Sandwich terns breed in large colonies in the northern Gulf of Mexico and 

 sparingly farther north. They winter in much smaller numbers on the Florida coast of 

 the Gulf of Mexico: most of the population migrates south into the Caribbean. 



The common tern group does not fit a pattern, as it is composed of one species 

 that is a rare summer resident, another that is an uncommon breeder and common 

 wintering bird in the Gulf of Mexico, another that is an uncommon migrant and wintering 

 bird, and a fourth that is an accidental migrant. Roseate terns breed in small numbers in 

 the Florida Keys, while Forster's terns breed uncommonly in the northern Gulf of Mexico 

 and winter commonly on the coast of the Gulf of Mexico. Common terns are uncommon 

 migrants and wintering birds, and arctic terns are accidental in the Florida Keys and very 

 rare as migrants off the east coast of Florida. 



Turtles 



Four taxa of turtles were encountered in aerial surveys (Table 6). Loggerheads 

 were conspicuous in Florida survey subunits but were infrequently sighted in Texas. The 

 endangered Kemp's ridley was sighted only in Texas, and there in low numbers. 

 Leatherbacks were evident but in low numbers in Florida. Green turtles of various size 

 classes can resemble members of all other sea turtle taxa except the leatherback, so 

 many turtles could not be identified to species. 



The preponderance of turtles in Florida in relation to Texas possibly reflects two 

 facts. First, Florida includes nesting beaches for three marine turtle species 

 (loggerhead, green, and leatherback turtles). Second, the species of primary importance 

 in the western Gulf of Mexico, Kemp's ridley, has been severely reduced over the last 

 four decades. Although all species present in the Gulf of Mexico are historically known 

 from the Texas coast, surveys over an annual cycle may be necessary to elucidate the 

 degree of utilization of the area by marine turtles. 



SEASONAL VARIATION 



Mammals in STEX 



The frequency of sightings of mammals in the South Texas survey subunit declined 

 by 33.3% from August to November (Table 7). Of the nine taxa seen in August, only 

 three were noted in November. Bottlenose dolphins, which were not observed in August, 

 accounted for 71.4% of the sightings in November. Short- finned pilot whales were noted 

 during both STEX surveys. Dolphins of the genus Stenella were conspicuously absent 

 from observations in November. 



The absence of records for bottlenose dolphins in STEX during August is paralleled 

 by observations made in transit along the coast between Corpus Christi and Brownsville. 

 Bottlenose dolphins were not observed during flights paralleling the Laguna Madre and 

 adjacent onshore waters of the Gulf of Mexico even though these included the shallow 

 depths near the coast that are frequented by bottlenose dolphins throughout the range of 

 the species. 



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