as 
Py eo te eT 
174 
The Scream of the Young Burrowing Owl sounds like 
the Warning of the Rattlesnake = 
WHILE working upon the tertiary beds of the plains east 
of the Rocky Mountains recently, I had numerous op- 
portunities of making observations on the habits of those 
peculiar creatures the Burrowing Owls (Spfeotyto Aypogwa). 
Among others made at the time is one relating to the extra- 
ordinary similarity between the sound of the cry of the young 
owl when disturbed, and that of the warning of the Rattlesnake 
(Crotalus confiuentus), which I do not find to have been noticed 
by ornithologists. My attention was first called to the peculiar 
likeness by my friend, Dr. V. T. McGillicuddy, who had in his 
possession a couple of owlets nearly as large as the adults. The 
capture of a number of both snakes and birds enabled me by 
experiment to determine to what extent one might be deceived 
by the resemblance. At the distance of a few feet the shrill 
tremulous scream would deceive persons quite familiar with the 
sound of the rattling of the Crotalus. When not noticing or 
thinking of the birds, their cry produced on us the same effect as 
the sudden springing of the rattle by an angry snake. The ex- 
periments left no doubt that the cries produced a similar effect 
on other animals which unwittingly disturbed young owls. And 
in this way they led to a consideration of the possible benefit of 
this close resemblance, or, as it might be called by some, 
mimicry. As youknow, the birds are fond of the deserted holes 
of different burrowing animals, especially so of those of various 
Spermophiles or Prairie Squirrels. They are common in and 
about colonies of the so-called ‘‘ Prairie Dogs” (Cynomys 
ludowicianus), where they take possession of vacant burrows, 
and sometimes even of thosein use, sooner orlater dispossessing the 
rightful owners, as the dogs seem disinclined to bring eyesand noses 
into contact with the sharp beaks.and claws in the passages how- 
ever familiar they may be with the birds around the mouths of the 
dwellings. In the same localities the snakes are numerous, and the 
squirrels form a considerable portion of their prey. Naturally 
enough the rodents—as also the weasels, foxes, and coyotes 
{Canis latrans)—dread the fangs and venom, and recognise and 
profit by the warning. May it not be that the peculiar protest 
or scream of the young owl, by its resemblance to the danger- 
signal, insures safety by preventing the approach of the mam- 
mals, and, possibly, of the dull-eared snakes themselves? The 
scream of the old bird is rather more hoarse and somewhat less 
like the shrilling of the serpent. On ordinary occasions, the 
note of this owl is a cackling or chuckling chatter or laugh, 
varied with what seem very much like imitations of the barking 
and squealing of the squirrels. When caught, it gives utterance 
to the hoarse, long-drawn, rattling scream. 
greedily of fresh meat, stopping to utter their strange cry of alarm 
at every attempt to approach them. In behaviour the adults were || 
similar, but much less tractable. One, which had his wing 
broken, was allowed the freedom of the camp, and usually he 
stowed himself under the waggon. A halt in a ‘‘dog-town” 
one day brought him near one of the holes, which after a time 
he discovered. At once his soldierly walk quickened; it 
became a quick step as he neared the opening, Chuckling to 
himself, down into the darkness he plunged, and that was the 
last we saw of him. S. GARMAN 
Cambridge, Mass., U.S.A., December 3 
Fertilisation of the Common Speedwell 
Ir Mr. Ransom will refer again to my letter, he will see that 
it was written in order to draw attention to the adapéation of 
the flower for cross-fertilisation, and not especially to the fact 
that Diptera in settling upon it, draw down the stamens. ‘This 
latter, if we consider the close attention paid of late years to the 
commoner European wild flowers, has in all probability been 
frequently observed before. As I have not seen Schenck’s hand- 
book, I would be gladif Mr. Ransom will quote the passage 
to which he refers. On looking at my note-book I find that not 
only V. officinalis, but also V. Chamadrys and V. Beccabunga 
are shown as fertilised in the same manner. May I suggest 
that the separation of the stamens, and the difference of inclina- 
tion between stamens and pistil, have been brought about in 
order to prevent self-fertilisation? The looseness of the corolla 
would then, in such a flower as . Chamadrys, bring the anthers to 
a level with the stigma when an insect alighted upon it, and would 
thus promote cross-fertilisation, From want of more extended 
observations, however, I could not say what would happen in 
the case of a proterogynous species, or of sucha flower as V. 
