DECREASE OF GAME 17 



ground-squirrel eradication does not cause the death of California 

 Valley Quail under natural feeding conditions. 



Game birds are as a rule remarkably free from disease in Cali- 

 fornia. Only one serious point of outbreak is known to us, and water- 

 fowl alone were here affected. In 1908, an epidemic broke out among 

 the water birds (especially ducks) in and around Tulare Lake, Kings 

 County, and Buena Vista Lake, Kern County (see Clarke, 1913, pp. 

 214—226), and this has recurred during the summer and fall months 

 of each year since that time. The disease first appears during the 

 hot summer weather, about August, and has run its course at the 

 advent of the cooler weather of October. It then rather suddenly 

 'abates, and no more sick birds are to be found until the following 

 summer. It has generally, though not always, been confined to areas 

 of stagnant water. 



Most of the ducks that die are fat and have the appearance of 

 being in normal condition. The first symptoms of the disease are loss 

 of the power of flight ; following this, the ability to walk is lost. 

 Finally in the later stages, the sick birds sit with their breasts on the 

 ground or mud, and after a few days, during which time a diarrhoea 

 develops, they die, apparently of paralysis. 



During an investigation in 1913 careful counts and estimates were 

 made of the numbers of dead ducks on Buena Vista and Tulare lakes. 

 A conservative estimate for the former lake was 15,000, and 25,000 

 for the latter. Thus a total loss of over 40,000 ducks was sustained 

 in 1913, in the two counties of Kings and Kern, besides many hundreds 

 of other water birds. 



Experiments carried out there seemed to prove that the water in 

 Tulare Lake, which is heavily charged with mineral matter, is respon- 

 sible for the death of the birds. However, during other years many 

 birds have been found dead in this and some other lakes when the 

 water was comparatively fresh. The pface where infection occurred 

 during those years is not definitely known, but is currently supposed 

 to have been near where the birds were found dead. 



Investigations by the United States Biological Survey (Wetmore, 

 1915, jjp. 6-7) of a similar disease occurring around Great Salt Lake, 

 Utah, also indicate an alkaline poison, the exact nature of which is 

 yet to be determined. As was the case in California, a large percentage 

 of affected ducks recovered when placed on fresh water. The increased 

 leaching of the adjacent lands by irrigation may be responsible for 

 all these outbreaks. The only remedy yet suggested is to capture the 

 sick birds and place them on fresh water. 



We know of no other instances of game birds dying as a result of 

 disease except quail which in captivity often fall victims to a "quail 

 disease." This disease is known technicallv as coccidiosis. No cure 



