In relation to this same point, there also exist a difference of opinion on its significance such that those who use tutors say that if their birds do not modify their songs in successive years it is because they have heard an adult model of quality in their youths, while those who don't use tutors attribute it to the idea that the song of their canaries is a spontaneous expression of their genes, nothing learned apart from their genetic endowment.

In the present article I seek to review and systematize the empirical knowledge employed in the song learning of our canaries. The method employed has been presented to breeders of different tendencies, accredited by means of their wide experience, for their input, and the written sources consulted were found in the MEDLINE database of the US National Library of Medicine. This article will unfold as follows: phases, hormonal control and learning, imitation of adult models, and conclusions.


PHASES OF LEARNING

It would serve us well, before entering into the polemics which follow, to review the existing studies on the form in which canaries learn to sing their song with dexterity from birth until the adult stage.

Birds sing in order to communicate with others, establish breeding territory, and, in the case of males, to attract their mates.

Since antiquity it has been recognized that certain birds possess the capacity to imitate sounds; nevertheless, it was W. H. Torpes who, in the 50's, demonstrated that songbirds exercise this capacity habitually, and that they have the capacity to learn to sing in a form similar to the way that humans learn to talk: imitating the models provided by adults. He observed that the pinzones learned to sing from adult models at a single stage of their lives, before achieving their sexual maturity; afterwards they lost this capacity to learn for good. This period in which learning could take place he called the "critical period" in learning. It did not, however, happen in the same way for canaries since these change their song from year to year and are, thus, "time-unlimited" learners. Each year they have their "critical period" of learning before the coming of spring: during late autumn and winter.

The song of canaries evolves from birth until sexual maturity, passing through various phases:

  1. The first sounds which a canary emits, between birth and complete independence from his parents at the end of the fourth week, are shrill cries that move his parents to feed him.
  2. The first rudimentary attempts at song begin in the fifth week and last until the second month of life; these attempts are called "subsong". They are of low volume and variable structure, and are emitted when the bird is almost dozing: the bird is said to be "reviewing his lessons" by breeders. They seem to represent time periods and phases of vocal practice, from which eventually originates the complete song repertoire which will be used in communication.
  3. A more structured song, very near to adult song but retaining much variability, is the area of "plastic song"; it lasts about six months: from the beginning of the third month of life until it achieves sexual maturity, at seven or eight months. As we will see later, during the first half of the plastic song stage, the size of the cerebral centers that control song increase only a little, but, during the second half ( from the sixth to the eighth month of life), there is a spectacular increase in the size of the superior vocal center. In the last part of this phase, the canary can already vocalize 90% of the syllables that he will use as an adult.
  4. At the beginning of the first breeding season, the canary has transformed the syllables produced into stereotypical sound and expresses a "stable song" with a richness of concrete syllables and following fixed and typical musical norms: the "locking of the song" according to breeders. It does not seem easy to achieve the consolidation of "stable song", if we consider the many months of practice: the time of "plastic song".
  5. Without doubt, this song is not the song or definitive syllabic repertoire which will be sung for the whole life of the canary. Every year after the mating season, during the end of summer and autumn, the bird looses his learned mastery of song execution and this is exchanged for another period of instability of song, just like the "plastic song" of the young. During this period there will be dominant syllables which will be forgotten, while at the same time new ones are incorporated into a new stable song, which will be expressed in the following spring; thus, the adult male canaries can unfold a repertoire of new syllables in their songs. The transition from stable song to plastic and back again to stable, is repeated annually in the adult canary.

 

HORMONAL CONTROL IN LEARNING

There are many environmental factors that can influence song learning in canaries, like heard sounds, the light intensity of the site they are in, the food eaten, the company of other canaries, adults or young, and probably other unrecognized factors as well. Moreover, this seasonal learning is controlled by hormonal balance; the phases of new syllable acquisition are preceded by lower concentrations of blood testosterone, the male sex hormone. Effectively, the canary's song is characterized by the number of sounds or distinct syllables it contains and by certain musical norms; when the canary is in the plastic song phase, it may incorporate new syllables into its song. This incorporation coincides with the augmentation of the cerebral center which controls song, and is preceded by a fall in blood testosterone levels; conversely when blood testosterone levels are high the canary is found to be in the stable song phase, adding few syllables to its song.

One may affirm, also, that the plastic song phase, which goes from the beginning of the third to the end of the seventh or eighth month of life, from approximately May to November, is the "critical period" of learning among canaries, above all, during the months of August, September, and October. During this time canaries prepare by means of a natural capacity for learning for learning syllables and musical norms, more so than at other months of the year.

From that which was affirmed by the preceding paragraph, one may deduce that if we shorten the duration of the critical period of learning or plastic song phase, the canary would have less time to learn new syllables and consequently develop a stable song with a "poverty of syllables". If we give exogenous testosterone to canaries during the period from the third to seventh month, approximately from May to October, and raise the level in the blood to the level reached in November, we can accelerate the sexual maturation, attaining the stable song phase earlier, but this happens at the expense of learning, with a shortened duration of the critical period. Also, proceeding to the individual caging of the male birds when very young, like the middle of August or middle of September, can accelerate their sexual maturation, again shortening the critical period. These two processes, giving exogenous testosterone and early individual caging of the young, put one on a par with those breeders who are obliged to present their canaries at song contests when quite young, like the end of October or the beginning of November. But, in addition to shortening the duration of the critical period, early caging or addition of excess testosterone can counteract the capacity for learning during the most productive months of this period which are from August to October when the most syllables may be learned by the canaries. As can be seen, the convocation of early song contests can promote syllabic poverty in the songs of those canaries which participate in them. Moreover, we must be aware that the early individual caging of the young canaries creates a situation where learning at this time is realized solitarily, while those caged at the normal time, from mid-October to mid-November, have their learning period enriched with the company of other male canaries; and in the same way holding very young birds in the dark may alter the process of learning qualitatively. Nevertheless, one may hypothesize that, if one gives exogenous testosterone during the plastic song phase (solely with the objective of restoring fallen levels of this hormone), we will avoid possible deficits during the plastic song months and perhaps stimulate the growth of the superior vocal center and the nucleus of the archistriatum which will respond with a larger number of neurons, causing a song with better syllabic richness without pushing sexual maturation too far, shortening the duration of the critical period.


*The nucleus of the archistriatum is part of the bird's song system and will be looked at more closely in the second part of this article.

*The use of exogenous hormones seems to be a common practice in some parts of the world, even though it remains controversial. So long as shows which are staged later in the season become more widespread in the US, perhaps this controversy can be avoided. The author makes it clear that there is some considerable risk in using this artificial aid (impoverished song, etc.), and a more natural period of song development is to be preferred--trans.


 

   
   
© Vicente Jerez Gomez Coronado
© Translation Sebastian Vallelunga

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