NOETH AMERICAN MARSH BIRDS 93 



Egg dates. — Southern New England and New York: 30 records 

 May 20 to June 23; 15 records, May 29 to June 11. Michigan 

 and Wisconsin: 32 records, May 27 to Julyl; 16 records, May 30 

 to June 12. liUnois: 35 records, May 22 to July 10; 18 records. May 

 30 to June 21. Florida: 22 records, March 25 to June 26; 11 records, 

 April 26 to June 5. 



ARDEA OCCIDENTALIS Audubon 



GREAT WHITE HERON 



HABITS 



The Bay of Florida, including Barnes Sound, which is really a part 

 of it, is a practically triangular body of water, approximately 35 miles 

 long and 25 miles wide, bounded on the north by the southern coast 

 of Florida, from Cape Sable on the west to the entrance to Black- 

 water Bay on the east, bounded on the south by the outer line of 

 keys, and open on the west toward the Gulf of Mexico. Through- 

 out its whole area the water is exceedingly shallow, averaging not 

 over 3 feet in depth: the bottom is covered with white, soapy, slimy 

 mud, which makes the water generally turbid and mostly opiique. 

 At low tide many square miles of mud flats are exposed, leaving only 

 an intricate maze of winding channels open to navigation in shallow 

 draft vessels, and even at high tide a thorough knowledge of the chan- 

 nels is necessary to avoid running aground in a boat drawing over 

 2 feet of water. 



The outer keys, forming the southern boundary, are mostly of 

 coral formation and were probably the first to appear, inclosing an 

 area in which mud and sand has accumulated and made possible the 

 formation of the mangrove keys with which the whole interior of the 

 bay is thickl}'- studded. The inner keys are nearly all of the mangrove 

 type, though many of the larger and older ones have now accumu- 

 lated sandy beaches and considerable solid, dry soil. Their origin, 

 however, is directly traceable to the agency of the red mangrove and 

 all stages of their development can be seen in process of formation. 

 The red mangrove drops its seed into the water, where it floats away 

 until its long tail strikes root in some shallow place ; as the tree 

 grows, its spreading branches are constantly reaching outward and 

 downward to take root again, until a dense thicket or "bush," as it 

 is called, is formed; this increases steadily in size, soil is eventually 

 accumulated in its center, where the red mangroves finally die out 

 and are replaced by black mangroves growing in muddy soil; as the 

 soil becomes drier by continued accumulation, the black mangroves 

 are again replaced by other tree and shrubs, glowing on dry land and 

 often forming dense thickets; on some of the largest and oldest keys, 

 open grassy plains have been formed with only scattering trees or 

 clumps of bushes around their borders. 

 92642— 2Gt 8 



