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Biological Characteristics
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Species |
Pelecanus occidentalis is a large bird, about 114-137 cm in length. Males tend to have a greater average mass (3.7 kg) than females (3.2 kg) (Dunning, 1993). In adults, the body is brown and the head is white, and in young both are brown. The most prominent feature of this bird is its large bill and throat pouch (Bull and Farrand, 1977). |
|
Status in Estuaries |
Brown pelicans are colonial breeders that typically nest in vegetation located on coastal islands or on sandy beaches and lagoons. Nests are usually found in trees or in low bushes, but can occasionally be found on the ground (Williams, 1980; Bull and Farrand, 1977). Typical clutch size is 3 eggs. Young are altricial (Ehrlich et al., 1988). The maximum age of brown pelican recorded from nature is 19 years (Clapp et al., 1982). |
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Abundance and Range |
Historically, the species was found nesting south of Virginia, yet since 1987 colonies have also been found in Maryland and Virginia (Bull and Farrand, 1977; Wilkinson, 1994). As of 1991, about 27 brown pelican colonies were found in Maryland, Virginia, North Carolina, South Carolina, Georgia, and Florida’s Atlantic coast. The total Atlantic coast population was estimated at 13,737 individuals in 1991 (Wilkinson, 1994). Recent census estimates populations of 93,000 individuals, with 31,340 on the Atlantic coast and 43,524 on the Gulf coast (NACWCP, 2001) |
|
Site Fidelity |
Moderate |
|
Ease of Census |
Simple. Its large size and unique features such as the throat pouch make this a relatively easy to species to census (Williams, 1980). |
|
Feeding Habits |
Piscivorous. This species primarily feeds in shallow estuarine waters, but may be seen up to 40 miles offshore (Clapp et al., 1982). Fish, the main prey of the pelican, is caught by diving, and menhaden is a particular preference. The pelican will occasionally feed on prawns (Palmer, 1976). |
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|
I. |
Organochlorine Contaminants |
|
A. |
Concentrations
in Adults, Juveniles, and Nestlings |
|
1. |
In
1969, apparently healthy brown pelicans from the Anacapa Islands were
analyzed for PCBs (Bischoff
et al., 1970). Average concentrations were found to be 144 µg/g in the
fat and 163 µg/g in the flesh. In addition to analyzing healthy birds,
brown pelicans found dead along the coast of California were also analyzed
for PCBs. Concentrations
averaged 60.4 µg/g in the brain and 179.0 µg/g in the flesh. |
|
2. |
In
1970, carcasses of brown pelicans from Florida and South Carolina were
examined for organochlorine contamination (Blus et al., 1974a). Adult and
immature birds had higher concentrations of organochlorines in their
tissues than newly hatched birds (1 to 13 weeks old). In general, low
levels of DDD, DDT,
mirex, and dieldrin
were detected in all birds sampled. DDE
was highest in an immature bird from Florida's Gulf Coast at 31.00 µg/g
wet weight. PCBs were highest
at 35.0 µg/g in an adult bird collected from South Carolina. One pelican
exhibited tremors immediately prior to death and had concentrations of
11.04 µg/g DDE and 20.0 µg/g
PCBs in the carcass. In the
brain of this bird, levels of DDE
were similar and levels of PCBs
were lower. All other organochlorines occurred at lower concentrations. |
|
3. |
Organochlorine
concentrations were measured in the brain, fat, liver, and muscle of adult
and nestling brown pelicans collected from Florida in 1971 and 1972
(Nesbitt et al., 1981). The highest levels of organochlorines were found
in the fat. DDE was 5.339 µg/g
wet weight in the fat of healthy birds sampled from the juvenile,
sub-adult and adult age groups and 13.193 µg/g for the nestlings. No
age-related differences in contaminant burden were detected between
healthy groups, though higher residue levels were found in
"sick" and dying birds. All values detected in the brown
pelicans were found to be less than those known to cause reproductive
failure. |
|
4. |
Pelicans
found dead from South Carolina, Georgia, the Atlantic coast of Florida and
from Florida Bay between 1971 and 1973 were analyzed for organochlorine
contaminants (Blus et al., 1977). The highest concentrations of DDE
and PCBs were found in birds
collected from Florida's Atlantic Coast. DDE
levels reached 10.00 µg/g wet weight and PCBs
