On the Difficulty of Sexing Biche?io's Finch. 219


ON THE DIFFICULTY OF SEXING BICHENO’S


FINCH.


By Arthur G. Butler, Ph.D.


Most dealers will tell you that Siictoptera bichenovii can be

readily sexed by the width of the black bands encircling the

throat and breast; but the late Mr. Joseph Abrahams relied more

upon the superior size and darker crown of the cock bird ;

nevertheless that even he, with his vast experience, was some¬

times wrong in his determinations, is evident from the following

facts.


In 1899 Mr. Abrahams wrote to me that he wished me to

try for the Bicheno x Zebra-finch hybrid; therefore about

August of that year he sent me a bird which purported to be a

cock Bicheno’s Finch. I at once paired it up with a hen Zebra-

Finch, putting the pair into one of my flight-cages and providing

them with a nesting receptacle and building material; the two

birds simply ignored one another, one roosting in the nest-box

at night and the other outside.


Seeing that the supposed cock had very narrow bands

across throat and breast, I wrote and told Mr. Abrahams that I

thought he must have inadvertently sent me a hen in mistake

for a cock. He replied that he had been very busy at the time,

so that it was just possible he might have done so ; he was now,

however, sending me another bird which he was quite confident

was a genuine male: with his usual generosity he desired me to

keep both, and see what I could do with them.


Strangely enough the hen Zebra-finch with the first bird

died egg-bound; and that with the second bird was twice egg-

bound previous to April 1900; although no nests had been built

in either cage. On April 15th the first Bicheno’s Finch was

taken ill, and died that night.


In the case of the second bird—the “genuine male,”

although I changed its hen several times, there was no result up

to February 1903. Thinking that, in this case as in the other,

the sexing might have been wrong, I now substituted a cock

Zebra-finch for the hen. The two birds became quite friendly,

went to roost together, but no eggs were laid.



