BULLETIN FLORIDA STATE MUSEUM


nation may be that these young sites usually were adjacent to active min-
ing operations. Consequently the areas were not open to the public and
were completely closed to waterfowl hunting, resulting in little human
disturbance to the birds. Another possible reason may involve a more
dense or higher quality food source than in older pits.
 In a parallel with the distribution of oldfield mice, there appeared to
be a distinct bird community on Young Tiger compared with birds on the
two younger sites in this class, Shark Tooth and Big Teeth. Young Tiger
had 42 species present during the year, compared with 27 and 24 respec-
tively for the other two. In addition, the other diversity and abundance
figures showed comparable differences (Tables 7-10). The higher bird
community measures may be explained by the more advanced stage of
plant succession supported by Young Tiger. Indeed, certain passerine
species, such as palm warblers, savannah sparrows, boat-tailed grackles,
and red-winged blackbirds, were consistently more abundant on the Young
Tiger site than on the other two. However, much of the difference in
species composition resulted from the high number of wading and water
birds found at Young Tiger. This is more likely tied to some difference in
food supply, water quality, or water levels than to terrestrial plant succes-
sion on the exposed spoil piles. We lack the data to evaluate the impor-
tance of these or other factors. In any case, it appears that in terms of
bird communities the arbitrary age category of 0-5 years may be mis-
leading in that the first major increase of bird diversity and abundance
may occur in 3 years after mining. This statement is based on the data
from only one site; however, qualitative observations on other young pits
in the area tended to support that view.
 The 5-15 year old treatment was similar in species composition to
Young Tiger, but with the increase in vine and shrub cover we found
additional species of resident passerines, including white-eyed vireos,
cardinals, and blue jays. In addition, several species of winter residents,
such as yellow-rumped warblers and house wrens, were rare in the 0-5
year class but abundant in the 5-15 year sites. Undoubtedly the shrubs
and vines provided good cover for both wintering and nesting species,
but perhaps even more important was the use of wax myrtle berries for
food during the winter months. This became more apparent in the older
sites but was readily observed here.
 Wading birds were still quite common in this class, and increased
shoreline and littoral vegetation provided habitat for king rails and soras.
However the only ducks using these sites consistently were blue-winged
teal.
 The 15-30 year old pits and those >30 years old with lakes showed
quite similar species composition and diversity measures (Fig. 19). Per-


VOL. 30 NO. 3