reached 25.0 µg/g in the carcass of the same adult female. In South
Carolina, values of all organochlorines tested were <1 µg/g, with the
exception of PCBs, which were
4.0 µg/g in the carcass of a male collected in 1971. Concentrations of
organochlorines were generally higher in the single adult female collected
from Georgia, at levels of 5.50 µg/g DDE,
5.30 µg/g dieldrin and 10.0
µg/g PCBs. Low levels of
organochlorines were detected in all birds collected from Florida Bay. |
|
5. |
Organochlorine
residues were measured in adipose tissue and breast muscle of adult brown
pelicans collected in 1972, 1973 and 1975 from nesting locations on the
Gulf of California (Keith., 1978). DDE
was highest in the adipose tissue at 161 µg/g wet weight in 1973. DDD
was also highest in adipose tissue at 3.6 µg/g in 1972 and in 1973. DDT
(4.0 µg/g), endrin (1.1 µg/g),
dieldrin (2.1 µg/g) and PCBs
(53 µg/g) were all highest in 1973. |
|
6. |
Seven
brown pelicans found dead between 1974 and 1975 in South Carolina were
collected for organochlorine analysis (Blus et al., 1979b). Organochlorine
contaminant concentrations were higher in adults collected in 1975 than in
nestlings collected in 1974, though still lower than established lethal
levels. Highest individual levels detected were in adult males, at 3.43 µg/g
wet weight DDE in the brain,
and 1.25 µg/g TDE, 1.87 µg/g
dieldrin, and 38.80 µg/g PCBs
in the carcass. |
|
7. |
Nine
brown pelicans collected from the Gulf of California in 1980
and one pelican found dead from Anacapa Island
all contained <1 µg/g wet weight DDE
in the carcass homogenate, breast muscle, and wing muscle (Ohlendorf et
al., 1985). |
|
B. |
Concentration
in Eggs |
|
1. |
In
1969, 10 brown pelican eggs were collected from Anacapa Island, California
(Lamont et al., 1970). Residue levels in the eggs ranged from 39.5 µg/g
to 135.0 µg/g wet weight p,p’-DDE,
0.3-3.4 µg/g p,p’-DDD
and 0.6-3.8 µg/g
p,p’-DDT. Concentrations of o,p’-DDT
and o,p’-DDD
were 0.1 µg/g and concentrations of
dieldrin 0.2 µg/g. PCBs
were present in all samples. |
|
2. |
In
1969, eggs were collected from Los Coronados, San Martin Island, and San
Benito Islands located in northwest Baja California (Jehl, 1973). Mean DDE
(1310 µg/g lipid weight), DDT
(22.0 µg/g), DDD (37.6 µg/g),
PCBs (361 µg/g) and dieldrin
(20 µg/g) were highest from Los Coronados. Endrin
was not detected at Los Coronados and at San Benito Islands but averaged
1.7 µg/g from San Martin Island. In 1970 eggs were again collected from
Los Coronados and all contaminants analyzed (DDE,
DDT, DDD, and PCBs)
were lower than 1969 values. |
|
3. |
From
1969 to 1974, eggs were collected from South California, Northwestern Baja
California, and West-central Baja California (Anderson et al., 1975). In
1969, total DDT from southern
California and northwestern Baja California was 1204.3 µg/g lipid weight
in crushed eggs and 906.7 µg/g in intact eggs. A decline in total
DDT occurred steadily and by 1974 residues measured 96.6 µg/g,
all eggs intact. In West-central Baja California total
DDT in 1969 measured 96.1 µg/g, all eggs intact. |
|
4. |
From
1969 to 1970, eggs were collected from South Carolina, numerous locations
throughout Florida, and in California (Blus et al., 1974b).
Residues in South Carolina eggs were highest in Deveaux Bank,
reaching geometric means of 6.36 µg/g wet weight DDE,
1.81 µg/g DDD, and 6.99 µg/g
PCBs. Low concentrations of DDT
and dieldrin were detected at
all locations. Residues in eggs from various locations throughout Florida
were highest from an Atlantic coast colony at geometric means of 2.44 µg/g
DDE and 1.98 µg/g PCBs.
Low levels of DDD,
DDT, and dieldrin were detected at all locations. Residues in eggs
from Anacapa, California had geometric means of 71.35 µg/g DDE
was wet weight and 3.60 µg/g PCBs. All other organochlorines were detected at lower
concentrations. |
|
5. |
From
1969 to 1970, 172 eggs were collected from brown pelicans located in
Florida (Schreiber and Risebrough, 1972). Mean total
DDT was detected in all Florida locations at concentrations
ranging from 1.19 to 2.90 µg/g wet weight. PCBs
were highest in Saint Petersburg in 1969 at 6.21 µg/g and lowest in Key
Charlotte Harbor in 1970 at 2.20 µg/g. |
|
6. |
In
1970, eleven brown pelican eggs were collected from various locations in
Texas (King et al., 1978). Mean contaminant concentrations were 3.23 µg/g
wet weight DDT (sum of DDD,
DDE and DDT) and 9.73 µg/g PCB.
