28 CIVIC BIOLOGY 



determine the species as far as possible, indicating them by 

 some device, like the initial letter of the name, on the plat. 

 This work should be completed as soon as possible after the 

 leaves fall in November. By inquhy it may be possible to 

 locate nests that have been " collected " or destroyed by storms 

 during the summer. This will give a " census " of the bird 

 population of the tract. 



The main question which this investigation is designed to 

 answer is, Are there enough birds in the area to hold the 

 insects in check ? To aid in answering this question examine 

 the district minutely for evidences of insect depredations, and 

 make a list of important insect pests found upon it. Examine 

 at least 100 of each variety of apple, pear, quince, possibly 

 peach and plum, and tabulate the percentage of the different 

 fruits injured by insects. Gather similar data, if possible, for 

 the earlier fruits, strawberries, gooseberries, currants, and 

 also for the. various garden vegetables and other crops grown 

 in the tract. Add to the bill of damage the cost of materials, 

 apparatus, and labor expended in righting insects. On the 

 other side of the balance sheet record with equal care any 

 injury caused by birds. Note what kind of birds caused the 

 damage. 



From all you know and can learn of bird life try to discover 

 what special features attract the birds to nest on the tract, 

 water, food, suitable nesting sites and materials. Suitable 

 and accessible water for drinking and bathing will be found 

 to be one of the main factors, and food supply and absence 

 of enemies, other elements. Never lose an opportunity to see 

 what a bird is doing, what it is searching and finding for food. 

 Clear observation on this point seldom fails to answer the 

 question, Why is the bird here ? 



Study with equal care all the elements which can account 

 for a scarcity of birds or the absence of particular species. 

 What necessities of bird life are lacking? What natural 



