AMERICAN OSPREY 353 



The changes in the distribution of the nesting birds during the past 

 50 3^ears, in the area covered by our obserA^ations, are also interesting. 

 AYhen our records began, in 1882, there were over 80 occupied nests 

 in the rather limited area that we hunted, on foot, in Rehoboth, See- 

 konk, and Swansea in Massachusetts and in Warren and Barrington 

 in Rhode Island. As time went on, we enlarged our field and dis- 

 covered a number of outlying nests in neighboring towns, both north 

 and south of the region named. The northernmost nest, north of 

 Taunton, was 18 miles from the nearest salt water ; and some of the 

 Rehoboth nests were 12 miles inland. The interesting point is that 

 these inland nests have been gradually disappearing, until now not 

 one of the 81 nests recorded in 1882 is in existence. The ospreys are 

 now all concentrated near the shores of Mount Hope and Narragansett 

 Bays and their tributaries. What caused this wholesale evacuation is 

 a mystery. Considerable egg collecting was done in certain parts of 

 the area, but no more than, if as much as, in the area where the birds 

 still breed. There are just as many suitable trees as ever, and many 

 perfectly sound nesting trees have been abandoned. There may be 

 fewer fish in the inland ponds and streams, though there has been no 

 noticeable increase in pollution. The only answer seems to be that 

 the birds have decreased in numbers, from some unknown cause, and 

 tlie remaining birds are concentrated where there is a better food 

 &upply and where they are more rigidly protected. In the area that 

 we now cover, there are between 50 and 60 pairs of birds nesting, 

 where there were at least twice that number 50 years ago. Formerly 

 we could visit between 30 and 40 breeding pairs in a day on foot, but 

 now our best recent record is 56 pairs seen with the help of an auto- 

 mobile. 



Spring. — Throughout all the northern part of its range the osprey 

 is migratory. In much of Florida and in the Gulf States the osprey 

 is present all winter, but C. J. Pennock tells me that it is absent from 

 northern Florida, Wakulla County, "from about the middle of No- 

 vember until early February." Arthur T. Wayne (1910) says that it 

 is absent from South Carolina "from December until very late in 

 February." Mr. Pennock's earliest date for Delaware is March 16. 

 In southern New England, the ospreys appear with considerable 

 regularity during the last week in March ; my earliest date is March 

 15, but Forbush (1927) has a record for March 7. Usually only a few 

 individuals are seen here in March, the main body arriving during 

 the first week in April. The males are said to precede the females. 

 Tlieir migrations are probably influenced by the movements of the 

 fish on which they prey; we usually see them at about the time that 

 the alewives, or herring, are starting to run up the rivers. In othei 

 parts of the country, their arrival is equally subject to climatic and 