Dieldrin was not detected. |
|
7. |
Eggs
were collected in 1970 (N=11) and 1974 (N=5) from the Gulf Coast of Texas
(King and Flickinger, 1977). In 1970, mean (range) residues concentrations
were 3.2 (2.4-4.2) µg/g wet weight DDE
and 10 (3-20) µg/g PCB. In
1974, residues had dropped to 0.86 (0.29-1.40) µg/g DDE and 3.0 (1.30-4.70) µg/g PCB. In 1974 low levels of dieldrin, endrin and DDD
were also detected. |
|
8. |
In
1971, 40 "apparently viable" and 3 "apparently
non-viable" brown pelican eggs were collected, and in general the
more contaminated eggs were from the eastern coast of Florida (Thompson et
al., 1977a). Total DDT
was 1.318 µg/g wet weight along the eastern coast of Florida and 1.191 µg/g
along the western coast. Dieldrin
was detected at concentrations <1 µg/g along both coasts and PCBs
(1254) were significantly greater along the eastern coast at 2.241 µg/g
than the western coast at 1.038 µg/g . |
|
9. |
In
1971, 1972, and 1973, brown pelican eggs were collected from Marsh Island
and Deveaux Bank, South Carolina (Blus et al., 1977). In 1971, the
geometric mean for DDE was
2.48 µg/g wet weight at both locations and PCBs
were highest in eggs from Deveaux Bank at 6.48 µg/g. In 1972, a slight
increase in DDE and PCB
concentrations were seen. Geometric means were highest for both substances
at Deveaux Bank at 3.05 µg/g DDE
and 8.79 µg/g PCBs. This
slight increase reversed in 1973 when the geometric means dropped to 2.16
µg/g for DDE and to
4.62 µg/g for PCBs. All
other organochlorines were <1 µg/g in all three years. |
|
10. |
In
1971 and 1972, freshly laid eggs were collected from the Cape Romain
National Wildlife Refuge (Blus et al., 1974b). Geometric mean values for DDE
were significantly higher in eggs from unsuccessful nests, 3.43 µg/g wet
weight, than from successful nests, 1.77 µg/g. Dieldrin
and DDD were also
significantly higher in unsuccessful nests. PCBs
were suggested to be higher in unsuccessful nests, 7.94 µg/g, than in
successful nests, 5.50 µg/g, but the apparent difference was not
statistically significant. |
|
11. |
In
order to restore the Louisiana population of brown pelicans, 465 nestlings
were transplanted from Florida to Louisiana from 1968 to 1973 (Blus et
al., 1975). From 1971 to 1973, 36 eggs of brown pelicans in Louisiana were
collected for contaminant analysis. The geometric mean concentration of DDE
was greatest in 1972 at 1.36 µg/g wet weight. DDD,
DDT, dieldrin,
heptachlor epoxide,
cis-chlordane, cis-nonachlor,
and toxaphene were all
detected at <1 µg/g. PCBs
were highest in 1971 at 3.91 µg/g. Endrin,
which was hypothesized to be the cause of the previous population crash in
Louisiana, was not detected any of the eggs examined. It should be noted
however that in a later paper (Blus et al., 1979a) the authors stated
"we previously reported an absence of endrin
in brown pelican eggs collected in Louisiana from 1971 through 1973. Since
then, we reanalyzed those eggs and found endrin
in all of them." |
|
12. |
From
1971 to 1976, organochlorine contaminants were measured in brown pelican
eggs laid in Louisiana (Blus et al., 1979a). The geometric mean was
highest for DDE in 1972 at
1.36 µg/g wet weight and for dieldrin
in 1975 at 1.08 µg/g. DDD, DDT,
heptachlor epoxide, chlordanes,
toxaphene, and endrin were all detected at means <1 µg/g wet weight. PCBs
were detected at a high concentration of 3.91 µg/g. |
|
13. |
A
brown pelican egg collected in 1972 along the west coast of Florida
contained concentrations of 2.46 µg/g dry weight DDE,
1.30 µg/g PCB, and 0.10 µg/g
dieldrin (Lincer and Salkind,
1973). |
|
14. |
Eggs
were collected from two locations in South Carolina and along the coast of
Florida in 1974, and again from South Carolina in 1975 (Blus et al.,
1979b). For South Carolina in 1974, the average geometric mean
concentrations for DDE were
2.35 µg/g wet weight in eggs from Marsh Island and 1.96 µg/g from
Deveaux Bank. The geometric mean for PCBs
was highest at 8.32 µg/g from Marsh Island. In 1975, residue levels were
again highest at Marsh Island, with geometric means of 1.30 µg/g
DDE, and 7.23 µg/g PCBs.
In Florida, the geometric means of both residues were highest on the
Atlantic Coast at 1.32 µg/g DDE
at Port Orange and 7.79 µg/g PCBs
at Fort Pierce. All other organochlorines were detected at levels <1 µg/g
in both states for both years. |
|
15. |
From
1975 to 1981, 103 addled eggs were collected from coastal areas of Texas
(King et al., 1985). Variations in DDE
concentrations were observed during the sampling years, yet no significant
decrease was seen between 1975 and 1981. Specifically, geometric mean
concentrations ranged from 0.9 µg/g wet weight in 1979 up to 2.3 µg/g in
1977. Very low concentrations of DDD,
DDT, dieldrin and chlordane
were detected in all eggs sampled. A drop in PCB concentration occurred between 1975 (4.0 µg/g) and 1981
(1.1 µg/g) yet was not found to be significant. |
|
16. |
In
1977, eggs were collected from two South Carolina colonies: Deveaux Banks
and Cape Romain National Wildlife Refuge (Mendenhall et al., 1978).
