Title: Ecology of a population of crocodylus acutus at a power plant site in Florida
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Permanent Link: http://ufdc.ufl.edu/UF00066433/00001
 Material Information
Title: Ecology of a population of crocodylus acutus at a power plant site in Florida
Physical Description: Book
Creator: Gaby, Ronald
McMahon, Mark P.
Mazzotti, Frank J.
Gillies, W. Neil
Wilcox, J. Ross
Affiliation: Pennsylvania State University -- Department of Biological Sciences
Publisher: Society for the Study of Reptiles and Amphibians
Publication Date: 1985
General Note: Drawn from Journal of Herpetology, Vol. 19, No. 2, pp. 189-198, 1985
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Bibliographic ID: UF00066433
Volume ID: VID00001
Source Institution: University of Florida
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Journal of Herpetology, Vol. 19, No. 2, pp. 189-198, 1985
Copyright 1985 Society for the Study of Amphibians and Reptiles

Ecology of a Population of Crocodylus acutus at a
Power Plant Site in Florida


'Connell Associates, Inc., Division of Environmental Sciences, 1320 So. Dixie Suite 700,
Coral Gables, Florida 33146, USA,
State : Department of -;: Sciences, Graduate Program in Ecology,
S . Park, .- ... .... 16802, USA, and
3Florida Power & Light Company, Environmental. *i... Department, P.O. Box 14000,
Juno Beach, Florida 33408, USA

ABSTRACT.-This paper presents the status and ecology of a population of Crocodylus acutus
associated with the Turkey Point power plant in Florida. Distribution, habitat preference, repro-
duction, population size and structure, and recruitment and dispersal are discussed.
Nesting occurs on spoil berms in the cooling canal system. The Turkey Point population con-
tributes 10% of the annual production of hatchlings in southern Florida. Crocodiles have exploited
previously unavailable, man-altered nesting habitat in approximately 4 years.
The resident population consists of a minimum of 19 adult, subadult and juvenile crocodiles.
This population exhibits differential habitat preferences according to size class, and shows seasonal
changes in distribution. Salinity regime is a factor in these trends. Ecology and population structure
are similar to those of the population residing in the more pristine habitat of Everglades National
Park. Long distance dispersal and recruitment into the Turkey Point population are documented.
The long-term outlook for the population in this man-altered habitat is for growth and expansion.

The American crocodile (Crocodylus
acutus) occurs in the estuarine swamps
of tropical South, Central, and North
America, and the Caribbean. Despite
this extensive distribution, its popula-
tion ecology remains poorly under-
stood, in part because the species is now
rare over most of its range. It is classi-
fied as endangered by the state of Flor-
ida, the United States Government, and
the International Union for the Conser-
vation of Nature (Federal Register 40:
44149, 1975; Federal Register 44:75074-
75076, 1979; Florida Game and Fresh
Water Fish Commission, 1978; Honeg-
ger, 1979; Groombridge, 1982).
The status of C. acutus in south Flor-
ida was assessed by various authors
(Moore, 1953; Powell, 1973; Ogden,
1978; King et al., 1982; Kushlan, 1982;
Jacobsen, 1983; Mazzotti, 1983). Since
most of Florida Power & Light Compa-
ny's Turkey Point Power Plant in Dade
County, Florida is within the bound-

aries of federally-designated Critical
Habitat of the American crocodile, we
undertook a series of :.: i:- aimed at
documenting the ecology and status of
the C. acutus population residing in and
around the cooling canal system. This
paper discusses aspects of the ecology
of the Turkey Point C. acutus popula-
tion: distribution, habitat preference,
reproduction, population size and
structure, and recruitment and dispers-
-I ... s (1983) studies, conducted
concurrently, were carried out in more
natural C. acutus habitat of Everglades
National Park, while our study took
place in a completely man-altered en-
vironment. A i> .... purpose of this
paper is the comparison of C. acutus
ecology in these radically different en-
vironments. The Basin Hills area of
north Key Largo, which also will be dis-
cussed for comparative purposes, rep-
resents an intermediate habitat; the


