In the lower Keys, Osborn and 

 Custer (1978) identify 16 nesting 

 sites of herons and their allies 

 (pelicans and double crested cormo- 

 rants). Ten of these sites are 

 located along the outer northern 

 fringe of the small keys bordering 

 on the Gulf of Mexico. Table 48 

 summarizes the observed or estimated 



Species 



population levels at these nesting 

 sites in 1975 to 1976. It is obvious 

 from this table that the lower Keys 

 wading bird population is character- 

 ized by relatively few birds of all 

 species. An exception is the rose- 

 ate spoonbill which is completely 

 absent from the lower Keys, although 

 it does occur on the upper Keys. 



NESTING SITES 



TOTAL 

 NESTING PAIRS 



D 



1 



• 2 



o „ t 



Table 48. Estimated breeding pairs of wading birds in the lower keys 

 (adapted from Osborn and Custer 1978). 



Judging from the amount of in- 

 tertidal and shallow water habitat 

 available in the Keys, it seems 

 logical to expect significant, if 

 only transient, population numbers 

 of many species of probing shore 

 birds. The extensive shoreline, 



combined with washout of seagrasses 

 to form seawrack harboring an abun- 

 dant invertebrate food source also 



contributes to the apparent suitabi- 

 lity of the Keys for probing shore 

 bird use. 



Six species of probing shore- 

 birds are listed as breeding on 

 natural beaches and mudflats of 

 south Florida (Robertson and Kushlan 

 1974). These are the American oy- 

 stercatcher ( Haematopus palliatus ). 



216 



