36 
NATURE NOTES 
full and interesting description of it, with the usual engraving. He calls it “ The 
Bohemian Waxwing,” but says that it is as common in the North of England 
as in Bohemia; that it is “one of the most beautiful of the birds that visit this 
country, but is only a winter visitor, and that, too, at mo.st uncertain intervals. 
It would be interesting to know whether other instances have been observed this 
winter so far south as this. If so, I trust they have not been, and will not be, 
killed. 
Buxled, Sussex, December 8, 1903. A. L. H. 
80. The Speed of Birds and Motor-Cars. -We have become 
accustomed to seeing every week widely differing estimates of the speeds of motor- 
cars : what the prosecuting policeman calls twenty-five miles an hour the defen- 
dant owner and his driver put at ten or eleven. But these discrepancies are 
slight compared with the figures put before us by different writers as to the flight 
of birds, e.g., of swallows. Gilbert White writes (Letter 57), “ they exert a 
rapidity almost too quick for the eye to follow”; and of swifts (Letter 62) that 
they “ dash through the air almost with the inconceivable swiftness of a meteor.” 
Mr. Hudson also says “ It would be within the mark to say that the swift, in a 
sense, ‘ puts a girdle round the earth ’ two or three times a month.” Taking the 
mean of two girdles and a half, this makes 60,000 miles say in thirty days; or 
2,000 a day, or (at sixteen hours a day) 125 miles an hour. And even this is 
barely a quarter of the speed ascribed by your indefatigable correspondent, Mr. 
Daubeny, in his interesting paper on diving birds, to the Virginian plover. Con- 
trast with these figures the subjoined paragraph, taken originally, I believe, from 
the Field, which has never accepted Herr Gatke’s estimates. “ Some timing 
experiments, conducted by Mr. Alfred Walker, seem to indicate that appearances 
are exceedingly deceptive so far as the speed of a bird’s flight is concerned. 
Swallows, Mr. Walker tells us, in their lightning-like evolutions, only fly from 
fifteen to twenty-five miles an hour, which is much slower than the ordinary flight 
of a rook. Starlings, when going to their roosting-place, attain a speed of forty- 
five miles an hour, which is equal to that of the best homing pigeons ; but they 
fly during the day at a slower rate. A wild duck was found to attain a speed of 
thirty-six miles an hour in a short flight. Homing pigeons have been recorded to 
fly at a rate of thirty-three miles an hour on a twelve-hour journey, thirty-six 
miles an hour on a four-hour journey, forty miles an hour on a one-hour journey, 
forty-eight on a ten minutes’ journey, and fifty-two on a one-minute journey.” 
I admit, of course, that there is no reference here to the Virginian plover ; but it 
would be interesting to have the data on which the .several writers have based 
their conclusions. It is suggested that birds can fly faster at great heights, 
through a less dense medium ; well, as counsel for the defence, I should like to ask 
Herr Giitke, as the policeman, how in that case he was able to satisfy himself that 
his measured mile was traversed in less than six seconds. 1 should also like to 
suggest an experiment of this kind : let a toy steamboat be adjusted to steam 
the length of a lo-foot tank of water in five seconds. Then substitute for the 
water oil of half its specific gravity, and start the steamer again. If thought 
proper, remove ballast .so as to secure equal immersion in both trials, although I 
do not know by what means a bird can reduce its own specific gravity in the air. 
The oil will, I suppo.se, offer less resistance to the bows of the boat, but also give 
less grip to the paddles. What will be the net result to the boat in the oil, 
and to the bird in the thinner air? 
Olham Parsonage, Maids/ouc. h'. M. Mii.larI). 
81. Avocet. — A specimen of this Egyptian wader, which is sometimes seen 
in this country between March and September, but very seldom at this time of 
year, is recorded from Yarmouth. Its .stretch of wing was 2 ft. 3J in., but its 
weight only iij oz. It was of course shot, the perpetrator of its death being a 
Mr. E. A. 11. I’ownall. 
82. Humming in the Air. — With reference to note on page 17, I ni.ay 
say that when walking over Selsley Common, near Stroud, Glos. , a “humming 
in the air” may often be heard on still, hot days. Eor some time I was in doubt 
as to the cause of it, as apparently no bees were to be seen ; but one day’ when 
walking on the common with two companions, after keeping a sharp look out, we 