nesting areas are man-made, while
much of the :: .':.':: .habitat is unal-

The study was conducted at Turkey
Point, in southeastern coastal Dade
County, Florida, on property owned by
: Power & Light Company. The
comprises approximately 2830
h and is occupied by a closed-loop cool-
ing canal system serving two nuclear
and two fossil fuel generation units, and
a number of adjacent canals and roads.
The study area is bordered on the
northeast by Biscayne Bay and on the
southeast by Card Sound "., 1).
9- ...: .. of its latitude, low elevation,
and adjacent warm ocean currents,
southern Florida is considered to be cli-
matologically insular and subtropical
(Hela, 1952). Temperature conditions
are moderate with mean winter air tem-
peratures 70C lower than mean summer
temperatures. During the warmest
months of July and ,^ : -:;-'. diurnal air
temperatures reach about 320C. Despite
a moderate climate, no part of the Flor-
ida mainland is immune from cool tem-
peratures, and occasional frosts occur
(Mitchell and Ensign, 1926; Thomas,
1970). T- *-:-.-* the coastal areas are
warmer than the interior.
Rainfall is markedly seasonal with 60
to '. of the 115 to 140 cm annual pre-
cipitation falling in the May to October
period. The i ..: i...... of this rainfall
is bimodal with peaks in June and in
September-October (Beard, 1938).
Most of the study area was historical-
ly altered by excavation and *":.
Dates for the excavation of the various
systems at Turkey Point are as follows:
Model Land Canal East, 1940's; Sea-Dade
Canal, 1960; L-31E, 1967; moat, 1969;
cooling canal system, 1969-1974; Inter-
ceptor Ditch, 1974; C-107, 1976 (Fig. 1).
The :: canal system was complet-
ed in 1974; it is 8.2 km 1.... 4.2 km
wide, and consists of 32 discharge and
6 return canals totalling 270 km in
length. Each cooling canal averages 60
m wide and is shallow (0.5 m to 2 m

deep). Condenser ,.. 1 '.. water is dis-
charged into the northeastern corner of
the system and flows west, then south
at a rate of about 4.5 m/min. It is col-
lected at the south end of the system
and is returned to the plant intake
Of the 2430 h contained within the
cooling canal system perimeter, about
64% is water and about 36% is .
berm. These berms, which separate the
cooling canals, were created from ma-
terial dredged during canal construc-
tion. Berms : .:: from 1 to 5 m in
height and average 27 m in width, with
-...: -..- banks.
A number of canals adjacent to the
.::.: canal system (Fig. 1) are impor-
tant to the crocodile population. These
canals vary in depth, width and salini-
ty. Furthermore, some are confluent,
while others are separated by roads or
other terrestrial barriers.
The vegetation in the study area is
dominated by mangrove swamp which
consists primarily of red (: '. ;
S.... ." and white mangrove (Laguncu-
laria racemosa). The berms in the cooling
canal system support a wide variety of
vegetation, ranging from barren areas
interspersed with low-growing, salt-
tolerant species including glasswort
(Salicornia spp.), purslane (Sesuvium
spp.), saltwort (Batis maritima), to very
dense forested areas dominated by Aus-
tralian pine (Casuarina spp.), red man-
grove, and buttonwood (Conocarpus
erectus) in the canopy and sawgrass
(Cladium jamaicensis), swamp fern
. ... serrulatum) and saltbush :
charis spp.) in the understory.
.. .... grass (7.: .; maritima) is the
dominant aquatic plant in the cooling
canal system. Canal banks are vegetated
primarily by red mangroves in the sa-
line and brackish areas, and by sawgrass
and other freshwater emergents in the
freshwater portions.
Fluctuations in salinity (refractome-
ter, American ( .: Co.) and mini-
mum, maximum and ambient air and


FIG. 1. The Turkey Point power plant site.

water temperatures (min-max ther-
mometers, Brooklyn Thermometer Co.)
were measured at 3 stations in the cool-
ing canal system, 4 in the Interceptor
Ditch, 3 in Sea-Dade Canal, 3 in C-107,
2 in Model Land Canal East, 1 in the
moat, and 1 in L-31E. These stations
were monitored weekly from February
through December 1980.

Daylight crocodile surveys were con-
ducted between January 1978 and No-
vember 1982, using vehicles and boats.
Approximately equal survey effort was
expended in major areas of the site
throughout the study period. Diurnal
helicopter surveys were conducted dur-
ing the months of April, May, June and
November of 1978, February of 1979 and


