°'i9i8 ] Harlow, Breeding Birds of Penna. and N. J. 19 



full data are given for each nest found. My field work has 

 covered most of southern New Jersey from Mercer County and 

 the Hackensack marshes to Cape May; and a majority of the 

 counties of Pennsylvania, although the northwestern part of the 

 state has not been studied as thoroughly as the other portions. 



It has been thought best to consider all of the species given by 

 Dr. Stone as possible breeders giving my data for such as I have 

 found nesting and my reasons for regarding others as no longer 

 breeding within our limits. 



All the data presented are the result of my own studies except 

 in a few cases where credit is given to others and in a few species 

 which I have been unable to find breeding but whose nests others 

 have found. 



1. Podilymbus podiceps. Pied-billed Grebe. — Regular but scarce 

 summer resident in the Hackensack marshes of northern New Jersey. 

 Very rare summer resident in Pennsylvania where birds have been observed 

 in the nesting season in Franklin, Sullivan, and Center Counties and the 

 Cuckoo-like mating call heard. I have found four nests: 1. Newark, 

 N. J.; June 6, 1908; five newly hatched young and one egg. 2. Newark, 

 N. J.; June 6, 1908; six eggs. 3. Scotia, Center Co., Pa.; May 14, 1917; 

 six eggs. 4. Scotia, Center Co., Pa.; July 10, 1917; six hatching eggs. 

 Nests 3 and 4 were the product of the same pair of birds. 



2. Gavia immer. Loon. — I know of but one instance of the Loon 

 nesting in Pennsylvania or New Jersey, a nest found by Mr. Chas. Homan 

 in May, 1908, near Bushkill, Monroe Co., Pa., which contained two eggs, 

 (cf. Harlow, Auk, 1908, p. 471.) 



3. Larus atricilla. Laughing Gull. — Regular breeder on the 

 marshy islands on the coast of New Jersey, from Ocean Co. southward, 

 and apparently holding its own. Data on fifty nests give: average set of 

 eggs 3 (2-4); average date June 6 (May 25- July 15). 



4. Sterna hirundo. Common Tern. — Regular breeder along the 

 coast of New Jersey, where it is slowly increasing in numbers. I have 

 breeding records from Ocean to Cape May Counties. Data on twenty-five 

 nests give: average set of eggs 3 (2-4); average date, June 10. 



5. Sterna antillarum. Least Tern. — After being practically 

 exterminated on the New Jersey coast this species is beginning to reestab- 

 lish itself. I have found two small colonies in Burlington County and at 

 the time of my last visit, in 1916, they were holding their own. Data on 

 seventeen nests give: average set of eggs, 3 (1-2); average date, June 12. 



6. Rynchops nigra. Black Skimmer. — Practically extinct in New 

 Jersey until 1910 when two pairs were found on the coast islands of Atlantic 

 County. Since then I have found two or three pairs present every year 



