dicate that the physiological utilization of calcium by 

 hens on the Illinoian drift was similar to that by hens 

 on the VVisconsinan drift. 



Even if soils on the Illinoian drift contained less 

 available calcium than the soils on the Wisconsinan drift, 

 the difTerence might be compensated for by the apparent 

 ability of pheasants to be selective in the type of grit they 

 consume. Sadler (1961:340-341) found that penned 

 hen pheasants selected calcareous grit (limestone) rather 

 than noncalcareous grit (granite) during the egg-laying 

 period. Harper (1963:365-366; 1964:269) reported that 

 wild pheasants in Illinois, both young and adults, selected 

 calcific over dolomitic grit, as well as calcareous over 

 noncalcareous grit. Also, pheasant hens may possess the 

 ability to select calcitic grit containing high rather than 

 that containing low levels of calcium (Harper & Labisky 

 1964:730). 



Native gallinaceous birds, the bobwhite and the 

 prairie chicken [Tympanuchus ciipido), counterparts of 

 the pheasant, have established self-maintaining popula- 

 tions on areas of Illinoian drift in Illinois. These birds, 

 like the pheasant, have high calcium demands. 



Our conclusion is that, in Illinois, calcium is as avail- 

 able to pheasants on Illinoian glacial drift as on Wis- 

 consinan drift, which is of more recent origin. We found 

 that hen pheasants and young pheasants in areas of Illi- 

 noian drift ingested calcium in amounts similar to the 

 amoimts ingested by birds in areas of Wisconsinan drift; 

 also, that the physiological utilization of calcium by hen 

 pheasants in an area of Illinoian drift appeared to be 

 equal to that by hens from a thriving population of 

 pheasants in an area of Wisconsinan drift. It seems un- 

 likely that, in Illinois, the establishment and maintenance 

 of pheasant populations in areas of Illinoian glacial drift 

 are prevented by a deficiency of calcium. This con- 

 clusion, however, does not disprove Leopold's hypothesis 

 that a deficiency of some element or vitamin may pre- 

 vent the establishment of pheasants on areas of pre- 

 Wisconsinan glacial drift. 



Pheasants and Weather 



Weather, as well as a deficiency of calcium, has long 

 been regarded as a factor limiting (i) the southward 

 spread of the pheasant, particularly in the eastern portion 

 of the United States, and (ii) the abundance of pheas- 

 ants within portions of their established range. Pheasants 

 have become widely established in the northern sectors 

 of the midwestern and eastern United States, but, with 

 few exceptions, they have failed to establish self-main- 

 taining populations south of a line designating 40 degrees 

 north latitude. 



Of the many stimuli or stresses to which the pheasant 

 is subjected, some of the most important are associated 

 with weather. The description Selye (1949:837) gives 

 of the "stage of resistance," the second stage of the 

 general-adaptal ion-syndrome, indicates that a pheasant 

 hen is capable of adapting to one or more stresses but 

 at the expense of resistance to others. The description 

 of the "stage of exhaustion," the third and final stage 



of the syndrome, indicates that the hen may die as a 

 result of very prolonged exposure to stresses to which she 

 has become adapted; the hen cannot indefinitely main- 

 tain adaptation to certain stresses. Even stresses that 

 do not cause death may interfere seriously with the 

 physiological functions of the hen, particularly those asso- 

 ciated with reproduction. \'ery likely, the stresses that 

 weather exerts on the pheasant are fewer, less intense, 

 less prolonged, and less critical in the established con- 

 tiguous range of the bird than in range where the bird 

 experiences difficulty in maintaining even meager, dis- 

 junct populations. 



Extensive losses of pheasants as a result of unfa\or- 

 able weather conditions in winter are well documented 

 in the Plains and Prairie States. AVinter losses of pheas- 

 ants as high as 90 per cent have been reported in p)ortions 

 of South Dakota (Kimball et al. 1956: 211, 229 i ; severe 

 winter losses have been reported in Iowa (Scott & Baskett 

 1941:28), Minnesota (Erickson et al. 1951:33-34) 

 North Dakota (Miller 1948:4-5), and Nebraska (Mc- 

 Clure 1948:268-269). These reported losses of pheas- 

 ants during winter in the Plains and Prairie States were 

 attributed mainly to the birds' freezing and choking dur- 

 ing severe winter storms— storms characterized by heaw 

 snowfall and strong winds. That starvation is probably 

 not an important cause of winter mortality was demon- 

 strated by Tester & Olson (1959:308-309), who re- 

 ported that, in Minnesota, pheasants penned out-of-doors, 

 aitliough losing considerable weight, could sur\-ive at 

 least 2 weeks without food during severe winter weather. 

 The cases of star\ation reported by Nelson & Janson 

 (1949:308) in South Dakota were confined to small, 

 scattered areas; only about 5 per cent of the pheasants 

 in these areas died from starvation. 



Losses of pheasants to winter weather in the Lake 

 States, which include Illinois, are usually much less severe 

 than in the Plains and Prairie States because prolonged 

 ]3criods of deep snow and low temperatines are less 

 frequent, and food in the form of waste gi-ains is gen- 

 erally abundant (Fig. 5, 6) . 



E\en though winter weather is seldom so se\ere as 

 to cause direct losses of pheasants in the Lake States, 

 and [jarticularly in Illinois, imfavorable weather condi- 

 tions during winter may so weaken the birds physio- 

 logically that they enter the breeding season in less dian 

 adequate physical condition. Kozicky et al. (1955:140) 

 pointed out that in Iowa '"two months of consecutive 

 low tempcratmcs from December through Fcbruaiy were 

 detrimental to fall pheasant populations by reducing the 

 breeding stock." Recently, Edwards, Mikolaj, & Leite 

 (1964:278'! suggested that depressed reproductive per- 

 formance of pheasants \vas directly related to low body 

 weights resulting from exposvn-e of the birds to severe 

 weather during the preceding winter. This promising 

 area of investigation— the relationshi]) between winter 

 weather and rcjiroduction — merits attention in future 

 ]iheasant research. 



Rainfall and temperature, particularly during the 

 breeding season, ha\c long been considered two of the 



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