1980, and August of 1980. During heli-
copter surveys an altitude of 50 to 80 m
and a speed of 80 to 100 km/hr were
maintained. On occasion, surveys by
boat or helicopter included the Barnes
Sound and north Key Largo shorelines.
Nocturnal surveys were conducted by
vehicle, airboat, jon-boat or canoe.
Crocodiles were located by their eye-
shine. Airboat use was confined to the
cooling canal system, while canoes and
jon-boats were used throughout the
study site. Since key portions of the
study site were accessible by road, the
greatest number of survey hours were
by vehicle.
Location, time, size (estimated to the
nearest 0.3 m), habitat and observations
of behavior were recorded each time a
crocodile was sighted.
Because the canal systems in the study
area are not all confluent, C. acutus cross
dry land areas to go from one canal sys-
tem to another. Sand was spread at
known crossing areas to document
tracking the movements of animals.
During each site visit observers record-
ed numbers, locations, and direction of
C. acutus movements.
Crocodiles were captured generally at
night because reflected eyeshine from
spotlights made them relatively easy to
locate. Crocodiles less than 1 m total
length were captured by hand or with
Pilstrom Tongs. Those animals larger
than 1 m total length were captured in
walk-through traps set at crocodile
. ... : locations with Kleflock self-
locking wire nooses, or noosed by hand
from a boat. To facilitate handling, the
crocodile's mouth was taped shut, and
the animal was tied with rope (Mazzot-
ti, 1983).
Total length and snout-vent length
were measured. Captured crocodiles
were weighed with Pesola (100 g, 1 and
2.5 kg) or Detecto hanging scales (1000
kg). When possible, the sex of croco-
diles greater than 1 m total length was
determined by probing the cloaca (Cha-
breck, 1963).
Monel poultry wing tags (National

Band and Tag Co.) were attached to the
middle web of the left hind foot. Num-
bered, plastic, cattle ear tags ( :..
were attached to the double row of tail
scutes and to either a herculite neck col-
lar or to a radio-collar around the ani-
mal's neck.
Location, time of capture, and habitat
descriptions were recorded for each
capture. For this study, C. acutus size
classes are defined as follows: juveniles
(60 cm to 120 cm), subadults (121 cm to
183 cm), and adults (greater than 183
cm). At the time of capture, salinity and
air and water temperatures were mea-
Transmitters (Model SB2, AVM In-
strument Co.) were used for tracking
and locating animals from July 1978
through September 1982. A total of four
adults, two subadults, and three juve-
niles were radiotagged during the
course of the study.
Transmitters and batteries were en-
capsulated in a solid block of plastic be-
tween belting layers. Each collar had a
30 cm external whip antenna. Trans-
mitters were individually identifiable by
frequency and pulse rate, and had a
range up to 1.6 km. Collars were se-
cured around the neck by two brass
bolts or two aluminum pop rivets which
corroded over time and allowed the col-
lars to fall off. To prevent anterior and
lateral movement, the collars were seat-
ed on the nuchal scutes using dental
acrylic (Mazzotti, 1983).
Signals were received with a
(164.125-164.700 mH,) LA12 telemetry
receiver (AVM Instrument Co.). A quar-
ter-wave omnidirectional or four-ele-
ment yagi directional antenna was used
for locating animals.
Temperature and Salinity.-Water tem-
peratures in the cooling canal system
were significantly (P < 0.0005) higher
than in any other canal system during
several months of the year. The highest
monthly average water temperature was
36.1C in the cooling canal system, while


the range of maximum temperatures in
all the remaining canal systems was be-
tween 30.60C and 33.3*C. For all systems
the maximum : - -. monthly water
temperature occurred in July.
Fig. 2 presents the summary of the
salinity levels measured in the canal
systems at Turkey Point during 1980.
The Interceptor Ditch (I.D.), L-31E and
the moat were generally freshwater,
Model Land Canal East (M.L.C.E.), C-
107, and Sea-Dade Canal (S.D.C.) were
moderately brackish to saline, and the
cooling canal system (C.S.) was gener-
ally saline to hypersaline.
Reproduction.-The most important
result of this study was the discovery
and documentation of successful nest-
ing by C. acutus on the berms within the
cooling canal system at Turkey Point.
We located two nest sites in 1978, one
in 1979, and one in 1981. All nests were
found in the southwestern section of the
cooling canal system. For comparison,
the total number of nests located in Ev-
erglades National Park for the same
years was 11 in 1978, 14 in 1979, and 9
in 1981 (Mazzotti, 1983), and on north
Key Largo was 7 in 1978, 5 in 1979, and
4 in 1981 (Florida Game and Fresh Water
Fish Commission, 1979, 1980, 1982). A
total of 74 hatchlings were captured at
Turkey Point from 1978 through 1981,
which averages nearly 25 hatchlings per
year (excluding 1980, when no hatch
occurred). Mazzotti :'. : estimates that
212 hatchlings are produced in Ever-
glades National Park per year, while
Moler (pers. comm.) estimates that 40
hatchlings are produced annually on
north Key Largo. Thus, during years
when there is a hatch, Turkey Point
contributes approximately 10% of the C.
acutus hatchlings in southern Florida.
The man-made berms at Turkey Point,
which were created between 1969 and
1974, provide suitable nesting habitat
for C. acutus. The berms are elevated
above ambient groundwater levels
which prevents nest failure from flood-
ing. Pockets of peat suitable for nesting
(Ogden, 1978) are scattered throughout


