BIOLOGICAL SURVEY. 237 



Further experiments and observations seem to prove beyond a rea- 

 sonable doubt that the trouble arises from the presence in the water 

 of an alkali that is absorbed through the alimentary canal in fatal 

 quantities. 



It was ascertained that a similar trouble exists at Tulare Lake, 

 CaL, and results there also in the death of many waterfowl. An 

 assistant engaged in the work visited this locality in November in 

 order to study local conditions. A report on the progress made was 

 published in May. 



DESTRUCTION OF OYSTERS BY CERTAIN WILD DUCKS. 



Examination of stomachs of wild ducks secured from near Olym- 

 pia, Wash., definitely supported a charge that certain scaups and 

 scoters were doing considerable damage locally to oyster beds. Dur- 

 ing the ducking season of 1914^15 investigations were carried on by 

 an assistant of the Survey on the headwaters of Puget Sound and 

 the whole of Willapa Harbor, and noteworthy damage was found to 

 be confined to a single bay — Oyster Bay — 18 miles northwest of 

 Olympia, Wash. 



Two species of ducks — the greater scaup, or bluebill, and the 

 white- winged scoter, or coot — were found to be doing all the damage. 

 The average numbers of these birds present on Oyster Bay during 

 the season were 2,000 and 300, respectively. An estimate (subject to 

 revision) was made that these ducks were destroying about 8,000 

 oysters daily, the money value of which would be $20. This would 

 amount to about $3,600 for the duck season. Effective measures for 

 relief are in force. 



FOOD OF WILD DUCKS. 



The work of the bureau in acquiring and disseminating informa- 

 tion regarding the propagation of plants best suited for wild-fowl 

 food has been greatly appreciated by game protective associations 

 and individuals interested in the preservation and propagation of 

 native wild fowl. In response to requests for information of this 

 nature, a third publication in the series on important wilcl-cluck foods 

 was issued in May. This bulletin treats of 11 groups of plants, in- 

 cluding 2 fresh-water plants of wide distribution in the United 

 States ; 2 of more southerly range ; 2 trees of southern swamps whose 

 abundant seeds are eagerly eaten by ducks; 1 strictly salt-water duck 

 food, the first thus far recommended by the bureau ; 1 brackish-water 

 plant; and 3 others of such luxuriant growth as to be especially 

 adapted for use on duck farms. 



THE EUROPEAN STARLING. 



The European starling, an introduced species, continues to increase 

 in numbers and to occupy new territory. Reports of the bird's 

 activities are somewhat conflicting. That it is to some extent bene- 

 ficial is proven by its destruction of insects, especially in summer. 

 In some localities, however, it is charged with the destruction of 

 small fruit, and unquestionably its presence in numbers is inimical 