Geometric means for DDE, DDD,
DDT, dieldrin,
cis-chlordane,
trans-nonachlor,
cis-nonachlor,
and toxaphene were <1 µg/g
wet weight. PCBs occurred at
a geometric mean concentration of 5.3 µg/g. When examining contaminant
trends in these colonies between 1969 and 1977 a significant decrease in DDE
and dieldrin occurred. No
significant drop in PCBs was
seen. The author noted that the eggs collected in 1977 represented the
first sampling in which all eggs had DDE
residues lower than 2.5 µg/g and dieldrin
below 0.54 µg/g, levels that have previously been associated with nest
failure in this species. |
|
17. |
From
1980-82 and 1992-93, brown pelican eggs (N=46) were collected from one
site in Puerto Rico (Montalva Bay), and three sites in the U.S. Virgin
Islands (Congo Cay, Ducthcap Cay, and Conejo Cay) (Collazo et al., 1998).
In eggs collected between 1980-82, concentrations of DDE
and PCB were significantly
higher at the Puerto Rico site (0.65 and 7.84 µg/g wet weight,
respectively), than the Virgin Islands sites (0.06 and 1.00 µg/g).
Contaminant concentrations were significantly lower in eggs
collected in 1992-93, and there were no significant geographic
differences. Concentrations
of DDE and PCB
were 0.01 and 0.13 µg/g at Puerto Rico, and 0.02 and 0.30 µg/g in the
Virgin Islands. |
|
18. |
Eggs
were taken from a dredge spoil island and a control site off the South
Carolina coast in 1994 (Wickliffe and Bickham, 1998).
The mean concentration of TCDD-EQ
was below detection at the control site and 4.5 pg/g wet weight at the
spoil site. |
|
II. |
Cholinesterase-Inhibiting Pesticides |
|
|
No
direct exposure data available |
|
III. |
Trace Elements, Metals, and Metalloids |
|
A. |
Concentrations
in Adults and Nestlings |
|
1. |
In
1970, hepatic metal concentrations were determined in four brown pelicans
found dead in Florida and South Carolina (Blus et al., 1977). Low
concentrations of Cr, Ni,
As, Cd,
Cu, Zn and Mg
were detected. Selenium
occurred at a high concentration of 4.42 µg/g wet weight, Hg
at 4.10 µg/g, and Pb was
detected at 0.10 µg/g in all four birds. |
|
2. |
Metal
concentrations in livers of nestling, immature and adult brown pelicans
were measured in birds found dead in South Carolina, Florida, and Georgia
in 1972 and 1973 (Blus et al., 1977). Chromium
and Ni concentrations were
<0.1 µg/g wet weight. Selenium
was highest (4.04 µg/g) in an immature male collected from Florida. Arsenic
had a maximum at 1.02 µg/g, Hg
at 6.30 µg/g and Pb at 0.27
µg/g. Low concentrations of Cd,
Cu, Zn,
and Mg were detected. Mercury
was also measured in the liver of birds shot in Florida and South Carolina
in 1970, and the maximum value was 4.10 µg/g in a bird from Florida. |
|
3. |
In
1980, nine brown pelicans (collected by shotgun) and one found dead from
the Gulf of California were analyzed for metals (Ohlendorf et al., 1985). Arsenic
occurred at similar concentrations in the liver and in the kidney at 0.32
and 0.21 µg/g dry weight. Copper
(23.5 µg/g) and Se (21.1 µg/g)
were highest in the liver and Cd (18.2
µg/g) and Cr (3.71 µg/g)
were highest in the kidney. Lead and
Zn were highest in the
humerus at arithmetic means of 7.44 and 108.1 µg/g, respectively. |
|
4. |
In
1996, liver and kidneys were collected from terminally ill (from type C
botulism) brown pelicans from Salton Sea National Wildlife Refuge (n=9),
and healthy brown pelicans at Sea World of California, San Diego (n=4) (Bruehler
and de Peyster, 1999). Elements
were detected in all samples unless noted.
Liver and kidney geometric mean concentrations and ranges of Se
were 16.9 (13.0 - 34.3) and 18.8 (13.8 – 27.2) µg/g dry weight from
Salton Sea, and 9.3 (4.4 - 13.1) and 13.9 (6.5 – 28.7) µg/g from Sea
World. Liver and kidney
concentrations of Zn were 148
(71 - 294) and 86 (30 – 156) µg/g from Salton Sea, and 238 (139 - 422)
and 86 (67 – 110) µg/g from Sea World.
Liver concentrations of Fe
were 2,513 (942 - 4,927) µg/g from the Salton Sea, and 7,342 (5,570 -
13,189) µg/g from Sea World. Liver
and kidney concentrations of Cd
were 0.58 (0.27 – 1.62) and 2.3 (0.96 – 7.22) µg/g for Salton Sea,
and 0.59 (0.4 – 1.5) and 3.6 (2.7 – 4.8) µg/g for Sea World.
