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Jan., 1922 NOTES ON THE DIPPER IN YELLOWSTONE NATIONAL PARK 19 
then the Dipper coasts along ten feet with the acquired momentum before tak- 
ing up his wing strokes again. Except for the quarter mile flight already re- 
corded, I have seldom seen a Dipper over land; indeed, this bird is noted for 
the fidelity with which he follows the waterways. A bird will come flying 
down one stream, turn an acute angle at the mouth of a second stream, and 
then go buzzing merrily up it after flying three times as far rather than cross 
the neck of land between the two streams. In following an irrigation ditch, 
one will turn at a right-angle promptly with the ditch. A pair that fly up 
along the power pen-stock to our reservoir come the nearest to flying regularly 
over land of any that I know of. Sometimes in chase and pursuit, the rule is 
forgotten until the excited birds find themselves over the unfamiliar dry sur- 
face. 
Usually a Dipper flies close to the water, but I have seen one flying along 
thirty feet above the surface. When ready to alight he chooses either the shore 
or the water surface, although I believe he prefers to alight on a running 
stream and swim ashore! In the ease of still water, he certainly prefers alighi- 
ing on the surface. It appears easy for him to take flight again from the water. 
The song is a loud, clear, bell-like strain, the very essence of happiness 
and joy, ringing out high above the rush and roar of all but the heaviest of 
rapids. Still sweeter by far is it when heard in the depth of winter. Al- 
though rapids may sometimes dim the music, often there is a ringing echo from 
the cliffs to reinforce it. Beginning about November first, the song season 
reaches its height in February and March. I have heard the Dipper sing on 
clear, sunshiny days when the temperature was down below zero; I thought it 
anything but spring-like, yet these musicians sang cheerily in spite of ther- 
mometer readings. Usually squatting on a stone out in the stream, where er- 
rant drops of water often dash over them, with head and neck slightly out- 
stretched, they are very still and quiet while singing, except for occasionally 
turning their heads, and ‘‘winking’’. Their stone platforms are from three 
to ten inches above the water, and the motionless singers are hard to see. They 
do not dip while actually singing, but often do during the pauses in the song. 
Sometimes they sing while in flight, and occasionally I have heard a song from 
a bird running along shore. At times I have seen a Dipper diving one instant 
and the next he was in full song, only to resume diving and feeding shortly 
after. While Dippers prefer to sing on warm, spring days they frequently 
sing also on zero days, and often the clear notes ring out during the severest 
of snow storms. Once J found one singing a merry lay in a heavy snow driven 
by a high wind that I did not at all care to face myself! 
An angry, hissing note used when chasing off intruders is so distinctive 
as to point out the bird at once; such a striking sound attracts attention the 
instant it is heard. 
Dippers run along the shore ice, swim in, as well as on, the water, and 
dive in “‘all over’’ as they please even when the thermometer is far below 
zero. With feathers oiled against wetting, a bird under water is easily seen 
because of the silver air bubbles adhering to the plumage. They sing, play, 
and dive during cold, north winds that drive even the hardy Nutcrackers to 
cover. Dippers are unaffected by cold, remaining along the upper Yellow- 
stone during November and even later, the very quintessence of hardihood! 
Properly speaking, they do not migrate, but the freezing of some of the 
