EXPEDITION TO LAYSAN ISLAND IN 1911. 13 



habits of the gregarious little creatures. For countless generations 

 they have lived in a crowded community, like the inhabitants of our 

 larger cities, and now, although the killing of thousands of birds on 

 the west side of the island has made nesting places available else- 

 where, they still live as did their predecessors, nesting as closely as 

 possible. 



In collecting birds that had young, much care was exercised not to 

 take both parents and thus to leave the nestlings to perish. This 

 made the collecting of some species difficult and slow. Fortunately 

 we were able to preserve and so utilize many birds that were found 

 dead on the rookeries, the mortality from natural causes being large. 



LIST OF BIRDS ON LAYSAN. 



It is not my intention to attempt to duplicate the excellent report 

 on the birds of Laysan Island by Dr. Walter K. Fisher 1 in 1902, to 

 which readers are referred for many details here omitted. We found 

 the same species that he did, with the addition of Bulwer's petrel and 

 the sooty petrel (Oceanodroma tristrami) . The following is a list of 

 the island birds, with notes on their distribution, habits, nests and 

 eggs, etc., as observed by our party: 



LARID.E. 



Sterna fuliginosa Gmelin. Sooty-backed Tern. 



Upon our arrival at Laysan we did not observe many sooty-backed 

 terns. There was a small colony of about 500 birds on the southwest 

 part of the island and another of about the same size on the extreme 

 east. We found great piles of bones near the former that led us to 

 believe that the birds had been much reduced in numbers by the 

 plumage hunters. 



About the 6th of May thousands of them appeared on the east side 

 of the island and about a week later others came to the southwest. 

 Their numbers increased each day. As the southwest rookery grew, 

 it extended toward the north. For some reason known only to them- 

 selves the birds confined their nesting to the area on the west side of 

 the small car track, which is indicated on the accompanying map. 

 We found a few nests between the rails, but none on the east side of 

 the track. The first day of June we measured the rookeries of these 

 birds, and two days later we went over the same ground again. We 

 found that in two days the rookeries on the west side had increased 

 in area 3,600 square yards. 



The final estimate of the number of sooty terns was made June 4 

 333,900 for both rookeries. This species outnumbers any other on 

 the island. We found as many as 7 and in some cases 9 nests to the 



1 Birds of Laysan and the Leeward Islands, Hawaiian Group, in U. S. Fish Commission Bulletin for 

 1903. 



