The Northern Black Swift 
while the birds themselves differ in length by less than two per cent. 
What the determining cause of this extraordinary difference in size may 
be, we cannot yet see; but it is fair to conclude that the infant niger must 
be much further developed at birth than are his baby cousins. As the 
exclusive recipient, also, of parental favors, it is safe to predict that 
his growth is rapid, and his hazardous sojourn in his surge-crooned cradle 
a brief one. These are children of the upper air, and their scorn of the 
ground may have become embodied thus in an effective device for being 
quickly quit of it. 
Since writing the above I am informed by Mr. DeWitt Miller, then 
in the service of the American Museum, that he has found nests of a 
related species, the Brown Swift (Cypseloides brunneitorques brunnei- 
torques ), in the mountains of Peru; and that this bird lays only one large 
egg. The South American Brown Swift, however, makes a shapely 
nest of moss, which it attaches to the side of a cliff. The Black Swift 
seems to be unique in its deposition of its egg upon the bare, moist earth. 
There are, however, distinct indications that this careless habit is a recent 
devolution. Yrooman has found several eggs whose support was a well- 
coiled cushion of grasses, and one of these at least whose formal propor¬ 
tions deserve the title of nest. 
The sea-faring instinct displayed by these birds is hard to understand, 
but that it is a deep-seated one the following account will show. In 
the summer of 1920, when Mr. Vrooman was out after his annual toll, 
he came upon a youngster in the pin-feather stage, unseasonably early, 
albeit with well developed flight-feathers. Juvenal specimens are rare 
and very desirable, so the collector, who was dodging the waves on the 
beach below, essayed to dislodge the chick with a pole, intending to 
snatch him and run before a wave caught him. The nestling tumbled, 
but when within two feet of the ground recovered itself, rose to a height 
of six feet, and set out bravely to sea. In helpless astonishment the 
veteran collector watched this waif as it fluttered and wobbled or circled, 
but ever seaward, until it passed from sight. Never a thought, ap¬ 
parently, for the parent cliff or of terra firma, but only for that ancient 
beckoning siren whose bosom could have meant nothing but a grave. 
It was too uncanny! 
For myself I have followed this will-o-the-wisp for thirty years— 
not on Vrooman’s preserves, of course, that would be ungentlemanly— 
but never a sight have I had of the alabaster oval beyond the glimpse 
afforded me by Yrooman’s skill that day in June. But someone, some¬ 
where, will make a strike. The birds undoubtedly do nest in the moun¬ 
tains; and they must occur elsewhere along the sea coast. As a sporting- 
proposition I place my accumulated “dope” at the service of the public— 