Liver concentrations of Cr
were <0.0025 – 0.478 µg/g for Salton Sea (n = 1/9), and <0.0025
– 0.323 µg/g for Sea World (n = 2/4). Liver
concentrations for Pb were
<0.0125 µg/g for Salton Sea (n = 0/9), and <0.0125 µg/g for Sea
World (n = 0/4). Liver and
kidney concentrations of Cu
were 18.6 (8.5 – 34.4) and 9.2 (6.7 – 11.3) µg/g for Salton Sea, and
15.1 (9.1 – 38.8) and 7.2 (6.2 – 9.5) µg/g for Sea World. |
|
B. |
Concentrations
in Eggs |
|
1. |
In
1969, eggs collected from South Carolina, Florida, and California were
analyzed for metal content (Blus et al., 1974a). The geometric mean for Hg
reached a maximum of 0.83 µg/g wet weight at Matlacha located
on Florida's Gulf Coast. Lead
was detected at trace concentrations from all locations. The only
measurable concentration of Pb,
0.17 µg/g, occurred at Anacapa, California. In 1970, eggs collected from
South Carolina and Florida Bay had Hg concentrations
of 0.44 and 0.46 µg/g, respectively. Lead
was not reported in South Carolina samples, and was only detected in trace
quantities in samples from Florida. |
|
2. |
Brown
pelican eggs collected from Florida, between 1969 and 1970, and from South
Carolina, between 1971 and 1972, were analyzed for metals (Blus et al.,
1977). Arsenic occurred at
higher concentrations in South Carolina, 0.31 µg/g wet weight, than in
Florida, 0.10 µg/g. Little difference existed between sites for all
metals analyzed. |
|
3. |
In
1972, metals were measured in the eggs of brown pelicans transplanted to
Louisiana from Florida (Blus et al., 1975). Metals were detected at the
following geometric mean concentrations (µg/g wet weight):
0.004 Cd, 1.15 Cu,
5.9 Zn, 0.024 Ni, 0.08 Hg, and
0.016 Pb. The author notes
that based on their incomplete knowlege of the effects of metals on brown
pelicans, it is not believed that these concentrations pose a threat. |
|
4. |
From
1975 to 1978, metal analysis was completed on 33 brown pelican eggs
collected from the coast of Texas (King et al., 1985). Arsenic was at a maximum concentration in 1977 at 0.25 µg/g
wet weight, Hg in 1978 at
0.28 µg/g, and Se and
Zn in 1976 at 0.50 and 8.82 µg/g, respectively. The author
notes that these concentrations are lower than those known to adversely
affect hatchability and nestling survival in other bird species. |
|
5. |
From
1980-82 and 1992-93, brown pelican eggs (N=46) were collected from one
site in Puerto Rico (Montalva Bay), and three sites in the U.S. Virgin
Islands (Congo Cay, Ducthcap Cay, and Conejo Cay) (Collazo et al., 1998).
Concentrations of Hg
were significantly greater in eggs collected in 1980-82 (0.205 µg/g wet
weight) than in those collected in 1992-92 (0.0001 µg/g).
Concentrations of Hg
did not differ between sites. |
|
6. |
Eggs
were taken from a dredge spoil island and a control site off the South
Carolina coast in 1994 (Wickliffe and Bickham, 1998).
Mean concentrations of As, Se, and
Hg were 0.01, 0.34, and 0.26 µg/g wet weight, respectively,
at the spoil site and 0.03, 0.38, and 0.34 µg/g at the control site. |
|
IV. |
Petroleum |
|
1. |
Interactions
of brown pelicans with floating oil
were studied in an area of naturally-occurring oil seeps off Coal Oil
Point, Santa Barbara Channel, California (Varoujean, 1982). Juveniles were
found to make more contact with oil
seepage slicks than adults. Of pelicans resting and feeding in the
vicinity of the slicks, 40% made contact with the oil.
|
|
V. |
Other Contaminants |
|
1. |
Brown
pelican livers had the following concentrations (in ng/g) of perfluorooctane
sulfonate: 48, 106, 125, 134, and 159 from Miami, Florida;
<6, 6, 16, 32, and 36 from Calipatra, California; and 31, 71, 75, 91,
and 194 from Ft. Lauderdale, Florida (Minnesota Mining and Manufacturing
Company 2000). |
|
Brown
Pelican Contaminant Response Data |
|
|
I. |
Organochlorine Contaminants |
|
A. |
Eggshell
Thinning and Reproductive Success |
|
1. |
A
series of population declines and extirpations have occurred (Blus, 1970).
