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267 



Art. VI. — On the Tyrant Shrikes of America. 

 By William Swainson, Esq., F.R. and L.S. 



[Communicated by the Author.] 



There are few groups in zoology which may be termed more 

 truly natural, than those which are not only characterized by a 

 general conformity in the structure and economy of the indi- 

 viduals, but are further remarkable as being confined within cer- 

 tain geographic limits. The group of birds which may be typi- 

 cally represented by the Lanius tyrannus of Linnaeus, (and which 

 form the genus Tyrannus of M. Vieillot,) is one of the many 

 examples of these natural divisions in ornithology. They are 

 altogether natives of the new world, where they may be said to 

 represent the Drongo Shrikes (Edolius, Cuv.) of Africa and Asia. 

 The Tyranni are among those large insectivorous birds, who 

 seize their prey in the air, but only devour it when again at rest. 

 Like the true Shrikes, they are of a bold and quarrelsome dispo- 

 sition; unsocial and solitary in their habits, they will seldom 

 permit other birds to come within a certain distance of those 

 stations which they fix upon as their temporary throne. The 

 testimony of others concurs with my personal observations to 

 prove, that several of the larger species partake of those car- 

 nivorous habits which belong to the Thamnophilince. Indeed, on 

 one occasion, I took from the stomach of Tyrannus sulphuratw a 

 small species of lizard, which, however, was sufficiently large to ex- 

 cite astonishment that it ever could have been swallowed, in an en- 

 tire state, by a bird not larger than a thrush. The frequent oppor- 

 tunities which a residence in Brazil afforded me of observing the 

 habits of these birds, leads also to the belief, that they never use 

 their claws either for seizing their prey, or even for holding it, 

 when secured in the first instance by the bill. This supposition 

 is in some degree confirmed by the structure of the tarsi, which are 

 comparatively short, and much too feeble for such purposes ; the 

 claws are nevertheless very acute, and are probably used as offen- 

 sive weapons against other birds much larger than themselves, 



