Pheasants and Hungarians 113 



This behavior must be interpreted in the light of the fact that both State and 

 private plantings have continued more or less regularly for many years. No final 

 appraisal is possible until renewals have been discontinued, and experience has 

 shown whether the stock persists without renewal. Meanwhile there is no way 

 to interpret the central Illinois behavior except to consider it as intermediate be- 

 tween colony failure and full establishment. In all probability the stock would 

 gradually disappear but for the new plants made from time to time. 



Most of central and northern Indiana shows the same behavior as central 

 Illinois. 



Southeastern Minnesota seems to represent the equivalent case of artificial 

 establishment of Hungarians. There is a more or less thrifty Hungarian popula- 

 tion, but plants have been continuous since 1926. Colonies of drift birds have 

 crossed the Mississippi and established themselves in Wisconsin. In spite of this 

 favorable evidence, however, southeastern Minnesota does not present convincing 

 evidence of territorial aggression and increasing density. If the plantings should 

 cease it is possible that the stock would gradually disappear. 



Full Establishments. The denser hatching on Maps 10 and 11 shows the 

 areas on which full establishment has apparently taken place. These areas of es- 

 tablished range are not yet stable. Thus the Wisconsin establishment of both 

 pheasants and Hungarians is clearly moving westward. The Ohio establishment 

 of Hungarians has been moving northward into Michigan since 1918 or before. 

 The Indiana Hungarians seem to be spreading westward at one spot in Clinton 

 County at the western apex of their range, and this is coincident with a shrinkage 

 on the south side and prominent expansion on the north side of the Indiana 

 range. The Iowa-Minnesota Hungarians are spreading northwestward, as in- 

 dicated by the appearance of drift birds and outpost colonies in the Pipestone 

 Region of Minnesota. There may also be an eastward movement, but this has 

 been masked by the recent Minnesota plantings. The pheasants of northern Iowa 

 are still spreading eastward and slightly southward. 



In most of these established ranges it is possible to find comparatively dense 

 populations sometimes approaching one bird per acre, and apparently maintaining 

 this density over a period of years. Such densities are never attained in the 

 zone of artificial establishment farther south. Populations approaching the satura- 

 tion point, and maintained for a period of years, appear in fact to be characteristic 

 of established ranges, and to distinguish such ranges from lesser degrees of success. 



;.. .Interpretation. The foregoing captions describe the results of pheasant 

 and Hungarian plants in the north central region, but do not attempt to interpret 

 causes for their varying degrees of success. 



Certain miscellaneous findings on exotic populations will next be presented. 

 An attempt will then be made to infer possible causes, in the light of all the 

 evidence available, and to suggest what researches are necessary to prove or dis- 

 prove the inferred causes. It goes without saying that the cause of failure must 