FIG. 2. Salinities of canal systems at Turkey
Point during 1980. Horizontal bars = annual
means standardized by sample size; vertical bars =
range of seasonal means. C.S. = cooling canal sys-
tem; I.D. = Interceptor Ditch; M.L.C.E. = Model
Land Canal East; S.D.C. = Sea Dade Canal

the berms. The nesting berms have deep
water access, and are almost totally iso-
lated from human activity. Successful
nesting on the cooling canal system
berms indicates that C. acutus can utilize
nesting habitat created by human activ-
.:..'...'.;.:...: Structure.- Fig. 3 presents
data on the number of observation of C.
acutus (60 cm or larger) by size class,
location and season during the course
of the study period. We estimate that
17-19 individuals of all size classes oc-
cur at Turkey Point. A total of 1035 C.
acutus observations (including visual
and telemetry) were made during the
study. Approximately 27% of these
sightings were of juvenile or subadult
animals, compared to 68% in Everglades
National Park (Mazzotti, 1983). Mazzot-
ti (1983) suggests that juvenile and sub-
adult size classes are more difficult to
locate than hatchlings or adults. How-
ever, 68% of captured C. acutus at Tur-
key Point were subadults or juveniles,
compared to 58% in Everglades Nation-
al Park (Mazzotti, 1983).
Of the nine different juveniles cap-
tured, eight ^"'' were either first cap-
tured and marked as hatchlings, or at-
tributed to a known hatch on the basis


i. 4



0 J -m1 rrf-TT Li mrp P^




FIG. 3. Percent of total observations of C. acutus by size class and season in the canal systems at
Turkey Point. C.S. = cooling canal system; I.D. = Interceptor Ditch; M.L.C.E. = Model Land Canal East;
S.D.C. = Sea Dade Canal. ... :.i Size: Adult, N = 757; Subadults, N = 180; Juveniles, N = 98.)

of total length and weight. Approxi-
mately 11% of captured hatchling C.
acutus are known to have survived for
at least a year and grew to juvenile size.
All but one of these captured juveniles
were located on the study site at the
time of their last capture; the exception
was last observed in Barnes Sound 13.1
km from the study site, indicating that
Turkey Point crocodiles do not spend
their entire lives at the power plant site.
Three subadults (2 males, 1 female)
accounted for only 19% of the animals
captured. Mazzotti (1983) reports that
subadults are usually the least repre-
sented size class found in crocodilian
populations. Our capture data tend to
confirm this at Turkey Point. This may
be a result of rapid growth rate in the
size class, or their secretive habits. The

secretive behavior of subadults is dem-
onstrated by the fact that 35% of all sub-
adult observations for the study were a
result of telemetry fixes on two animals
during the breeding season (March
through August) of 1980.
Four adult crocodiles (1 male, 3 fe-
males) were captured at Turkey Point.
In addition, there were at least two oth-
er adult crocodiles at the study site that
we were unable to capture. Adult C.
acutus observations accounted for about
73% of the total sightings (Fig. 3), even
though adults comprised only 25% of
captured individuals.
Adult crocodiles .. . are less se-
cretive than the younger age classes. At
Turkey Point, their preferred basking
sites are along the Interceptor Ditch,
which is alongside a road. An observer


