168 



THE CONDOR 



Vol.. IX 



insectivorous species. Dr. Beal heads the list 

 of beneficial birds of the forest with "The 

 Woodpeckers", as taking the lead in the well- 

 fare of tree life. The first colored plate shown 

 of this group, is of a Red-headed Woodpecker 

 at the end of a dead stub, a big brown and 

 yellow-edged grasshopper in its bill ready for 

 the gaping mouth of a young bird humped up 

 on the other side of the stub, in all anxiety and 

 expectation of that hopper. It is the most 

 happy thought for a plate, of the sixteen bird 

 groups, all by that great bird delineator of the 

 present day Douis Agassiz Fuertes. Other 

 plates show the Northern Hairy, White-backed 

 Three-toed and Black-backed Three- toed Wood- 

 peckers, the Yellow-bellied Sapsucker, and 

 male Flicker. Dr. Beal also mentions that the 

 Warblers, Vireos, Chickadees, Creepers, 

 Cuckoos, Orioles, Robins, Kinglets, Pine Gros- 

 beaks, Crossbills, Crows, and Blue Jays, all 

 play an important part as conservors of the 

 forest. Crows, Blue Jays, Crossbills and many 

 of the Woodpeckers perform a great part, in 

 the planting of tree seeds, which replenish the 

 forests. Birds of prey are also shown to be of 

 some benefit by keeping down the many 

 smaller mammals so destructive to young tree 

 growth. 



In the concluding article, "The Wild Fowl 

 of the St. Lawrence River", by J. W. Dunham, 

 are shown three colored plates by Fuertes, of 

 the Hooded Merganser, Pintail and Golden- 

 Eye; there are also nine half-tone plates of 

 nests and birds from life. Mr. Dunham gives 

 an account of the water fowl's habits, as they 

 occur on the St. Lawrence River, and mentions 

 such restriction as should be made to protect 

 them and other game of this river once so 

 famed for its wild fowl. — W. O. E. 



The Bulletin of the Illinois State Laboratory 

 of Natural History for April, 1907, pp. 305-335, 

 contains a very novel article by S. A. FoRBES, 

 Ph. D., which is entitled, "An Ornithological 

 Cross-section of Illinois in Autumn." 



The paper deals with the science of ecology, 

 or the relations of organisms to their environ- 

 ment, animate or inanimate. At the outset the 

 two terms, special ecology and general ecology, 

 are discriminated between, special ecology 

 being the ecology of one species, while general 

 ecolog}^ is the study of the ecolog}' of a whole 

 assemblage of species. Most work previously 

 carried on in this line has dealt with special 

 ecology. This article is given up to a discus- 

 sion of the general phase of the study in a truly 

 original manner. 



There has been carried on in the past, by the 

 Biological Survey and by various other labora- 

 tories, considerable study of the food habits of 

 various species of birds. Dr. Forbes conclu- 

 sivel}^ shows that the data in this line which 

 has been accumulated is not practically 



applicable until the relative mimbers and exact 

 distribution of each species are known. 



Two students were sent out by the Illinois 

 State Laboratory to traverse the state in various 

 directions, keeping accurate account of the dis- 

 tance traveled, birds seen, and crop areas passed 

 over. The trip considered in this paper was 

 made across the state from east to west in a 

 straight line, from Danville, near the Indiana 

 line, to Ouincy, on the Mississippi. The men 

 traveled 50 yards apart for the whole distance, 

 taking account of all birds seen within this 

 strip and 100 yards in front of them. Crops of 

 corn, wheat, clover, timothy, millet, fruit, and 

 timber were passed thru, and some pasture, 

 meadow, stubble, plowed ground, yard and 

 swamp lands were included in the strip. 



The most numerous bird was the English 

 vSparrow, 1620 of the 4804 birds seen belonging 

 to that species. In all, 92 species of birds were 

 observed, altho 85 per cent of the individual 

 birds seen belonged to 15 species. 



The bulk of the paper consists of tables of 

 numerical facts, worked out from the data 

 furnished by the two field observers. In these 

 tables every possible relation of each species of 

 bird to every other and to the various crops is 

 taken into account. 



In point of area corn was the principal crop, 

 with the area in pasture land and stubblefield 

 coming next. 



From the tables it is apparent that the 

 English Sparrow was the principal corn-field 

 species; the Meadow Lark was most abundant 

 in stubble fields and fields of young wheat; in 

 pasture land the English Sparrow was the com- 

 monest, with the Crow-blackbird a close second; 

 the Meadow Lark and Cowbird were equally 

 abundant in meadows; Horned Larks were most 

 numerous on plowed ground; while the ever- 

 present English Sparrow was most numerous 

 in orchards. 



By taking the ratio of the birds found in a 

 particular crop to the whole number of birds as 

 a dividend, and the ratio of the area in that 

 crop to the entire area as a divisor, the fre- 

 qiiency ratio of the bird and crop in question 

 is found. Then by dividing the frequency 

 ratios of a species for each crop b}' its frequency 

 ratios for all the other crops, the coefficients of 

 preference are obtained. 



The article closes with a table of the 92 

 species identified, with the numbers of each. 

 It is characterized thruout by the mathematical 

 precision with which the observed facts have 

 been recorded. A new and instructive line of 

 work is opened. It would certainly s-eem that 

 the true ecological significance of the birds of a 

 community could be gotten at in no surer or 

 simpler way than this. In place of general 

 inferences, results have been actually figured 

 out, accurately and graphically. — WALTER P. 

 Taylor. 



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