Our Livini^ Resources — Birds 



fi.i 



1991 is the similarity in adult-immature age 

 ratios during this interval (Fig. 2). Although 

 immatures could not be censused accurately 

 because they tend to wander individually or in 

 aggregrations alter the break up of family 

 groups, they are believed to have numbered 

 between 100 and 200 in any one year, giving a 

 total statewide population of 400-300. 



The estimate of the minimum adult popula- 

 tion includes single adults observed in an area 

 only once during a 5-year interval as represent- 

 ing a pair on an established territory. Assuming 

 that such individuals were actually unmated 

 transients reduces the estimated adult popula- 

 tion to about 230 individuals. Regardless of 

 which estimate of the adult population during 

 1972-91 is accepted, it is highly unlikely thai 

 the Florida population was reduced to fewer 

 than 100 birds between 1967 and 1970 

 (Heinzman 1970). 



Although the range of Audubon's crested 

 caracara in Florida appears to have remained 

 unchanged for the past 60 years and numbers 

 have been stable over at least the past 20 years, 

 the future status of the population is still of con- 

 cern. Most birds occur on private ranchlands 

 subject to habitat degradation or loss from 

 intensification of agricultural practices or other 

 development. The most immediate threat is 

 large-scale conversion of native range and 

 improved pasture habitats to citrus groves. 



A decline in the Florida caracara population 



within the next 10 years appears likely if citrus 

 conversion and other habitat losses continue at 

 the present rate. Because caracaras are relative- 

 ly long-lived and strongly attached to their ter- 

 ritories, residents may persist in a territory 

 despite unfavorable changes, but may not be 

 replaced by new individuals when they finally 

 leave or die. The result may be a significant 

 time lag before the effects of deleterious habitat 

 changes are reflected in an actual population 

 decline. The magnitude of the time lag in detec- 

 tion of any trend in the Florida distribution and 

 population of Audubon's crested caracara also 

 will depend upon the effectiveness of future 

 monitoring effoils. 



References 



Federal Register. 1987. Endangered and threatened wildlife 

 and plants: threatened status for the Florida population of 

 Audubon's crested caracara. Federal Register 

 52(l28):25229-25232. 



Heinzman. G. 1970. The caracara survey, a four year report. 

 Flonda Naturalist 4,^:149. 



Howell. A.H. 1932. Florida bird life. Florida Department of 

 Game and Freshwater Fish. Tallahassee. 479 pp. 



Layne. J.N. 1978. Audubon's caracara {Caracara cheriuay 

 aiiihihani). Pages _^4-.^6 in H.W. Kale II. ed. Birds, rare 

 and endangered biota of Florida. Vol. 2. University Press 

 of Florida, Gainesville. 



Layne, J.N. Audubon's crested caracara il'iilvhuriis plaiicus 

 amluboiiii). In J. A. Rodgers. H.W. Kale II, and H. Smith, 

 eds. Birds, rare and endangered biota of Florida. 2nd ed. 

 University Press of Florida, Gainesville. In press. 



Sprunt. A., Jr. 1954. Florida bird life. Coward-McCann, 

 New York. .'i27 pp. 



300.^ 



250- 



^200- 



T3 

 CD 



°150- 



6 



CU 



1 100- 



to 

 UJ 



50 



53% 



55% 



61% 





72-76 77-81 82-86 87-91 

 Year 



Fig. 2. Estimated numbers of 

 adult Audubon's crested caracaras 

 in Florida over -"i-year intervals 

 from 1972 to 1991 . based on the 

 assumption that localities where 

 adults were recorded represent ter- 

 ritories occupied by an adult pair. 

 Percentage of locations that had 

 immature birds versus those that 

 had adults are given above bars. 



For further information: 



James N. Layne 



Archbold Biological Station 



PO Box 2057 



Lake Placid. FL 33S62 



Since the airival of Columbus in Puerto Rico, 

 the Taino Indian has disappeared and the 

 panot has just barely survived (Wadsworth 

 1949: Snyder et al. 1987). The Puerto Rican 

 parrot (Amazomi vituita) had shared its habitat 

 with the peaceful Taino Indians for centuries 

 before the airival of European settlers in the 

 Caribbean. 



Status and Trends 



Upon arrival of the Spanish in 1493. the 

 Puerto Rican parrot lived in all major habitats of 

 Puerto Rico and the adjacent smaller islands of 

 Culebra, Mona, Vieques, and possibly the 

 Virgin Islands (Snyder et al. 1987). Parrots 

 occupied eight major climax or old-growth for- 

 est types (Little and Wadsworth 1964) that cov- 

 ered Puerto Rico and were interspersed only by 

 small, scattered, sandy, or marshy areas near the 

 coast ( Snyder et al. 1987). Parrots nested in cav- 

 ities of large trees that were plentiful throughout 

 the forests. Fertile, moist lowland forests in the 

 coastal plain as well as forested mountain val- 

 leys contained much of the fruits and seeds nec- 



essary to feed a thriving panot population. The 

 forests of Puerto Rico probably supported a par- 

 rot population of 100,000-1.000.000 at the end 

 of the 15th century (Snyder et al. 1987; Wiley 

 1991). 



Little habitat change occurred in Puerto Rico 

 during the first 150 years of European settle- 

 nient. By 1650 the Spanish population had 

 increased to 880 (Snyder et al. 1987); parrots 

 still occupied all major habitats and were plen- 

 tiful (Fig. 1 ). During the next two centuries the 

 human population soared to almost 500,000 

 (Fig. 1). and clearing for agriculture, especially 

 in the lowlands, eradicated forests in Puerto 

 Rico (Wadsworth 1949). By 1836 reports by 



Puerto Rican 

 Parrots 



by 



J. Michael Meyers 

 National Biological Service 



1500 



1600 



1700 1800 

 Year 



1900 



2000 



Fig. 1. Population trends of 

 humans and Puerto Rican parrots 

 since 1500 (Snyder et al. 1987 and 

 U.S. Census data; all data for the 

 year 2000 are projected). 

 Populations are converted to logj^ 

 for showing trends. 