surveying from this road has a virtually
unobstructed view of the Interceptor
Ditch, which has a very small amount
of co;--- --!';- shoreline vegetation
compared to other canals at the site. In
S,. National Park, adults com-
prised 32% of the total sightings (Maz-
zotti, 1-''.. At Turkey Point, daytime
sightings of adult C. acutus represented
82% of all adult sightings, while 63% of
subadult sightings and only 28% of ju-
venile sightings occurred in the day-
Mazzotti's data (1983) indicate that the
minimum length at which female C.
acutus become sexually mature in south-
ern Florida is 2.25 m. The three adult
female crocodiles captured at Turkey
Point exceeded this minimum length,
and are breeding size. One female croc-
odile was observed with a pod of young
in a cooling canal adjacent to the nest
site in 1981.
The ratio of females to males (adults
and subadults) at Turkey Point is 1.3:1,
compared to 2.4:1 in Everglades Nation-
al Park (Mazzotti, 1983). The difference
in the two ratios may be a function of
the small sample size, or the Turkey
Point animals may represent a young
population that has not yet achieved
Habitat T. '.* ... -Crocodylus acutus
habitat at Turkey Point is completely
man-altered, and in several ways is very
different from the more natural habitat
of C. acutus that exists in F.. 1 : 1 Na-
tional Park and the intermediate habi-
tats present on north Key Largo. Unlike
Everglades National Park there are no
sand beaches at Turkey Point or on
north Key Largo. Although there are
vast areas of -.. ...... swamp, tidal
creeks and shallow ponds on and adja-
cent to Turkey :::f. only a very few
(less than 10 out of 1035) observations
occurred in these areas. In Everglades
National Park crocodiles spend most of
their time in red mangrove habitats
(Mazzotti, 1983).
-' ..': "s (1983) data show that in
Everglades National Park C. acutus pre-

fer sheltered areas rather than open
bays. He reported that over 75% of his
observations were in habitats character-
ized by relatively deep water, protec-
tion from wave action and onshore
winds, often with banks undercut or
overhung by mangrove roots. The ca-
nals at Turkey Point provide similar
protected habitat for C. acutus.
The canal systems at Turkey Point are
close to one another (Fig. 1), but are uti-
lized differentially by the various size
classes of C. acutus (Fig. 3). S.":..:: has
long been thought to be an important
factor in the biology of C. acutus (Dun-
son, 1970, 1980, 1982; Evans and Ellis,
1977; Ellis, 1981; Mazzotti, 1983). It was
hypothesized that salinity could be a
key factor in the determination of hab-
itat preferences of various size classes
at Turkey Point.
Mazzotti (1983) documents that in
F.- ::.. National Park adult C. acu-
tus prefer lower salinity habitats than
subadults, with juveniles occurring in
areas with the highest mean salinity
(20.1 ppt). Our data also indicate that C.
acutus habitat preference varies by size
class (Fig. 3). Approximately 83% of all
adult observations were made in the
freshwater Interceptor Ditch, whereas
only 13% of juvenile and subadult ob-
servations occurred there. Conversely,
while only 9% of adult observations
were in the brackish canals (i.e., C-107,
M.L.C.E., S.D.C.), more than of sub-
adult and juvenile observations oc-
curred in these canals.
Observations of adults in the hyper-
saline cooling canal system comprised
less than of total observations, while
of ; ....:. and subadult observa-
tions were there. Only one of the twelve
juvenile and subadult crocodiles cap-
tured at Turkey Point was in the Inter-
ceptor Ditch; all but one adult C. acutus
captures occurred there. The mean sa-
linity for juvenile captures at Turkey
Point was 25.2%o, which is comparable
to Mazzotti's (1983) findings.
However, the low frequency of sight-
ings of subadults and juveniles in the


freshwater Interceptor Ditch may result
from social interaction with adults, and
may not represent a salinity preference.
That C. acutus were never observed in
the freshwater canal L-31E (Figs. 1 and
2), suggests that C. acutus may avoid
otherwise suitable habitat which is ex-
ploited by American alligators :* .
Seasonal Distribution.-Mazzotti (1983)
demonstrates seasonal changes in the
distribution of C. acutus, correlating
these changes with the onset of the
breeding season. In Everglades Nation-
al Park, i .......i. prefer the inland
(freshwater) areas during the non-
breeding season and move to Florida
Bay (saline) during the breeding sea-
son. Mazzotti further suggests that the
movement to Florida Bay may also cor-
relate with the onset of the rainy season
which results in decreased salinities in
Florida Bay.
At Turkey Point there is a decrease in
the use of the freshwater Interceptor
Ditch by adult female crocodiles .' : : .
the breeding season, and a correspond-
ing increase in the use of the hypersa-
line cooling canal system. Observations
in the Interceptor Ditch decreased from
83% (non-breeding) to 70% (breeding),
while observations in the cooling canal
system increased from 2% (non-breed-
ing) to 9% (breeding).
Seasonal distribution of C. acutus at
Turkey Point is comparable to that re-
ported in Everglades National Park by
Mazzotti (1"- Adult female C. acutus
cross from the Interceptor Ditch to the
cooling canal system more frequently at
the start of the breeding season. In Ev-
erglades National Park, adult females
move to Florida Bay nesting areas at the
same time (Mazzotti, 1983). Mazzotti
speculates that females tolerate the
higher salinities in Florida Bay because
the sand beaches there provide the only
suitable nesting habitat. We have dem-
onstrated that adult females prefer fresh
water of the Interceptor Ditch, but they
nest in the hypersaline cooling canal
system, because the berms in the cool-

