668 



DR. J. C. MOTTEAM ON" SECONDARY 



alike, and perhaps the duck might be considered to he a non- 

 diver, but E. C. Stuart Baker in ' Indian Ducks ' says " it is a 

 most expert diver." 



The Marbled Duck [Marmaronetta angustirostris) forms a like 

 exception, but has unusual habits, which to a large extent 

 protect it from enemies. It never goes ashore ; it remains 

 nearly always in rushes. The Andaman Teal {Nettion alhigulare) 

 is another, but this bird is an insular species and is said to be 

 entirely nocturnal. 



However, examples more difficult to account for are to be 

 found ; for instance, the Whistling Ducks {Dendrocygna). These 

 birds have arboreal habits, and at a sign of danger take to the 

 trees. On the whole, therefore, although at first sight appa- 

 rently serious exceptions, on more detailed examination ducks 

 are found to fall into line with the rule that diving-birds exhibit 

 less secondary sexual difierences than non-divers. 



Very few, if any, birds can entirely escape from hawks by 

 means of rapid flight (arboreal birds are to some extent free 

 from their attacks). Two of the favourite quarries of the 

 Eastern hawkers are teal and sand-grovise, among the most i-apid 

 fliers. There ai-e, however, a few birds which are able by , 

 means of skilful dodging to evade the attacks of hawks — for 

 instance, the hoopoe, of which Finn says " it is easily able to 

 escape from hawks." 



Table VI. 



Notes. — Compiled from P. Finn's ' The World's Birds.' 



Honey-Guides are not eaten by natives because they are useful in guiding them 

 to honey ; Humming-birds possibly because of their small size. Puff-birds 

 are doubtfully described as presenting " sometimes sexual differences," as 

 shown in the following table compiled from P. L. Sclater's ' Bucconida?' : — 



? a. sl.d. 



Puti'-birds 33 8 2 



? = no note made as to whether sexes are different or not. 



As regards Trogons, other works have been consulted but with no result. 

 Keference Nos. :— 1 edib. 2, 9, 22, 25, 29, 30, 32, 35, 36, 43, 45, 46 : 2 edib. 7, 20, 



33, 37, 39, 42 : 3 edib. 11, 23, 47 : 4 edib. 5, 14, 16, 19, .34, 41 : 1 non-edib. 



1, 4, 6. 8, 13, 17, 18, 28, 40, 48 ; 2 non-edib. 3, 10, 12, 15, 26, 27, 31, 44, 50 : 



3 non-edib. 21, 28 : 4 non-edib. 24, 49. 



