136 BULLETIN 121, UNITED STATES NATIONAL MUSEUM. 



Doctor Grinnell (1897) who was forced to spend a night on St. 

 Lazaria Island, had an unusually good opportunity to study the 

 midnight flight of the forked-tailed petrel on its breeding grounds, 

 which he graphically describes as follows: 



After the sun set and the long summer twilight began to make the woods a 

 little gloomy, the petrels became more active. Their curious calls came from 

 every direction in the ground, though as yet not a bird was to be seen. Pres- 

 ently a little stir in the grass called attention to a petrel which clumsily 

 scrambled from his hole, and after the usual fumbling put himself in flight 

 and betook himself speedily out to sea. Soon others appeared and others and 

 others. The crows, their enemies, had by this time gone to roost, and as the 

 gloom grew deeper the petrels became more numerous. Those which had been 

 out to sea all day began to arrive among the trees, and were even more awk- 

 ward than those leaving. They flew against branches and hughes and into my 

 face, but all ultimately seemed to know where their respective homes were. 

 The chorus of their cries was curious and depressing to one's spirits, and the 

 chilly air was constantly being fanned into my face by their noiseless wings. 

 The light-colored ghostly forms of the forktails were much more readily dis- 

 cernible than the dark Leach's. 



The ground was alive with struggling petrels, and I picked up as many as I 

 chose. As the twilight of evening slowly merged into dawn the height of 

 their activity was reached. I walked from end to end of the wooded part of 

 the island, and everywhere the petrels were equally numerous. 



As I began to feel cold and likewise hungry, the novelty of these strange 

 experiences naturally wore off. After considerable searching for dry fuel I 

 started a smoldering little blaze, which lighted up the dusky surroundings, 

 together with the flitting forms of the birds, thus disclosing a very impres- 

 sive scene. But presently several of the petrels were attracted by the light 

 and flew pell-mell into the fire, extinguishing the feeble flames in short order. 

 After several similarly frustrated attempts, though partly on account of the 

 damp wood, I gave it up. 



As soon as the dawn became perceptibly brighter the petrels became quieter 

 and fewer. Part went out to sea ; others returned to their nests. By sunrise, 

 at 2.30 a. m., not a petrel was to be seen nor a note heard where two hours 

 before had been such a tumult of nocturnal forms and voices. The crows set 

 up their saucy cawing and the western winter wrens and sooty song spar- 

 rows announced their presence with their clear musical trill. 



The vocal performances of this species have been referred to 

 above. They consist of a variety of soft twittering notes, given in 

 flight while flitting about their breeding grounds, or faint squeaking 

 notes when disturbed in their burrows or when handled. But, being 

 nocturnal in its activity and being so intimately associated with 

 other species, it is not easy to distinguish its note with certainty. 



In its association with other species it is gentle and harmless itself, 

 but it has many enemies. In the Aleutian Islands it falls an easy 

 prey to prowling foxes, which dig out its nesting burrows, killing 

 and eating both old and young; it has been practically exterminated 

 on the islands where foxes are abundant. The minlt and other pred- 

 atory animals destroy large numbers. On St. Lazaria Island, Doc- 

 tor Grinnell found evidence that crows were also destructive in dig- 



