282 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



any tern colonies that I have ever heard of elsewhere. Mr. E. W. 

 Gifford (1913) says: 



Messrs. Beck and Hunter reported sooty terns nesting by thousands on 

 several low, flat islets in the brackish lagoon at Clipperton Island. On one 

 islet, about 800 square feet in area and 10 inches in elevation above the water 

 of the lagoon, there were over a thousand eggs. They were laid on the bare 

 coral, with no semblance of a nest, and were so closely placed that it was 

 necessary to step with extreme care to avoid crushing them. The owners were 

 very fearless and allowed themselves to be handled freely. They were also 

 very noisy and kept up a great din. On the 9th 400 eggs were collected by 

 the two residents of the island from a space 20 by 20 feet, and by 11 a. m. on the 

 10th over 100 fresh ones had been laid in the same area. 



The colony on Laysan Island is probably the largest, and it cer- 

 tainly is a wonder among wonders. Prof. Homer R. Dill (1912), re- 

 porting on the condition of this colony, states : 



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. 



Dr. "Walter K. Fisher (1906), writing of the same colony, says: 



The sooty terns nest in among the tall grass, and the single egg is laid directly 

 on the sand, with sometimes scarcely a hollow to suggest a nest. The eggs 

 are placed very close together in many localities — so close that it is sometimes 

 difficult to progress and not walk on them. The birds are very loath at times 

 to leave their nest, and scold soundly before finally slipping ofE. When at last 

 driven, they limp away, dragging their wings in a painful manner, just as our 

 own birds do. Thus, here, on a little island, is this firmly implanted instinct 

 strongly in evidence, and practiced where it can be of no possible advantage to 

 the bird. Sometimes a dozen or more will struggle on ahead of the pedestrian, 

 trampling over each other and crying incessantly, kicking eggs to the right 

 and left in a mad endeavor to escape, while overhead their fellows keep up an 

 incessant screaming. There is always a great cloud of these birds flying back 

 and forth over the colony, even when no disturbing element is present. 

 They seem to need the nervous excitement. Just at sunrise they are spon- 

 taneously most noisy, for they apparently are returning from the sea, where 

 I have heard them at various times during the night. 



Eggs. — The same writer gives a very good description of the eggs 

 of the sooty tern, and I can not do better than quote his words, as 

 follows : 



The eggs of the sooty tern vary much in markings, but can usually be told 

 from those of Sterna lunata by greater size and usually coarser spotting. The 

 ground color is white or occasionally a cream buff. One type of marking con- 

 sists of deep burnt sienna and grayish vinaceous spots, with occasional nearly 

 black scrawls scattered rather evenly over the whole surface. The spots are 

 1, 2, and 8, mm. in diameter, with occasional larger and smaller ones. An- 

 other less prevalent variation consists of heavy, very deep burnt sienna blotches 

 (5 mm. to 15 mm. in extent), congregated in a zone near the blimt end, and 

 lesser pale grayish vinaceous and deep burnt sienna spots sparsely scattered 



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