Correspondence



123



close to the limit of germination power, and that such eggs are practically

useless when incubation is started after four to six weeks.


Now the eggs of Waterfowl and Gallinaceous birds are comparatively

very “ delay-proof ”, as, in nature, incubation often does not begin before

the completion of a rather large clutch.


Thick-shelled or oily-shelled eggs (such as those of Guineafowl or the

Mallards) seem to be more resistant than porous ones, and we may also say

that the smaller the size of the egg, the more rapidly it loses its chances of

proper germination.


This is, perhaps, largely due to over-evaporation; the ratio “ surface-

versus-volume ” being the simplest geometrical explanation of it.


It is hard to believe that the minute and fragile eggs of Grass Parrakeets

would be unusually resistant to staleness and desiccation.


It is then reported that these Parrakeet eggs were placed in an incubator

with the above-mentioned success !


We must infer that, from their first day, the young were actually hand-

reared—and we are already aware of the skill required to hand-rear a baby

Budgerigar or even a larger Parrot.


Using other Parrakeets as foster-parents has, up to now, been generally

disappointing; the Budgerigars, especially, seem hopeless for rearing any

young Grass Parrakeets, and even the best hen Bourke’s is generally useless

for any youngster of the “ green ” Grass Parrakeets.


It would, therefore, have been quite valuable to learn by what method the

prosperous stock of Siberian Blue-wings was actually started.


The extraordinary prolificacy of that stock—up to four nests per annum

with common clutches of eight!—seems to point to exceptionally skilful

management and the favour of a Siberian climate.


In Belgium we are not so happy, and we have to treat our Blue-wings

as semi-hardy birds. En resume, Professor KharklofFs reported achievements

are valueless for avicultural or scientific purposes while we have not more

complete and detailed information of the technique adopted by him.


His claim to have “ fixed eight definite colours ” among his stock of

Neophema chrysostoma in ten years must be substantiated by better references

and descriptions before being seriously considered—especially so because

we have not yet an authentic record of any established “ sport ” or mutation

in the Grass Parrakeet group.


Possibly the explanation of the whole thing will be found in some letter

written in Russian and incorrectly translated by the Tasmanian correspondent

of Mr. Webber. I should not like to hurt Mr. Webber’s feelings by my apparent

scepticism, but, on the other hand, I foresee that, in going over our printed

records, the future aviculturists of half a century or so may get some queer

ideas from such articles about our avicultural methods of 1938.


I would suggest, also, that correspondents should be asked for fuller

information when such bald statements are submitted for publication in

our Magazine.


J. M. Derscheid, F.Z.S.,


Professor of Biology,


Colonial University of Belgium.


When I acknowledged receipt of Mr. Webber’s article I asked him to find

out all he could about Professor KharklofFs wonderful achievement and to

report it as fully as possible for publication in the Avicultural Magazine.

—Editor.