The subspecies Pelecanus occidentalis
carolinensis was extirpated in the Gulf of Mexico in the early
1960's. In South Carolina, breeding birds dropped from over 5000 pairs in
the early 1960's to 1250 pairs by 1969. In California, brown pelicans
experienced total reproductive failure in the late 1960's. |
|
2. |
Significant
decreases in shell thickness were measured in brown pelican eggs collected
from Florida (N=81) and from South Carolina (N=49) (Blus., 1970). When
compared to pre-1947 eggs, a 7.5 % decrease was seen in Florida eggs and a
16.9% decrease in South Carolina eggs. |
|
3. |
Eighty-seven
eggs collected from various locations in Florida from 1969 to 1970 showed
a 9% decrease in mean shell thickness when compared to pre-1943 eggs from
Florida (Schreiber and Risebrough, 1972). |
|
4. |
In
1969 and 1970, brown pelican eggs from Florida and South Carolina were
significantly thinner than the pre-1947 eggs (Blus et al., 1974a). |
|
5. |
From
1969 to 1971 productivity and eggshell thickness was measured in three
brown pelican colonies, Los Coronados, San Marin, and San Benito Island,
located in northwestern Baja California (Jehl, 1973). In 1969, no young
were produced from Los Coronados, 80-100 were produced from San Martin,
and 50-100 were produced from San Benito Island. In 1970, only 3-5 young
were produced from Los Coronados, none from San Martin and only 1 from San
Benito Island. In 1971, the number of young produced in all three colonies
rose to 30-40 from Los Coronados, 10 from San Martin, and 260 from San
Benito Island. Eggshell thickness values for all three colonies ranged
from 0.303 to 0.468 mm, compared a pre-1943 mean of 0.57 mm. |
|
6. |
After
major reproductive problems, an increase in brown pelican productivity on
the Pacific coast of southern California and in northwest Baja California
from 1969 to 1974 was found to occur with an increase in eggshell
thickness (Anderson et al., 1975). The number of young fledged rose from 4
in 1969 to 1185 in 1974. By 1980, this number had risen to 1865 (Anderson
and Gress, 1983). Though shell thickness had increased, measurements in
1974 were still significantly less than normal. |
|
7. |
From
1969 to 1976, shell thickness from 150 Tampa Bay, Florida eggs was
measured and compared to pre-1943 values (Schreiber, 1977). From 1969
through 1973 shells were found to be 5% to 12% thinner than historical
values. A steady increase in thickness occurred from 1974 (6% thinner)
until 1976 (2% thinner). |
|
8. |
From
1969 to 1977, significant declines in South Carolina organochlorine
residues (except PCBs) were
coupled with an increase in shell thickness, reproductive success, and
population levels (Blus, 1982). By 1980, the South Carolina breeding
population had increased to about 4800 breeding pairs. |
|
9. |
The
number of brown pelican nests observed from 1969 to 1978 in South Carolina
increased from 1266 to 3353 (Mendenhall et al., 1978). An increase in nest
success was also observed in that time period in that the number of
fledged young per nest rose from 0.78 to 1.35. Despite these improvements,
eggs measured from this colony in 1978 were still 6% thinner than pre-1947
eggs. |
|
10. |
To
determine average shell thickness, 14 pelican eggs were collected from
Texas in 1970 (King et al., 1978). There was a significant 11% decrease in
shell thickness between eggs collected in 1970 and the thickness of 43
eggs collected prior to 1947. |
|
11. |
Eggs
collected from Texas in 1970 (N=11) and 1974 (N=5) were 10% and 8% thinner
than historical values (King and Flickinger, 1977). |
|
12. |
Eggshell
thickness in coastal Texas from 1970 through 1981 was at a maximum in 1977
(4% thinner than historical values) and a minimum in 1978-79 (14% thinner)
(King et al., 1985). |
|
13. |
In
1971 and 1972, eggs collected from unsuccessful nests at the Cape Romain
National Wildlife Refuge had significantly higher levels of DDE, dieldrin,
and DDD than successful nests
(Blus et al., 1974b). PCBs
were also higher in unsuccessful nests though not significantly |
|
14. |
Eggshell
thickness of Louisiana brown pelicans was 7% lower than pre-1947 eggs in
1971 and 12% lower in 1972 and 1973 (Blus et al., 1975). |
|
15. |
A
total of 147 brown pelican eggs collected from Louisiana between 1971 and
1976 showed a decrease of 6.7 to 13.5% in shell thickness when compared to
pre-1947 eggs (Blus et al., 1979a). |
|
16. |
Data
from South Carolina, Louisiana, and Florida were analyzed to examine the
relationship between organochlorine levels and nest success (Blus, 1982).
Successful nests (those nests which had at least one downy young leave the
nest) tended to have lower organochlorine values (DDT, DDD, DDE,
dieldrin and PCBs)
than unsuccessful nests. |
|
17. |
From
1980-82 and 1992-93, brown pelican eggs (N=46) were collected from one
site in Puerto Rico (Montalva Bay), and three sites in the U.S. Virgin
Islands (Congo Cay, Ducthcap Cay, and Conejo Cay) (Collazo et al., 1998).
