Economic Reasons for Protection 97 



As eight meadow mice have been found in 

 the stomach of a single marsh hawk, and as this 

 probably represented but a part of the day's 

 food supply, it would not be unreasonable to 

 suppose that each marsh hawk destroyed at 

 least eight mice or their equivalent in other 

 harmful creatures every day to supply its own 

 needs. But in order to be well within bounds 

 let us cut this number in two, and suppose that 

 each hawk kills but four meadow mice each day 

 — a number probably quite insufficient to keep 

 such a large, active bird in good condition. 

 This would mean that a pair of these hawks 

 would destroy eight mice in a day, or 2920 mice 

 in a year. It has been estimated that each 

 meadow mouse on a farm causes an annual loss 

 to the farmer of at least two cents, by destroying 

 grass roots, tubers, grain, and young fruit trees — 

 a very conservative estimate it would seem. 

 The destruction of 2920 mice then, would save 

 the farmer $58.40. In other words it puts into 

 his pocket $58.40, which but for the hawks would 

 have been eaten up by mice. Now, it is an 

 exceptionally good cow which gives an annual 

 return as large as that, and a farmer owning such 

 a cow would be very careful not to shoot her by 

 mistake for some harmful animal; yet that same 

 farmer will, without a moment's hesitation, 



