492 Recent Literature. ^^^^ 



generalizations here presented indicate that certain facts and conditions, 

 of which experienced field ornithologists may feel conscious, may eventually 

 be established on a scientific basis. 



Professor Forbes points out that from the data thus far collected it is 

 evident that there is a numerical increase in birds from the northern part 

 of the State southward, in the ratio of 133 birds in the central part, and 

 181 in the southern, to 100 in the northern part. While there is undoubt- 

 edly a southward numerical increase, it must be noted that here June in 

 the south is compared with August in the north, which is hardly a fair 

 basis. It would hence be of interest to repeat the reconnaissance, revers- 

 ing the order. This would furnish a basis for the double comparison of 

 north with south — in June and Avigust — and for comparing two cen- 

 suses of the same region at opposite ends of the breeding season. As is 

 well known, August is the season of moult, when birds are comparatively 

 quiet and seek seclusion, and when, in the latitude of northern Illinois, 

 there is generally a dearth of birds in comparison with June. Some indeed 

 have either begun to move south, or have gathered into loose flocks and 

 are of irregular distribution, and some even occupy different haunts as 

 compared with June. Again, in repeating this reconnaissance in inverse 

 order in respect to season, it would be w'ell — almost important — to employ 

 the same observer as before, since different observers differ greatly in the 

 matter of expertness, and in the taking of such a census all the conditions 

 should be as similar as possible. 



The statistics presented respecting the Meadowlark are of exceeding 

 interest, but we do not feel so sure that the inductions based thereon are 

 satisfactory. It is of interest to know that there are many more Meadow- 

 larks apparently in southern Illinois than in northern Illinois, but the 

 greater abundance in pasture lands in northern Illinois in August as 

 compared with their numbers in meadows, than in southern Illinois in June, 

 may be in large part seasonal, since the preferred nesting grounds of Mead- 

 owlarks are meadows, while later in the season their dispersal is more 

 general and includes pasture and other open lands as well as meadows. 



If w'e were to make any formal criticism on Professor Forbes's paper, it 

 would be to say that while the work here reported upon is well worth 

 doing, and has been well planned, the data from a single season's work of 

 two observers are too few to warrant the expectation that generalizations 

 from them can be otherwise than premature, since observations made in 

 August in northern Illinois, cannot be satisfactorily compared with 

 others made in June in southern Illinois, since the two periods relate to 

 two very different seasons in the cycle of avian activities. — J. A. A. 



Warren on Birds of Northwestern Colorado.' — An itinerary, illustratetl 

 with a map, is given of the author's route in northwestern Colorado in 

 the spring and summer of 1907. Although the main purpose of the 



1 Northwestern Colorado Bird Notes. By Edward R. Warren. The Condor, 

 Vol. X, pp. 18-26, Jan. 1908. 



