4 BULLETIN 217, TJ. S. DEPARTMENT OP AGRICULTURE. 



Salt Lake City, who were deeply interested in the work. Valuable 

 information was obtained also from V. T. Davis, in charge of the 

 grounds of the Bear River Club. At the mouth of the Weber River, 

 W. O. Belnap gave all possible assistance, as did other members of 

 the North Shore Gun Club. At the mouth of the Jordan River work 

 was done at the New State Gun Club. Permits for shooting such 

 birds as were necessary for purposes of investigation were granted 

 by the State fish and game commissioner, Fred W. Chambers. In 

 California the State fish and game commission furnished an assistant, 

 Tipton Matthews, deputy warden of Kern County, whose aid ren- 

 dered the work around Tulare Lake effective. 



NATURE OF THE TROUBLE. 



During the season's work in Utah 27 species of birds of 11 families 

 were found to be affected. Among these were 9 species of ducks, 10 

 of shorebirds, and 8 miscellaneous forms ranging from grebes and 

 snowy herons (see PI. Ill, fig. 1) to the pipit. Among ducks the pin- 

 tail and green-winged teal seemed to be most susceptible, while the 

 mallard, spoonbill, and cinnamon teal followed them closely. Avocets 

 and stilts suffered more heavily than any other shorebirds. 



The birds affected first lose the power of flight and are unable to 

 rise in the air, though in some cases they can flutter across the water, 

 and in others can fly for a few rods before dropping back. The legs 

 next become affected and the power of diving is lost. As the birds 

 grow weaker, they crawl out on the mud bars, if able to do so, or hide 

 in growths of grass or rushes. In a later stage of the affection they 

 are unable to rise. Finally the neck relaxes and the head lies pros- 

 trate (see PL II, figs. 1 and 2) . If in the water, death comes by drown- 

 ing, but on land, birds may live for two days or more in this condition. 



A large series of postmortem examinations revealed no patho- 

 logical lesions other than that the intestine was reddened and firm 

 and hard to the touch. When the gut was slit, washed, and examined 

 under a low magnification, the capillaries in the intestinal villi were 

 found to be distended, showing intense irritation. The reddening 

 of the canal appeared sometimes in spots, most severe at the bends 

 of the intestine, but at others it extended continuously from the 

 duodenal loop to the caeca. Clots of extravasated blood, partially 

 digested, were found in most cases, and not uncommonly the caeca 

 were distended with this matter. A severe dysentery occasioned by 

 the irritation of the intestine was the obvious external symptom. 

 The feces were greenish and stained the feathers about the anus and 

 sometimes well up on the abdomen. Large quantities of renal matter 

 were present, white and almost solid, and with an offensive odor. As 

 the food residue in the intestine worked off, this renal matter con- 

 stituted an increasing proportion of the feces, frequently solidifying 



