48 TWO ATLANTIC COAST ISLANDS 



Hawks that have yoimg * * *." To-day I estimate the 

 number at between one hundred and fifty and two hundred, 

 but the difference between these figures and those of 1812, 

 may be less real than one due to errors in estimate. In any 

 event, Gardiner's Island holds the largest Fish Hawk col- 

 ony in this country — possibly the largest in the world — and 

 the conditions under which many of the birds nest, offer ex- 

 ceptional opportunities for a study of their habits. 



Mr. Gardiner tells me that the Fish Hawks arrive on the 

 island, March 20, and depart on September 20. That the 

 same birds return year after year to the same nest, is be- 

 yond question, and, in at least one instance, this belief was 

 proven true by Mr. Gardiner's grandfather, who placed a 

 metal band on the tarsus of a Fish Hawk which, for many 

 subsequent seasons, was known to occupy a certain nest. 



Mr. Gardiner does not confirm current statements to the 

 effect that the Fish Hawks repair their nests in the fall ; 

 but in the spring there is much activity in nest-building, 

 even by birds whose homes are apparently already habita- 

 ble. The birds gather sticks from the ground and they also 

 break them from the trees by flying at or dropping on them 

 and grasping them with their talons. Eel grass is a favorite 

 nest-lining and the birds often fly about with four or five 

 feet of this grass streaming out behind like a long tail. 1 

 have never been on the island early enough in the season to 

 observe the mating habits of the Fish Hawks, but additions 

 to the nest are sometimes made after the eggs are laid, and 

 birds maj^ be seen with nest-material in June. 



The variation in the character of the nesting sites of 

 Fish Hawks on Gardiner's Island, effectively illustrates 

 how, under certain conditions, a bird may depart from the 

 habit of its kind, without paying the penalty which so often 

 befalls animals with but partially developed instincts. 



It is the normal habit of the Fish Hawk to nest in trees, 

 but on Gardiner's Island one finds these birds building their 

 homes not only in trees but actually on the ground. I do not 