Overall eggshell thickness increased from 0.496 mm in 1980-82 to
0.526 mm in 1992-93. Both
values were within the 95% confidence intervals of pre-1947 eggs (0.510
mm). |
|
B. |
Biochemical
and Morphological Responses |
|
1. |
An
adult female pelican found in Georgia between 1971 and 1973 with
organochlorine levels of 5.50 µg/g DDE,
5.30 µg/g dieldrin and 10.0
µg/g PCBs, was suspected to
have died from myocardial necrosis and dieldrin
poisoning (Blus et al., 1977). |
|
2. |
The
distribution of DDT was
examined in birds that were fed versus those which were starved (Thompson
et al., 1977b). After 1 week, a significant increase in the concentration
of DDE was seen in the fat of
starved birds as compared to those that were fed. After 2 weeks a
significant increase of DDE
was also seen in the brain of starved birds, and continued to occur in the
fat. |
|
3. |
In
1974, 300 of the 465 brown pelicans transplanted from Florida to Louisiana
were believed to have died from exposure to endrin
and other chlorinated hydrocarbons (Winn, 1975). |
|
4. |
Blood
samples were taken from pelicans reared at a dredge spoil island and a
control site off the South Carolina coast in 1994 (Wickliffe and Bickham,
1998). Mean “half-peak
coefficient of variation” (HPCV) in erythrocyte DNA content, high values
of which indicate genetic damage, was approximately 4.0 at the control
site and 3.1 at the spoil site. No
correlation was observed between HPCV of DNA content and TCDD-EQ. |
|
5. |
Excreta
were collected from 3 species of seabirds at 3 sites in Chile (Casini et
al., 2001). Elevated levels of porphyrins
occurred near Talcahuano, Chile. Excreta samples were collected from 3
brown pelicans. Porphyrin
levels in nmols/g estimated from graph were 1.00 copro-,
0.25 uro-, 2.75 proto-,
and 4.00 total porphyrins. |
|
II. |
Cholinesterase-Inhibiting Pesticides |
|
|
No
response data available |
|
III. |
Trace Elements, Metals and Metalloids |
|
1. |
Blood
samples were taken from pelicans reared at a dredge spoil island and a
control site off the South Carolina coast in 1994 (Wickliffe and Bickham,
1998). Mean “half-peak
coefficient of variation” (HPCV) in erythrocyte DNA content, high values
of which indicate genetic damage, was approximately 4.0 at the control
site and 3.1 at the spoil site. No
correlation was observed between HPCV of DNA content and As,
Se, or Hg. |
|
2. |
In
1996, liver and kidneys from 9 brown and 10 white pelicans terminally ill
from type C botulism were collected from Salton Sea National Wildlife
Refuge (n=19). Reference
samples were collected from healthy brown pelicans at Sea World of
California, San Diego (n=4) (Bruehler and de Peyster 1999).
Eleven of nineteen birds from Salton Sea had Se levels above 16
μg/g dry weight, the level known to cause immune suppression in other
birds. The authors suggest
the elevated levels of Se may have been a contributing factor in the
botulism infection. |
|
IV. |
Petroleum |
|
1. |
A
heavily oiled brown pelican
was found in November 1976 and died within 24 hours (King et al., 1979).
This was an incidence of a bird dying weeks after a known oil spill. |
|
2. |
In
1982, after a diesel oil
spill of approximately 80,000 gallons in the Cape Fear River of North
Carolina, the repercussion of this spill on brown pelicans was measured
(Parnell et al., 1984). In all, of 98 nests studied, 24 were found to have
at least some oil
contamination. Of these 24, 15 were 'lightly oiled', 7 'moderately oiled'
and only 1 'heavily oiled.' Hatching success in oiled
eggs was significantly less than in unoiled eggs. |
|
3. |
Brown
pelicans rehabilitated and released after exposure to oil
spills in the Southern California Bight in 1990 did not return to normal
breeding and survival conditions in 1991 (Anderson et al., 1996). Compared
to controls, rehabilitated birds disappeared at a higher rate, had a lower
survival rate, and showed no breeding activity, including even presence or
association with breeding colonies. |
|
|
|
|
Anderson,
D.W., J.R. Jehl, Jr., R.W. Risebrough, L.A. Woods Jr., L.R. Deweese, and
W.G. Edgecomb. 1975. Brown pelicans: Improved reproduction off the
southern California coast. Science 190:806-808 |
|
|
Anderson,
D.W., F. Gress, and D.M. Fry. 1996. Survival and dispersal of oiled brown
pelicans after rehabilitation and release. Marine Pollut. Bull.
32:711-718. |
|
|
Anderson,
D.W. and F. Gress. 1983. Status of a northern population of California
brown pelicans. Condor 85:79-88. |
|
|
Bischoff
A.I., Azevedo, J.A., and L.A. Woods. 1970. Pesticides investigations:
Current fish and wildlife problems. Cal. Dept. of Fish and Game. 3pp. |
|
|
Blus,
L. 1970. Measurements of brown pelican eggshell from Florida and South
Carolina. Bioscience 20:867-869. |
|
|
Blus,
L.J. 1982. Further interpretation of the relation of organochlorine
residues in brown pelican eggs to reproductive success. Environ. Pollut.
(Series A): 28:15-33. |
|
|
Blus,
L.J., A.A. Belisle, and R.M. Prouty. 1974a. Relations of the brown pelican
to certain environmental pollutants. Pestic. Monit. J. 7:181-194. |
|
|
Blus,
L.J., Burkett S. Neely, Jr., A.A. Belisle., and R.M. Prouty. 1974b.
Organochlorine residues in brown pelican eggs: Relation to reproductive
success. Environ. Pollut. 7:81-91. |
|
|
Blus,
L.J., A.A. Belisle, and R.M. Prouty. 1975. The brown pelican and certain
environmental pollutants in Louisiana. Bull. Environ. Contam. Toxicol.
