84 BULLETIN 135, UNITED STATES NATIONAL MUSEUM 



Egg dates. — New England and New York: 30 records, May 12 to 

 July 1; 15 records, May 23 to June 5. Illinois: 22 records, May 18 

 to June 16; 11 records, May 25 to 31. North and South Dakotas: 

 11 records, June 5 to July 21; 6 records, June 7 to 17. California: 

 11 records, April 21 to June 25; 6 records. May 23 to June 21. 



IXOBRYCHUS EXILIS EXIUS (Gmelln) 

 LEAST BITTERN 



HABITS 



This pretty little bittern, the most diminutive of the heron tribe, 

 is a summer resident in most of the United States and southern 

 Canada. Messers. Dickey and van Rossem (1924) have recently 

 given a new name, Ixohrychus exilis hesperis, to a larger race of this 

 species inhabiting the western United States and Lower California. 

 It is probably more widely distributed and commoner than is gener- 

 ally supposed, for, on account of its quiet, retiring habits it is seldom 

 seen and less often heard by the casual observer. Like the Virginia 

 and the sora rails, it sticks steadfastly to its chosen home in the inner 

 recesses of the dense cat-tail and reedy marshes; even when some 

 small piece of marsh is making its last stand against the encroachments 

 of civilization, the bitterns and rails may still be found there, attend- 

 ing strictly to their own business, coming and going under the cover 

 of darkness and unmindful of their outside surroundings. I can 

 remember three such bits of marsh, near the centers of cities in Massa- 

 chusetts, in which the rails and bitterns continued to breed until 

 they were driven out as the marshes were filled. 



Thus this quiet, retiring, and seemingly timid bird may Uve its 

 listless life almost within our midst and without our knowledge, unless 

 we choose to invade its home in the oozy bog, to wallow in mud and 

 water and to push through the forest of cat-tails and reeds. There 

 we may catch a glimpse of it, as it flops feebly away just over the 

 tops of the reeds or, if we stand and watch, we may detect a gentle, 

 swaying motion in the rushes, as a strange object appears which was 

 not there before, like a dry and yellow flag, tapering to a long sharp 

 point above and fading into the rushes below; now it stands stiff and 

 still like the surrounding flags; but if we stare at it long and hard, 

 we can see tAvo bright yellow eyes watching us and can make out the 

 distorted form of a bird, the hiding pose of the least bittern. How 

 well it matches its surroundings, how well it knows that fact and 

 how well fitted it is to survive among the tall, slender reeds and flags, 

 one of nature's triumphs in protective mimicry! 



Nesting. — The nesting habits of the least bittern vary considerably 

 in various parts of its range, where it adapts itself to the conditions 

 it finds in different kinds of swamps. The commonest type of nest 

 found in Massachusetts is built in the tall, dense growths of cat-tail 



