26 The Ottawa Naturalist. [May 



enough to have stocked the continent, at any rate to the limit 

 of economic safety, had they been adapted to present conditions. 

 The Bluebird population was almost entirely wiped out one 

 winter. Fewer were left of them than of pigeons just after the 

 Petosky rookery was deserted; yet in five years the Bluebird 

 regained its old numbers. But the Bluebird is a strong, virile 

 race, suitably adapted to the conditions of a cultivated country. 

 The pigeon was not; hence it passed away while its close rela- 

 tive, the Morning Dove, still thrives and increases. 



It must be borne in mind that our bird population is limited 

 by natural conditions. In most cases this limit was reached 

 long ago, and no more birds can inhabit North America than 

 can find support during the season of least food supply. In a 

 normal or stationary population, the death rate must equal 

 the birth rate or else the population ceases to be stationary. 

 The breeding season increases the population enormousl}^ and 

 one way or another this increase must be, and is, reduced to 

 the smaller supporting power of the land through winter. 



It is evident that this allows of a considerable margin of 

 reduction and shows that even quite considerable numbers can 

 be destroyed without interfering with the ultimate numbers 

 of the population and that the comparatively few individuals 

 taken by collectors cannot have an appreciable effect upon their 

 number. 



The professional collector has come in for popular abuse, 

 far beyond his deserts. In the first place, the professional 

 collector is almost an unknown quantity. He is too scarce in 

 fact to find when wanted. In the next place, there is little or no 

 market for his wares. Few scientists are wealthy or able to pay 

 prices that allow the professional a livelihood. The trade in 

 big game heads and trophies with wealth v sportsmen is con- 

 siderable and the plumage business for millinery purposes has 

 wrotight devastation amongst certain species but the oppor- 

 tunities for professional scientific collectors are small indeed. 

 This is to be regretted as, allowing that the study of birds is 

 justifiable, it follows, as a matter of course, that the man who 

 supplies the material is justified also and is engaged in commend- 

 able work. No one person can personallv gather material from 

 ever^^where, yet extra-limital material is just what the serious 

 investigator requires in his work. Without a system whereby 

 the earnest student can, at least partially, pay the expenses of 

 his explorations, modern science would still be in the dark con- 

 dition of middle ages. The epoch making field works of Bates 

 or Wallace would have been impossible if they had not found a 

 market for their wares. 



