BULLETIN FLORIDA STATE MUSEUM


TABLE 5.-BIRDS OF PASTURES AND CULTIVATED AREAS.

 Island: GC GC LC CB
 Species Date: December Apr-May August June-August
Ardeola ibis C C FC U
Circus cyaneus U
Falco columbarius U
Falco sparverius U
Zenaida asiatica FC FC U
Columbina passerina FC FC* C* U*
Amazona leucocephala U U U
Coccyzus minor U U
Crotophaga ani C C* FC* FCO
Chordeiles minor UO U*
Tyrannus dominicensis C* U0
Mimus polyglottos C CO FC* U0
Dendroica palmarum VC
Quiscalus niger FC FC U
Dolichonyx oryzivorus U
Tiaris olivacea FC FC* U* U*
Passerina cyanea U
Melopyrrha nigra U
Passerculus sandwichensis U
Ammodramus savannarum U
 Total Species 16 9 7 8
* known or suspected breeders 5 5 6


this represents 63 percent of the breeding terrestrial avifauna for the
islands. Furthermore, during the breeding season the total population
in this formation exceeds that of any other formation on the islands, with
the exception of the town-house site-roadside formation. In winter, the
limestone forests clearly do not attract as high a contingency of North
American migrants as do the logwood, logwood-thatch palm-red birch,
and mangrove forests. This may be partially explained by the so-called
"irregularity principle," as discussed by Willis (1966), namely the
tendency for migrants in the tropics to avoid extensive forests but to
favor "irregular" or "peripheral" habitats, such as montane forests or iso-
lated areas or those disturbed by man.
 BIRDS OF INLAND LAGOONS AND PoNDS.-In winter and spring migra-
 tion periods, a large variety of birds is attracted to this formation (Table
 9). This is due to (1) the abundant food supply (small fish, crustaceans,
 etc.) and (2) varying water depths that can accommodate both small
 wading birds, such as sandpipers, and birds feeding in deeper waters,
 such as occasional diving ducks. The low but dense mangroves sur-
 rounding such ponds provide nesting sites for herons and egrets.
 BIRDS OF TowNs, HOUSE SITES, AND ROADSIDES.-Areas subjected to
 human disturbance generally possess such a great variety of plant species


Vol. 19, No. 5