The owlets ate | 
a en 
NATURE 
[Dec. 21, 1882. 
spicata, In reply to Mr. Ransom, I may add that I have no- | 
where stated V. officinalis to possess larger flowers than V. 
hedereefolia, and that Mr, Darwin (‘‘ Cross and Self-fertilisation,” 
p. 369), in a brief reference to the genus, simply states that 
agrestis is self-fertilising, and mentions species of Syrphidze as 
visiting the flowers of V. hederefolia and V. officinalis. 
» A. MACKENZIE STAPLEY } 
The Owens College, Manchester, December 15 
Complementary Colours at the Falls of Niagara 
Ir Mr. Cross, whose letter on the above subject appears in 
Nature (vol. xxvii. p. 150), will make what is for him a very 
short excursion from Boston to Niagara, he will see a very 
perfect and permanent illustration of contrast-colours. In the 
American fall, the pure, green, even sheet of water is “ trimmed,” 
as it were, at regular intervals by broad bands of foam, which 
although, of course, really white, appear of a delicate rose-pink 
hue, I noticed, and ‘‘ made a note of this” ten years ago, and 
again this year. The effect heightens the beauty of the beautiful 
fall, and I am surprised that no poet has made capital out of it. 
I should like to call attention to the rapidity with which the 
Canadian fall is deepening its horse-shoe. An immense mass 
broke off near the middle of the curve in October, 1874 (many 
windows in the adjacent museum were broken by the concus- 
sion), and altogether the fall has receded twenty-four feet in ten 
years. H. G. MADAN 
Eton College, December 15 
M. DUMAS 
HE following is a translation of the addresses deli- 
vered in the Paris Academy of Sciences on the 4th 
inst., on occasion of a commemorative medal being pre- 
sented to M. Dumas :— 
‘The President, M. Jamin, said : Gentlemen and dear 
Fellow-Members : The Academy considers it a duty to 
celebrate the golden wedding of those fellow-members 
who have honoured it during half a century, a duty which 
is always dear to us, but to-day is dearer than ever ; for 
M. Dumas now completes his fiftieth Academic year. You 
have had prepared, by an able artist, a medal which 
happily recalls his features, and must perpetuate them ; 
it bears on the back this inscription : 
A M. DuMas 
SES CONFRERES, SES ELEVES, SES AMIS, 
SES ADMIRATEURS. 
I have nothing to add, except that it is not all his 
admirers, all his friends, all his scholars, but only those 
who sit here; the Academy has not been willing to 
share with any stranger the duty of a homage which it 
has exclusively reserved to itself. I have the honour to 
offer in your name, with respect, to our illustrious and 
venerated fellow-member, this token of our affection and 
| of our gratitude. 
My dear Teacher : If you will carry back your thoughts 
to the commencement of your career, you may well be 
content with your lot and with yourself. When twenty- 
two years of age, you were at Geneva; you began with 
Prevost, by discoveries that are still celebrated in physio- 
logy, on the urea, on the blood, and on generation. From 
that moment your name was known, and you acquired 
confidence in yourself. Then you perceived two things : 
the first, that physiology must be built upon chemistry, 
that chemistry was not made, and that it was necessary 
to make it; the second, that Geneva was not a large 
enough theatre for your projects. And so you came to 
Paris, having no other wealth than yourself, than your 
courage, than a programme resolutely determined, than 
the will to fulfil it, than confidence, still unconscious of 
the future that was promised you. Now the time has 
advanced, your dreams have been realised, your hopes 
exceeded, and you have reached the highest degree of 
glory a savant can conceive. Like Franklin, you may 
: 
. 
