100 BIRDS OF A MARYLAND FARM. 



SHRIKES. 



The impaling of grasshoppers and mice by the loggerhead shrike 

 {Lanius ludovioiarms) near the storage barn has already been men- 

 tioned (see p. 64). The only other field observation was on Octo- 

 ber 23, 1901, when a shrike near the same place was seen to kill a gar- 

 ter snake {Eutainia) 13 inches long. Owing to the small number of 

 shrikes at Marshall Hall no specimens were taken, but in order to 

 investigate the feeding habits some experiments were carried on with 

 a captive bird given me by Mr. William Palmer. The habit the bird 

 has of impaling prey has been the subject of considerable speculation, 

 some writers maintaining that it gibbets its victims alive for the 

 pleasure of watching their death struggles, and others that it slaugh- 

 ters more game at a time than it can eat and hangs up the surplus to 

 provide against a time of want. This theory of prudent foresight 

 may explain why it kills more game than it can eat, but, as the experi- 

 ments showed, it does not touch the real reason why it impales its 

 prey. 



On the day after the shrike in question was captured a dead mouse 

 was offered it. The shrike raised its wings, moved its tail up and down 

 petulantly after the manner of the phoebe, and then seized the mouse 

 and dragged it about for several minutes, trying to wedge it into first 

 one and then another corner of the cage. Failing in this effort, it tried 

 to impale the mouse on the blunt broken end of a branch that had been 

 placed in the cage for a perch, but the body fell to the floor. Then it 

 tried to hold the mouse with its feet and tear it to pieces, but its feet 

 were too weak. A nail was now driven into the cage so as to expose 

 the point. Immediately the shrike impaled its prey, fixing it firmlj^, 

 and then fell to tearing and eating ravenously. Several days later the 

 nail was removed and a piece of beef was given to the shrike. By dint 

 of hard work it managed to hold the beef with its feet, so that it could 

 bite off pieces; but it much preferred to have me do the holding, when 

 it would perch on my wrist and pull off mouthf uls in rapid succession. 

 These experiments indicate that the shrike is unable to tear to pieces 

 food that is not securely fixed. Hawks can grip their food with their 

 powerful talons and then easily tear it into pieces small enough to be 

 swallowed, but the shrike's feet have not a sufficiently vigorous clutch 

 to permit this method. 



A series of experiments in feeding insects to this shrike was also 

 carried out. If the bird was very hungry it did not impale insects. 

 When offered a grasshopper {Hipplscui) at such times, it would clutch 

 it with one foot, and, resting the bend of its leg on the perch, bite off 

 mouthfuls and swallow them. When not very hungry it impaled 

 grasshoppers and caterpillars {Sphinx catalpse). Such prey as the 

 thousand-legs, centipfedes (Lithobhis), house-flies, and blow-flies {Cal- 



