196 FOOD HABITS AND REQUIREMENTS 



are those used by orchardists and foresters involving sprays, in which lead arsenate and nico- 

 tine sulfate are commonly the basic ingredients. The birds then run the double risk of eat- 

 ing either the poisoned insects or the plant parts covered with spray. 



Whitehead™* found that neither poisoned grasshoppers nor the bran-poisoned bait which 

 killed them are apt to be consumed in sufficient quantities to cause many deaths among avian 

 populations, either domestic or wild. Nor is there much danger of humans being poisoned 

 from eating chickens that have eaten poisoned grasshoppers. Piper*", however, reported that 

 a large number of magpies and blackbirds fell victims to poisoned grain scattered about in 

 efforts to combat a Nevada mouse plague, where str\chnine was the poison used. 



To gain some insight into the effect on grouse of some of these poisons, three birds at the 

 Center were offered their regular daily ration to which had been added powdered lead arsen- 

 ate equivalent to 0.6 gallons of spray solution at the ratio of one pound arsenate to 40 gallons 

 of water. Within three days the birds showed the effects of poisoning — loss of appetite and 

 droopy appearance. Autopsy revealed bile-stained gizzard lining similar to that found in 

 ducks suffering from lead poisoning. This might be taken to indicate that the lead in the 

 compound is the lethal factor. These birds consumed the equivalent of better than a half- 

 pint of solution each before succumbing on the sixth day of the experiment. It would take 

 many more sprayed fruits, buds and leaves than grouse might be expected to consume in the 

 wild to equal the amount of poison administered. 



To determine the repellent effects of spray solutions of lead arsenate, two food travs. one 

 containing untreated rations and the other sprayed with the solution were placed in a pen 

 with four grouse. No tray preference was exhibited. The proximity of a bird to one tray 

 or the other seemed to be the only factor in determining from which it would eat. 



Since nicotine sulfate is also commonly used as a commercial spray, the al)(>\e experiment 

 was repeated using a standard solution of two level teaspoonfuls to one gallon of water. 

 None of these birds showed ill effects. 



Grouse were also found to be surprisingly resistant to powdered strychnine. The minimum 

 lethal dose of most humans is 0.5 of a milligram per kilogram* of body weight. Three birds 

 were fed respectively 92. 108 and 126 milligrams per kilogram of body weight. All survived. 

 The amount of strychnine consumed was respectively equal to 184. 216 and 2.52 times the 

 lethal dose for humans. 



Although the birds were found to be tolerant of powdered strychnine. 80 milligrams of the 

 same chemical in solution caused death within a few minutes. .Strychnine does not mix 

 readily with water so that solutions such as here tested are seldom used. 



DIET 



In considering the food of grouse it is common to ascribe too much importance to the 

 species most commonly eaten. It is generally believed that the birds exercise a choice of 

 food items based on need. Were this the storv. food habits research would be tremcndouslv 

 simplified, for one would have onl\ to determine the relative consumption of various foods 

 by seasons, regions and \cars for adults and chicks. Knuwing the volume of each food eaten, 

 one could then easilv cinnpilc a list of plant and aninial species to be encouraged. 



It is not as simple as that, for tiicrc are rea-<iris to lielieve that the grouse is not able to 

 make equallv good use of each of the foods whi( li it devours. Thornaj)ple and sumach seeds 



* Ont? kilogram rqiiaU spprniimalrly 2.2 pnunda. 



