BIRDS OF THE CAMBRIDGE REGION. 105 



sounds to which many other creatures, much less wary but also less discriminat- 

 ing, never become accustomed. Thus although it has ceased to frequent cer- 

 tain of our ponds which it used to visit regularly, it resorts to others oftener and 

 in decidedly greater numbers than it did thirty or even sixty years ago. In 

 Fresh Pond, for example, but few Black Ducks alighted between 1832 and 1840, 

 according to information which I have received from Mr. J. Elliot Cabot, while 

 most of those which occurred there during my own early experience merely 

 passed overhead on migration although the pond then had extensive, reedy coves 

 which attracted other kinds of surface-feeding water-fowl. No doubt the Black 

 Ducks of those days knew full well that they were closely watched by ambushed 

 gunners, and equally without doubt the birds of the present time have observed 

 that shooting is no longer regularly practised at Fresh Pond ; for although its 

 coves have been filled, its beds of reeds obliterated, and a broad, much fre- 

 quented driveway carried around its entire margin, one is now nearly sure of 

 finding Black Ducks in this pond almost any day between the middle of August 

 and the date when the water freezes over. They usually arrive in the early 

 morning and spend the day near the middle of the pond where they float or 

 paddle idly about, preening their plumage or sleeping in perfect security. The 

 railroad trains which dash noisily along the eastern shores do not seem to alarm 

 them, and they pay no attention whatever to the carriages and bicycles that tra- 

 verse the parkway drive, but the report of a gun, however distant, will often 

 cause them to rise suddenly and leave the pond. They invariably depart at 

 nightfall, either on migration or for more or less distant feeding grounds. 



Their numbers vary greatly from day to day and from month to month. 

 In August it is unusual to see more than ten or a dozen at any one time ; in 

 September, more than twenty or thirty ; in October, more than seventy-five or 

 one hundred ; but in November and December one may frequently count over 

 one hundred and occasionally as many as two hundred and fifty. Most of the 

 birds present in late November and in December, remain in our immediate 

 neighborhood through the entire winter, visiting the pond by day whenever 

 it is free from ice ' and feeding by night in the tidal creeks and marshes near 

 Lynn and Revere. Of these wintering Ducks the greater number, without 

 doubt, belong to the form rubripes. Indeed we are often able to make out the 

 chief distinguishing characters of this large northern race when the birds are 

 swimming or flying near at hand. There can be little doubt that true obscnra 

 also occurs in winter, since it has been found sparingly at that season at Ipswich 

 and elsewhere along the Massachusetts seacoast. To what extent its times of 



' On several occasions they have been seen in some numbers, standing or lying on the ice, after 

 the pond was almost completely frozen over. 



