BIRDS OF PENNSYLVANIA. i'31 



Family LARID^E.* The Gulls and Terns. 



14. Rissa tridactyla (Linn.). 



Kittiwake. 40. Accidental winter visitant H. B. Graves mounted a 

 specimen taken in Lancaster county. 



15. Larus argentatus smit hsoniamis Coues. 



American Herring Gull. 51ti. This bird is said to be a common spring 

 and fall migrant on Lake Erie. It occurs also on the Delaware river 

 and occasional!}' is observed about the large streams in the interior. 



16. L. delawarensis Ord. 



Ring-billed Gull. 54. This species is frequently met with during the 

 spring and fall migrations in different parts of the State. It is also 

 found on the Delaware river in winter. 



17. L. atricilla Linn. 



Laughing Gull. 58. Found on the Delaware river, and occasionally in 

 the interior during the spring and fall migrations. 



18. L. Philadelphia (Ord.). 



Bonaparte's Gull. 60. Migratory. Said to be quite common during spring 

 and fall migrations on Lake Erie. Not uncommon on the Delaware 

 river and in the interior. 



19. Oelochelidon nilotica (Hasselq.). 



Gull-billed Tern. 63. Very rare. H. B. Graves killed a specimen in 

 Chester county in the autumn. 



20. Sterna tschegrava Lepech. 



Caspian Tern. 64. A specimen mounted by Mr. Joseph Krider is said to 

 have been captured in Delaware county. 



21. S. maxima. Bodd. 



Royal Tern. 65. In September, 1879, H. B. Graves shot a specimen in 

 Berks county. 



22. 8. forsteri Nutt. 



Forster's Tern 69. Specimens are sometimes taken during spring and 

 fall migrations. 



23. S. hirundo Linn. 



Common Tern 70. Specimens are often taken during migrations, especi- 

 ally in September. 



24. 8. paradiscea Brun n. 



Arctic Tern 71 Specimens are occasionally taken in the autumn about 

 the rivers. 



*These birds occur ia Pennsylvania chiefly as stragglers. When found inland they usually are 

 observed after severe wind and rain storms. None, as far as I am aware, breed in the State. 

 The Gulls and Terns are found principally about the coasts. Certain species, however, frequent 

 large inland waters. Although there are exceptions, it may be stated in a general way that 

 Gulls are larger than Terns. In Gulls the bill ishooked, while in Terns the bill isstraight. Again, 

 in Gulls the tail is even ; in Terns the tail is forked. The Gulls are veritable scavengers of the 

 sea. They feed eagerly upon any and all kinds of animal food which may be cast into the waters 

 before them. They also devour pieces of bread, crackers and fruit which are cast overboard. 

 Nuttall says : " Like Vultures, they are voracious, feeding on every kind of animal food, 

 whether dead or living, fresh or tainted. The larger kinds also prey upon eggs and young 

 birds ; but their principal supply is fish, whose crowding shoals they follow with much eagerness, 

 seizing their prey with great address as it approaches the surface of the water, darting swiftly 

 in quest, and at the same time submerging the head. So powerful is the gastric juice in thia 

 family of birds that it suffices even to digest the scales of fish, feathers and putrid matter." The 

 Terns, when feeding, will frequently hover over the water, in the same manner as the Sparrow 

 Hawk does when hunting in a grass field, and dart head foremost into it, oftentimes with 

 such velocity as to submerge the whole body. Unlike the Hawk, however, which seizes its prey 

 in its talons, the Tern captures its prey in its bill. Dr. Coues, writing of the Terns, says : " The 

 larger kinds feed principally on little fish * * * but most of the smaller ones arc insectivor- 

 ous and flutter over marshy spots like Swallows or Nighthawks." Gulls and terns are web- 

 footed. They swim with great ease, but are, it is stated, unable to dive. 



