532 



SCIENCE 



[Vol. LV, No. 1429 



birds. The department hopes that counts will 

 be continued on all land where they have pre- 

 viously been made, and it especially desires to 

 obtain also series of counts indicating the bird 

 life on the plains ; on the deserts, both with and 

 without irrigation, and in the southern and 

 western states. 



It might be well to select new areas where 

 physical conditions are not likely to change 

 much for a number of years, so that if suc- 

 ceeding annual counts show changes in bird 

 population it will be known .that ' they are not 

 due to changed environment brought about by 

 man. On the other hand, there is much to be 

 learned regarding the adaptation of birds to 

 changes of environment; any area therefore on 

 which reports can be made year after year may 

 be chosen, even though conditions are likely to 

 change. Possible inability to repeat a count 

 on the same tract need not, however, deter 

 any one from making the count this year. 



The height of the breeding season should be 

 chosen for this work. In the latitude of Wash- 

 ington, D. C, at latitude 39 degrees. May 30 

 is about the right date for the first count. In 

 the latitude of Boston the work should not 

 begin until a week later; while south of Wash- 

 ington a date still earlier than May 30 should 

 be selected. The department wants to learn 

 how many pairs of birds actually nest within 

 the selected area. Birds that visit the area 

 only for feeding purposes must not be counted, 

 no matter how close their nests may be to the 

 boundary line. 



Several kinds of counts are needed for a 

 study of the relative abundance of birds under 

 changing and stationary conditions. It is 

 hoped that many persons interested in bird life 

 will make one or more counts this season. If 

 only one count is made, the tract selected should 

 represent average farm conditions for the 

 locality, should not have an undue amount of 

 woodland or orchard, and should contain not 

 less than forty acres a quarter of a mile square 

 nor more than eighty acres. If there is an 

 isolated piece of woodland of from ten to 

 twenty acres conveniently near, a separate 

 count of the birds nesting there will be useful 

 in addition to the count on the rest of the farm. 

 In this case the report, in addition to specify- 



ing the size and exact boundaries of the area, 

 should give the principal kinds of trees, and 

 whether there is much or little underbrush. 



A third count is desired of some definite area 

 of woodland, which is part of a larger timbered 

 tract. Still a fourth count, supplementary to 

 these is needed. The average farm in the 

 northeastern states contains about one hundred 

 acres, and the average count hitherto has been 

 of the birds nesting on the fifty acres of the 

 farm nearest to and including the farm build- 

 ings. It is now necessary to obtain counts also 

 of the remainder of the farm, the wilder part 

 containing no buildings, especially on the same 

 farms where counts about the buildings have 

 already been made. Besides these, counts on 

 any other kinds of land are much desired for 

 comparison. 



Anjr one who is willing to do this work is 

 recjuested to send his name and address to the 

 Biological Survey, Washington, D. C. Full 

 directions for making a count and report 

 blanks will be sent in time for plans to be 

 made before the actual time for the field work. 

 Since the bureau has no funds with which to 

 pay for this work, it must depend on the 

 services of voluntary observers. 



THE CHEMICAL EXPOSITION! 



The Eighth National Exposition of Chemical 

 Industries will be held this year in the Grand 

 Central Palace, New York, during the week of 

 September 11 to 16, inclusive. It will follow 

 immediately upon the fall meeting of the 

 American Chemical Society. The early date 

 will gi^'e college and university men an oppor- 

 tunity to see the exhibits before the beginning 

 of the college year. There is much in this 

 coming exposition to interest university men. 

 Each floor has exhibits of laboratory apparatus, 

 and one floor has a considerable group of this 

 type of equipment. Many new pieces of ap- 

 paratus, new chemical compounds, and other 

 material and instruments will be found here. 



The interests for industrial chemistry in the 

 exposition are wide and varied: from raw ma- 

 terials in ininerals, ores, manufacturing crudes 

 or by-products, through the range of ma- 



iFrom the Journal of Industrial and Engineer- 

 ing Ckeniistr)/. 



