occurs (regularly, as a native taxon) in multiple nations, but breeds in a single nation
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (250-20,000 square km (about 100-8000 square miles)) Breeding range is restricted to coastal mangrove areas of Florida, U.S., from the Florida Keys north to Volusia County on the Atlantic coast and Levy County on the Gulf coast. Winters from central Florida south; some may winter in the West Indies. Disjunct from D. D. DISCOLOR, which occupies most of the eastern United States, south to northern panhandle of Florida.
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, B.L. Sullivan, C. L. Wood, and D. Roberson. 2012. The eBird/Clements checklist of birds of the world: Version 6.7. Downloaded from http://www.birds.cornell.edu/clementschecklist/downloadable-clements-checklist
Differs from subspecies DISCOLOR in being much paler overall with grayish back; males lack the wide black markings on side and reddish backs (Bent 1953); also larger (A. Buerkle is conducting a comparative morphological and genetic study).
Comments: Closely associated with mangroves; some may inhabit stands of scattered live oaks (Quercus virginiana) near the coast. In Key Largo and nearby islands in Florida Bay, black mangrove comprised 70-100% of woody vegetation (Prather and Cruz 1995). Sometimes-occupied habitats include open, shrubby upland areas containing wax myrtle and saltbush (Prather, pers. comm.), red mangroves, and live oaks along coastal strands (Stevenson and Anderson 1994). Nesting occurs in black and red mangroves, buttonwood, and saltbush, 0.3-4 m above ground, with 40-60% cover in the nest area (Prather, pers. comm.). Average nest height in the Florida Keys was 1.6 m (Prather and Cruz 1995).
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 6 - 20
Density was highest (0.8-1.3 pairs/ha) on keys in Florida Bay, relatively low (0.3 pairs/ha) on mainline keys and Sanibel Island. Singing males are less common on the Florida mainland (Prather, pers. comm.).
Predators appear to be racoons, rats, snakes, and other birds (Prather and Cruz 1995). Cowbird parasitism may be significant; an individual recently was seen feeding a young cowbird in Everglades National Park.
Life History and Behavior
Singing begins in mid-late January. Nesting continues from late April (or earlier) through June (or later) (Prather and Cruz 1995). Several clutches of 2 eggs have been reported (Stevenson and Anderson 1994). Prather and Cruz (1995) found that mean clutch size was 2.86 (31% of nests had 2 eggs). There was a high hatch failure rate (12% of 83 eggs). Incubation period averaged 12 days, brooding period averaged 11 days (Prather and Cruz 1995). Fledging success was 46%; predation was the major cause of nest failure.
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: T3 - Vulnerable
Reasons: Subspecies endemic to Florida and dependent upon a habitat that is threatened by increasing development.
Other Considerations: This warbler is one of the few species of land birds almost entirely restricted to mangroves during the breeding season.
Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable
Comments: Destruction of mangroves for real estate development is the major threat facing this warbler. The range is becoming increasingly fragmented; considerable habitat has been lost north of Miami and Tampa. Competition with Cuban yellow warblers, first noted in Florida in 1941, poses a secondary threat. Predation appears greater where human influence is higher (more racoons, rats (Prather and Cruz 1995)). Brood parasitism by two species of cowbirds (brown-headed and shiny), their ranges recently extended into south Florida, poses a potential threat (Prather, pers. comm.). Shiny cowbirds are important brood parasites in Caribbean mangrove habitats. Pesticide pollution is also likely (Stevenson and Anderson 1994).
Biological Research Needs: The first nesting study of subspecies PALUDICOLA was recently published (Prather and Cruz 1995), but much remains unknown (e.g., whether it is permanently territorial, and whether it interacts with migratory populations). More life history information is needed before an effective management program can be designed. Also, genetic distinctiveness needs to be assessed (A. Buerkle is currently conducting genetic study). The possibility of interspecific territoriality with Cuban yellow warbler should be investigated.
Global Protection: Few to several (1-12) occurrences appropriately protected and managed
Comments: Occurs in Delnor-Wiggins Pass SRA, Collier-Seminole SP, John Pennekamp Coral Reef SP, Lignumvitae Key SBS, Long Key SRA, Mound Key SAS, Key Deer NWR, and Great White Heron NWR, Florida, USA.
Needs: Protect mangroves through legislation and aquisition. Give full refuge status to several EOs. Ban/limit pesticides.
Names and Taxonomy
Comments: Phylogenetic analyses of sequences of mitochondrial and nuclear DNA (Lovette et al. 2010) indicate that all species formerly placed in Dendroica, one species formerly placed in Wilsonia (citrina), and two species formerly placed in Parula (americana and pitiayumi) form a clade with the single species traditionally placed in Setophaga (ruticilla). The generic name Setophaga has priority for this clade (AOU 2011).