JOHNSTON: CAYMAN ISLAND AVIFAUNA


TABLE 2.-BIRDS OF FRINGING REEFS, LAGOONS, AND SAND-CORAL BEACH.

 Island: GC GC LC CB
 Species Date: December Apr-June August June-Aug
Phaethon lepturus C
Sula leucogaster U C
Sula sula VC
Fregata magnificens U FC VC FC
Ardea herodias U
Florida caerulea U U U
Hydranassa tricolor U
Pandion haliaetus U U
Squatarola squatarola FC U U U
Arenaria interpres FC U U U
Actitis macularia U U
Tringa solitaria U
Catoptrophorus semipalmatus U U
Larus atricilla FC U
Sterna hirundo FC
Thalasseus maximus C C
Ceryle al!con U
Hirundo rustica C
 Total species 13 10 7 5

least a temporary first landfall for migrants. Three breeding forms
(Elaenia martinica, Dendroica petechia, and Coereba flaveola) are com-
mon there throughout the year (Table 3). The very interesting Nycta-
nassa violacea, known locally as "crabcatcher," stalks small land crabs
(chiefly Gecarcinus lateralis and Cardiosoma guanhumi) on the ground
among the Coccoloba and Terminalia trees. Fruits of these and other
trees are important seasonal dietary items of Columba leucocephala and
both of the Zenaida species. In winter this formation supports at least
10 additional species of North American migrants, for the most part
foliage-gleaning warblers (Parulidae).
 BIRDS OF MANGROVE SWAMPS.-Although mangrove swamps differ
floristically according to the dominant plant species (Rhizophora mangle
or Laguncularia racemosa and Avicennia nitida or Conocarpus erectus),
as a whole this formation teems with bird life, especially in the winter
(Table 4). Noticeably high concentrations of North American warblers
(12 species) utilize mangrove swamps in the winter months (see later
analysis of the winter avifauna). Field observations of a non-quantita-
tive nature suggest that insect food supplies also peak at this season.
Even during the breeding season 10 bird species regularly inhabit this
formation, with Dendroica petechia being exceptionally common at all
seasons.
 BIRDS OF PASTURES AND CULTIVATED AREAs.-Pastures, grasslands, and
 cultivated fields are well-known for'relatively low densities of breeding