frigate bird ( F reqata maqnif icens ) ; 

 and (2) those dependent on the ter- 

 restrial food chain such as the red 

 shouldered hawk ( Buteo lineatus ), 

 barred owl ( Strix varia ), burrowing 

 owl ( Speotyto cunicularia ) , and 

 turkey vulture ( Cathortes aura ). 

 The parasitic jaeger ( Stercorarius 

 parasiticus ) is an occasional visi- 

 tor to the Keys (Woofenden and 

 Schrieber 1973). Its habit of 



stealing food from other birds 

 (terns and gulls), like the magnifi- 

 cent frigate bird, places it in this 

 category. Several species of this 

 guild that breed on the mainland 

 portion of the study area do not do 

 so in the Keys. These include the 

 black vulture ( Coroqyps atratus ), 

 red-tailed hawk ( Buteo jamaicensis ), 

 screech owl ( Otus asio ), and great 

 horned owl ( Bubo virqiniatus ) 

 (Robertson and Kushlan 1974). 



As with the terrestrially de- 

 pendent birds of prey, the arboreal 

 land birds of the Keys are limited 

 by available habitat. Only 20 to 25 

 breeding species are recorded from 

 the Keys (Robertson and Kushlan 

 1974). Table 49 summarizes the 

 records of breeding bird species in 

 selected Keys habitats. 



The most common land breeder is 

 the black-whiskered vireo ( Vireo 

 altiloquus ) which breeds exclusively 

 in the mangroves, according to 

 Sprunt (1954). The white-eyed vireo 

 ( Vireo qriseus ) is described by 

 Sprunt (1954) as a subspecies "may- 

 nardi" commonly known as the Key 

 West vireo. All of the birds listed 

 in Table 49, except the cardinal and 

 the ground dove, are insectivores 

 feeding off of the abundant insect 

 productivity of the Keys. 



9.36 MAMMALS 



Layne (1974) lists 13 species 

 of land mammals from the Florida 

 Keys (Table 50). The general south- 



Table 49. 



Breeding land birds in 

 the Florida Keys (adapted 

 from Robertson and Kush- 

 land 1974). 



ward decline in suitable terrestrial 

 habitat is generally regarded as the 

 primary reason for the relative pau- 

 city of species. This is particu- 

 larly obvious for the bats which are 

 represented by only two species 

 whose presence is at best doubtful. 

 The lack of freshwater as well as 

 the absence of caves severely limits 

 the group's invasion into the Keys. 



Mammals of the Keys exhibit a 

 high degree of endemism. As noted 

 in Table 50, 8 of the 16 species and 

 subspecies recorded occur only on 

 the Keys. Three of these 8 are sub- 

 species of one species, the raccoon 

 ( Procyon lotor ). One of these 3, the 

 Key Vaca raccoon, is considered 

 endangered. Three other endemic 

 subspecies, the Cudjoe Key rice rat 



218 



