12 THE WILSON BULLETIN— March, 1921 



after birth in our nidifugons young. I'rofessor Herrick has 

 intimated that the instinct of fear appears with comi)ar- 

 ative sudclenuess upon certain niatniity of the nervous 

 system, and while often premature, it is usually timed to 

 correspond with a sufficiently advanced physical develop- 

 ment to enable a retreat from threatened danger. It 

 would seem impossible to discover the precise time of the 

 acquisition of fear by the nestling, through the bungling 

 methods, or rather lack of method, of the past ; for fear 

 may be present and remain latent for hours or days before 

 an abrupt movement of the observer or tlie extreme nerv- 

 ousness of the parent lead to its discovery with startling 

 suddenness, and I believe it is always preceded by the ac- 

 quisition of sight. 



Instinctive fear has been shown on the fourth to the 

 fifth day by some of the Cuckoos and Sparrows: on the 

 fifth to the sixth day by the Least Bittern, Mockingbird 

 and Wren-tit; seventh to eighth day: Green Heron, Long- 

 eared Owl, some of the Mreos, Wood Warblers and Brown 

 Thrashers; tenth day: Mourning and Ground Doves, Ked- 

 shouldered Hawk, Cowbird, Catbird, Chickadee, Wood, 

 Hermit and Olive-backed Thrushes and Robin ; eleventh 

 day: Cedar Waxwing and Blue Jay; twelfth day: Marsh 

 Hawk and Crested Flycatcher ; fourteenth day : Turkey 

 Vulture, some of the Hummingbirds, Bluebird; sixteenth 

 day : Sharp-shinned Hawk ; twentieth day : Crow ; twenty- 

 first day : Anhinga, California Vulture, Duck Hawk and 

 Magpie; twenty-fifth day: Golden Eagle and Belted Kmg- 

 fisher; twenty-eighth day: Broad-winged HaAvk. TJie Yel- 

 low-billed Tropic-Bird, according to the experience of Mr. 

 Gross, never showed fear at any time. 



The production of more than one brood in a season 

 is rather rare among the ^"idifugie, the Grebes, some of the 

 Murrelets and Ducks, tlie Bob-whites and Scaled Part- 

 ridges, being among the few occasionally reproducing the 

 second brood. With the Nidicohp two or more families a 

 season are much less uncommon, though perhai)s not so 

 regular as generally su])])osed ; including, as far as known, 

 some of our most abundant and widely distributed species; 



