178 TROPIC-BIRDS 
son’s Petrel is doubtless the most common. It breeds in the islands 
of the South Atlantic in February, and after the cares of the breeding 
season are over migrates northward to pass its winter off our coasts. 
At this season its home is the sea, and its occurrence on land is gener- 
ally due to storms. .For this reason, and because of its long migra- 
tion, it is the Petrel most frequently observed in western Atlantic 
waters during the summer. 
Under the name of “Stormy Petrel,’’ or ‘‘Mother Carey’s Chicken,” 
these birds are familiar to most people who have made sea voyages. On 
tireless wing they follow in the track of a ship, coursing ceaselessly 
back and forth, now beneath the stern, now hovering over the foam- 
flecked wake, reminding one of white-rumped Martins in their easy, 
graceful flight. If food be thrown overboard, they are at once attracted 
to it, and soon are left far behind, a little group of black, fluttering 
forms on the surface of the ocean. The meal disposed of, a few rapid 
wing-beats bring them to us, and again they resume their patient beat- 
‘ing to and fro. 
1905. Jos, H. K., Wild Wings, 191 (off Mass.). 
The WuITE-BELLIED PETREL (110. Fregetta grallaria) is a tropical species 
which has been taken once in North America—at St. Marks, Fla. 
The Wuire-Facep Petren (111. Pelagodroma marina) inhabits the 8S. 
Atlantic and southern seas. It is of accidental occurrence off the coast of 
Massachusetts. It may be distinguished from any of our small Petrels by 
its white underparts. 
IV. ORDER STEGANOPODES. TOTIPALMATE SWIMMERS 
9. Famity PHarTHONTIDa. TRopIc-BIRDS. (Fig. 28.) 
The six species comprising this small but distinct family are dis- 
tributed through the tropical and subtropical seas of both hemispheres, 
but none regularly reach the United States. Tropic-birds frequent the 
high seas. They fly with quick, strong beats of the wing, quite unlike 
the more leisurely stroke of Gulls; and from Terns they may be known 
by the long, willowy tail-feathers which add greatly to their appear- 
ance when in the air. They hunt for food by beating back and forth 
over the water and plunging abruptly down upon it. 
Tropic-birds lay their single brownish, purplish egg on the bare 
ground or rock, in a burrow or crevice often some height above the 
water. Incubation is said to be performed by both parents. When on 
the nest, they vigorously resent being disturbed, by screaming, biting 
and scratching. 
; 112. Phaéthon americanus Grant. YELLOW-BILLED TROPIC-BIRD. 
(Fig. 28.) Ads.—White; a mark before and through eye; outer web of pri- 
maries, lesser wing-coverts, and tertials black; flanks streaked with slate; bill 
yellows ae tinged with salmon, shafts of feathers black. W., 10°75; T., 19°00; 
