Restoration Potential: Recent conservation efforts and the establishment of national park lands and other protected areas in the Bahamas and Caribbean where hunting pressure has been high should help ensure the survival of this species. Recovery of this species will not be possible without continuing efforts to conserve existing habitat, throughout its range. However, habitat conservation will not always be sufficient to facilitate population recoveries. In the U.S. Virgin Islands there has been no open season since 1960, and nesting areas are now protected, but the near-complete destruction of mangrove nesting habitat leaves little hope for a substantial recovery of populations (Wiley 1985). Restoration projects that improve and expand mangrove nesting habitat and foraging areas will certainly benefit this species. Efforts underway to restore ecological function to the Florida Everglades may yield benefits for this species.
Preserve Selection and Design Considerations: Primary considerations for preserve selection are protecting coastal mangroves and islets suitable for breeding and protecting the remaining large patches of tropical hardwood hammock forest from further destruction and fragmentation. Habitat destruction in the Florida Keys and mainland has increasingly fragmented suitable nesting and foraging habitat.
Most nesting habitat is protected by the Everglades National Park, but loss of foraging habitat is a continuing threat to the Florida population (Strong et al. 1991). Conservation of fragments of at least five hectares (12 acres) is a priority. Large fragments (5.01-20 ha) make up less than 15% of the available habitat on the mainline keys, yet are preferred sites for dispersing young pigeons (Strong and Bancroft 1994a, Bancroft et al. 1992). Priorities for conservation and acquisition of important tropical hardwood forest in Florida are on Key Largo (especially the southern portion where only 17% of available habitat is protected) and other mainline keys.
However, habitat protection alone may not ensure the persistence of this species (Strong and Bancroft 1994). The distribution of habitat patches also appears to have significant importance. Larger forest tracts must be available near nesting areas to provide safe areas for post-fledging dispersal of immature birds. Habitat protection for dispersing young on the Florida mainland appears relatively sufficient as most birds were found within currently protected areas.
Extensive foraging habitat is also protected within the Everglades, but foraging areas closest to most nesting islands are on the mainline Keys and in Florida Bay where significant islands of suitable habitat are surrounded by water or development and are increasingly threatened. These locations are especially important to young pigeons as they are used as primary foraging locations for dispersing young and bases for dispersal to even more isolated patches of forest (Strong and Bancroft 1994b). Reproductive success is at least partly dependent on the availability and geographic location of larger, less fragmented habitats. Because most nesting areas are islets, young birds must fly from their nesting area over water to reach a suitable foraging area. In Florida, young dispersing from breeding grounds in the upper keys dispersed in two different directions, some to the mainline keys and others to the Florida mainland (Strong and Bancroft 1994). Young dispersing for the first time showed a preference for forest fragments 5-20 ha in size, and secondarily those .06 to 5 ha in size, and avoided urban areas altogether (Bancroft 1992, Strong and Bancroft 1994). The distance between the larger hammock patches has been shown to influence the successful dispersion of young pigeons (Strong and Bancroft 1994a).
Because White-crowned Pigeons are important for medium- and long-distance seed dispersal, their conservation will contribute to the conservation of the tropical hardwood hammock forest community in general (Terborgh 1986). Strong and Bancroft (1994b) suggest that conservation efforts should begin with protection of a network of relatively large forest fragments that would allow movement of this and other species of seed-dispersing organisms between large protected areas in the northern and southwestern portions of the mainline keys. Bancroft et al. (1992) suggest that a network of protected fragments that form "stepping stones" between the nesting keys and large tracts of forest habitat may be important for maintaining a viable population. Such a system would also provide a mechanism for dispersal and gene flow of plant species which would facilitate recolonization of plant species following hurricanes.
Management Requirements: HABITAT: In Florida and throughout the range of this species proposed elimination and alteration of any extensive stretch of coastal mangroves or mangroves islets should subject to careful review for impact to this species (Bancroft 1996). Locally, much can be done to maintain adequate food supplies by maintaining fruiting tree species in and around urban areas. Fig (FICUS spp.) trees are often are removed from residential areas because their extensive root systems interfere with septic systems. Poisonwood (Metopium toxiferum) is also removed because human contact with its sap causes severe itching (Scrulock 1987, Bancroft et al. 2000). Preservation and/or planting of poisonwood in urban areas may significantly benefit White-crowned Pigeon populations because of the availability of poisonwood fruit appears to determine how successful a nesting season will be. Blolly (Guapira discolor) and strongbark (Bourreria ovata) are also important food supplies and should be encouraged in suburban areas (Bancroft 1992).
HUNTING: In many Caribbean countries, hunted for subsistence or as a game species. Sport hunting in Caribbean countries has traditionally taken place during the breeding season when the birds are most predictable in locality. Where numbers of this species have declined significantly, reducing the season lengths or temporarily suspending hunting seasons seem a necessity. In addition, they are easily mistaken for Scaly-naped Pigeons (Columba squamosa) so, if hunting for Scaly-naped Pigeons is permitted, some White-crowned Pigeons will also be killed (Wiley 1985). Maintaining viable populations is also in the interest of hunters and the governments of these countries(Owre 1978). Interest from ecotourists and birders visiting these countries indicating their desire to see these birds along with the economic benefits of these visitors may influence the formulation of protective policies. Because most Florida White-crowned Pigeons spend part of the year outside the United States, the hunting policies of Caribbean countries may directly affect the population of birds breeding in Florida.
Monitoring Programs: Inadequately sampled by the BBS to extrapolate population trends. In addition to the methodology developed by Strong et al. (1994), the National Audubon Society has conducted a number of studies on the White-crowned Pigeon. Using a standardized counting methodology they obtained a thorough population estimate for the area east of a line running from Long Key to Cape Sable (does not include the Lower Keys) in 1991. Boat-based counts at nesting/roosting sites have been conducted. Road-based surveys were conducted between 1986 and 1991 using the BBS technique. The National Audubon Society's Christmas Bird Count has a limited ability to monitor wintering populations.
Management Research Needs: Research is needed on the effect of hydrologic changes on mangrove habitat structure in Florida Bay and how this may affect pigeon breeding. (Science Subgroup 1997).
Biological Research Needs: Better information is needed on: basic demography and causes of local population fluctuations; critical nesting and foraging habitats; movement patterns and winter distribution of large nesting populations and how this varies within and among years; habitat trends (Owre 1978, Bancroft 1992, Bancroft and Bowman 2001).
Two major facets of the ecology of Florida white-crowned pigeons remain to be studied (Bancroft 1992). First, little is known about the ecological requirements of birds on their wintering grounds. Second, more understanding of the factors that affect survivorship of adults and juveniles may be critical for the development of management plans to maintain a healthy breeding population of this bird in Florida. (Bancroft 1992).
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