BULLETIN FLORIDA STATE MUSEUM


ably Mimus polyglottos. Crotophaga is obviously an omnivore (see Ap-
pendix III), Tyto preys on birds and rodents, and Coereba is chiefly a
nectarivore. Considering the small populations of Tyto on these islands,
an apparently adequate food supply, and the absence of a competitor,
the breeding season of this owl should not a priori be restricted by either
a wet or dry season. Crotophaga is more abundant, occurring in scat-
tered but small and discrete groups in many ecological formations; be-
cause of its omnivorous habits, it too would hardly be restricted in
breeding by wet or dry seasons. Perhaps a similar argument could be
made for Mimus, but less is known of this species' annual cycle. Coereba
is an interesting case, because throughout its range in the Caribbean re-
gion it is renowned for a protracted breeding season. In the absence of
hummingbirds (at least for the Cayman Islands) this Bananaquit can
utilize a unique food resource (nectar and tiny insects) to support a
large and widespread population at all seasons.

 INTER-ISLAND DISTRIBUTIONAL PATTERNS
 Archipelagos are renowned for their interrupted distributional pat-
terns among the avifauna. In this context, examples are found in indi-
vidual species of Galapagos finches (Geospizidae) and Hawaiian honey-
creepers (Drepaniidae). However, patterns above the family level, al-
though often well known for a given archipelago, have largely been over-
looked in the literature, and since the Cayman Island avifauna contains
conspicuous examples of distributional "anomalies," an analysis of these
distributional patterns is discussed here and summarized in Table 14.
 One is faced, of course, with the obvious question-why is species A
restricted to a given Cayman island and yet species B, whether a con-
gener or not, occurs on all three islands? At the outset, several basic
premises must be recalled and at least temporarily accepted: (1) the
three Cayman islands are of a similar geological age; (2) with relatively
minor exceptions (introduced logwood and its scattered stands limited to
Grand Cayman), ecological formations or habitat structures appear to be
identical, or nearly so, among the three islands (see previous discussion);
(3) the three islands are each approximately the same distances from
both Cuba and Jamaica, the potential if not actual sources of most of the
avifauna; (4) Grand Cayman has a much greater land area than the
smaller islands, and certainly the areal expanse of each ecological forma-
tion is far greater on the larger island; and (5) there is no evidence that
hurricane tracks or wind or water currents are extraordinarily restricted
to any one of the islands.
 Pertinent to these disjunct distributions are the statements by White-
 head and Jones (1969: 176): ". . if one assumes that the rate of move-


Vol. 19, No. 5