ing canal system provide the ...-1. !suit-
able nesting habitat in the area.
Recruitment and T.'; --Mazzotti
(1983) and Jacobsen (1983) have docu-
mented that individual C. acutus can
move long distances in relatively short
periods of time. The three centers of C.
acutus nesting activity (Everglades Na-
tional Park, north Key Largo and Tur-
key Point) are certainly close enough to
allow crocodiles from one area to inter-
act with crocodiles from the other areas.
We have never captured a crocodile
marked in Everglades National Park or
on north Key Largo at Turkey Point.
However, Paul Moler (pers. comm.)
captured a juvenile crocodile that
hatched in 1979 at Turkey Point and a
juvenile crocodile hatched in Ever-
glades National Park along the western
shoreline of Barnes Sound. Eighteen
months after its last capture the Turkey
Point hatchling was approximately 13.1
km from its last known location. These
observations prove that long distance
dispersal from nest sites occurs, and that
long distance movements are not lim-
ited to adult C. acutus.
Nine individuals from 1978, 1979, or
1981 hatches at Turkey Point are known
to have survived for at least a year after
the hatch. One individual from the 1978
hatch was observed in November 1982
in Model Land Canal East (Fig. 1); this
animal had reached subadult size.
Therefore, recruitment is occurring in
the population at Turkey Point.

Documentation of an American croc-
odile population at Turkey Point, which
is composed of all size classes and be-
haves ecologically similar to the larger
population in Everglades National Park,
has major implications for the overall
status of C. acutus in southern Florida
and throughout its range. The existence
of a third major C. acutus nesting area
in southern Florida which contributes
approximately 10% of the hatchlings to
the annual southern Florida totals is
important for this endangered species.


Furthermore, recruitment into older,
more survivable size classes from these
hatches has occurred at Turkey Point.
The discovery of juvenile crocodiles
from Turkey Point and Everglades Na-
tional Park in Barnes Sound suggests
that the ... .::... of genetic informa-
tion occurs among the three C. acutus
population centers in southern Florida.
The capture of nine juveniles and three
subadults indicates the potential for an
increasing number of sexually mature
crocodiles residing at Turkey Point. The
availability of suitable ... ':... habitat
will not be a limiting factor to the con-
tinued success and expansion of the
We have shown that crocodiles will
.. 1 1',. exploit man-made habitat if the
habitat is near areas of C. acutus activity,
and if it meets basic .... ... .:. habitat
requirements. Turkey Point represents
excellent habitat for crocodiles.

Acknowledgments.-This study was
supported by funding from Florida
Power & Light Company, with addi-
tional funding from the U.S. Fish and
W.. .::.:. Service. We were assisted in the
field by M. Ahearn, B. Bohnsack, S. Car-
ney, E. Frank, J. Gleman, B. Hieber, P.
Krauss, S. Langley, D. 'i.i:. C. Rep-
erger, G. Romero, P. Rooney, E. Smillie,
N. Urban and A. Wohl (present or for-
mer staff at Connell Associates, Inc.) and
by the Land Utilization personnel at
Turkey Point, especially M. D'Orazio
and R. Hicks. Special thanks are due J.
C. Ogden of the National Audubon So-
ciety for his invaluable guidance in field
techniques. We are grateful to C. R.
Stone for his dedication to the study and
his commitment to the survival of the
American crocodile at Turkey Point. We
also thank P. Moler and K. Hill of the
Florida Game and Fresh Water Fish
Commission, H. C ,:. i 1 1 and S. Fun-
derburk of the U.S. Fish and Wildlife
Service, and J. Kushlan of the National
Park Service for their cooperation and
friendship. Editorial review by S. Lang-
ley is gratefully acknowledged. A. Lew-

is assisted in the preparation of graph-
ics. We also thank E. ':i:. : formerly
of Connell Metcalf & Eddy, Inc., whose
efforts initiated this study.

BEARD, D.B. 1938. Everglades National Park
Project. U.S. Dept. of Interior, National Park
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Accepted: 12 June 1984

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