EXPEDITION TO LAYSAN ISLAND IN 1911. 

 0. tristrami. 



MEASUREMENTS BY MR. RIDGWAY. 



19 



Sex. 



Date. 



Length. 



Wing. 



Tail. 



Fork 

 of tail. 



Oil- 

 men. 



Depth 

 hill front 

 of nostril. 



Tarsus. 



Mid. 

 tcl. 







Skin; 

 about 11 

 inches. 



7.50 



4.45 



1.60 



0.70 



0.25 



1.10 



1.10 









SKINS COLLECTED ON LAYSAN BY OUR PARTY. 







Apr. 28 

 May 22 

 May 29 



10.00 

 9.8 

 9.00 



7.00 4.3 

 6.54 4.1 

 5.8 4.16 



1.50 0.8 

 1.20 .8 

 1.25 .76 



0.22 

 .20 

 .20 



1.02 

 1.04 

 .94 



1.04 

 1.06 

 1.16 



PHAETHONTID^. 

 Phaethon rnbricaudus Boddaert. Red-tailed Tropic Bird. 



During the first three weeks of our stay on the island we saw very 

 few red-tailed tropic birds (PI. VI, fig. 2) . They were wild and very 

 hard to catch. Later, however, we saw plenty of them, and as they 

 were nesting, we experienced no trouble in catching them in our 

 hands. 



This species has by far the most beautiful plumage of any of the 

 birds found here. Its rose-tinted satin body, with bright coral red 

 beak, and its elongated central tail feathers make it a striking bird 

 indeed. 



The poachers have killed many of these birds, but they still seem 

 fairly abundant, numbering about 300. 



SULID.E. 

 Sula cyanops (Sundevall) . Blue-faced Booby. 



A small colony of blue-faced boobies (PI. VII, fig. 1), was nesting 

 on the sandy beach of the east coast. By actual count, 45 birds 

 were there during the first week in May. Large downy young were 

 in the nests, usually one but in some cases two. A few eggs were 

 found, but all were well incubated. 



On the 5th day of June we were somewhat surprised to find about 

 twenty pairs of these birds nesting on the interior slope of the east 

 side of the island in close proximity to the man-o'-war bird rookery. 

 Why they should choose such an environment is hard to understand. 

 Nearly all the nests contained two fresh eggs. 



Not far from this spot we saw a man-o'-war bird pursuing a booby 

 which had just returned from fishing, with a crop full of fish. At 

 first it seemed as though the booby would outfly its pursuer, but its 

 load was too heavy. The man-o'-war bird overtook the booby, 

 seized it by the tail, raised itself in the air, and turned the booby 

 completely over. Being thus rudely overturned the booby lost 



