Nov.,1915 REPORT UPON DISEASE AMONG DUCKS 221 than on the south and east sides. Further, it was out of the question to count all the birds on any of the sections between the levees, as part of this territory was in heavy mud or under water. But taking into account the ducks on these areas and those on the levees, the approximated average for all the territory affected was about one to the acre at the very least. Then figuring 25,ooo acres as the total area of this affected territory, we have a total result of 25,ooo dead ducks, besides many other birds. As stated above, ducks on the lake usually prefer to locate for the day on the old levees where these are very nearly submerged. Where great numbers of birds visited these levees, the latter soon became very filthy. Cir- cumstances favored such conditions. The ground was a soft, black mud, full of , ?ale tinchoJmile Fig. 72. DIAGRAM SHOWING NATURE O1? COUNTRY WHERE EXPERIMENTS WERE CARRIED OuT? AND OBSERVATIONS MADE, ON DUCK DISEASE AT LAKE TULARE, SEPTEMBER 19 TO OCTOBER 7, 1913, BY THE STATE FISH AND GAME COMMISSION decaying organic matter, consequently when visited by thousands of birds, sick and well, all paddling together, these levees became very foul. Sick birds, too weak to travel, were often found stuck in this mud, or even half buried in it.
The first symptom of the disease, so far as could be learned, was the loss of
the power of flight. Following this, the birds became unable to walk. But even after losing this function, they were able to swim and dive for several days, some- times almost up to the point of death. Paddling in the water never seemed dif- ticult, but attempts to dive often failed to take the birds beneath the surface of the water. These functions, of course, were dependent on the condition of the birds. On becoming very weak many.of the sick birds took to the levees where they might