13:646-655. |
|
|
Blus,
L.J., B.S. Neely Jr., T.G. Lamont, and B. Mulhern. 1977. Residues of
organochlorines and heavy metals in tissues and eggs of brown pelicans,
1969-73. Pestic. Monit. J. 11:40-53. |
|
|
Blus,
L., E. Cromartie, L. McNease, and T. Joanen. 1979a. Brown pelican:
Population status, reproductive success, and organochlorine residues in
Louisiana, 1971-1976. Bull. Environ. Contam. Toxicol. 22:128-135. |
|
|
Blus,
L. J., T. G. Lamont., and B S. Neely, Jr. 1979b. Effects of organochlorine
residues on eggshell thickness, reproduction, and population status of
brown pelicans (Pelecanus occidentalis)
in South Carolina and Florida, 1969-76. Pestic. Monit. J. 12:172-184. |
|
|
Bruehler,
G., and A. de Peyster. 1999.
Selenium and other trace metals in pelicans dying at the Salton
Sea. Bull. Environ. Contam.
Toxicol. 63:590-597.
|
|
|
Bull,
J. and J. Farrand, Jr. 1977. The
Audubon Society Field Guide to North American Birds. Alfred A.
Knopf, New York. 784 pp. |
|
|
Casini
S., M.C. Fossi, J.F. Gavilan, R. Barra, O. Parra, C. Leonzio, and S.
Focardi. 2001. Porphyrin levels in excreta of sea birds of the Chilean
coasts as nondestructive biomarker of exposure to environmental
pollutants. Arch. Environ. Contam. Toxicol. 41:65-72. |
|
|
Clapp,
R.B., R.C. Banks, D. Morgan-Jacobs, and W.A. Hoffman. 1982. Marine birds
of the southeastern United States and Gulf of Mexico. Part I: Gaviiformes
through Pelecaniformes. U.S. Fish and Wildlife Service, Office of
Biological Services, Washington, D.C. FWS/OBS-82/01. 637 pp. |
|
|
Collazo,
J.A., T. Agardy, E.E. Klaas,
J.E. Saliva, and J. Pierce. 1998.
An interdecadal comparison of population parameters of brown
pelicans in Puerto Rico and the U.S. Virgin Islands.
Colon. Waterbirds 21:61-65. |
|
|
Dunning,
Jr., J.B., ed. 1993. CRC Handbook of
Avian Body Masses. CRC Press, Ann Arbor. 371 pp. |
|
|
Ehrlich,
P.R., D.S. Dobkin, and D. Wheye. 1988. The
Birder’s Handbook. Simon & Schuster, New York. 785 pp. |
|
|
Jehl
Jr., J.R. 1973. Studies of a declining population of brown pelicans in
northwestern Baja California. Condor 75:69-79. |
|
|
Keith,
J.O. 1978. Synergistic effects of DDE and food stress on reproduction in
brown pelicans and ringdoves. Ph.D. dissertation, Ohio State University. |
|
|
King,
K.A., and Edward L. Flickinger. 1977. The decline of brown pelicans on the
Louisiana and Texas Gulf coast. Southwest Naturalist 21:417-431. |
|
|
King,
K.A., E.L. Flickinger., and H.H. Hildebrand. 1978. Shell thinning and
pesticide residues in Texas aquatic bird eggs, 1970. Pestic. Monitor. J.
12:16-21. |
|
|
King,
K.A., S. Macko, P.L. Parker, and E. Payne. 1979. Resuspension of oil:
Probable cause of brown pelican fatality. Bull. Environ. Contam. Toxicol.
23:800-805. |
|
|
King,
K.A., D.R. Blankinship, E. Payne, A.J. Krynitsky, and G.L. Hensler. 1985.
Brown pelican populations and pollutants in Texas 1975-1981. Wilson Bull.
97:201-214. |
|
|
Lamont,
T.G., G.E. Bagley., and W.L. Reichel. 1970. Residues of o,p’-DDD
and o,p’-DDT in brown pelican eggs and mallard ducks. Bull.
Environ. Contam. Toxicol. 5:231-236. |
|
|
Lincer,
J.L. and D. Salkind. 1973. A preliminary note on organochlorine residues
in the eggs of fish-eating birds of the west coast of Florida. Florida
Field-Nat. 1:19-22. |
|
|
Mendenhall,
V.M., R.M. Prouty. 1978. Recovery of breeding success in a population of
brown pelicans. Proc. Colon. Waterbird Group pp. 65-70. |
|
|
Minnesota
Mining and Manufacturing Company (3M). 2000. Sulfonated perfluorochemicals
in the environment: sources, dispersion, fate and effects. Unpublished
Report. March 1, 2000. 51 pp. |
|
|
NACWCP.
2001. Review Draft
II—North American Waterbird Conservation Plan. Volume One: Seabirds and
Colonial Waterbirds, 23 October 2001, Waterbird Conservation Steering
Committee, Washington DC (www.nacwcp.org/). |
|
|
Nesbitt,
S.A., R.E. Cowan, P.W. Rankin, N.P. Thompson, and L.E. Williams Jr. 1981.
Chlorinated hydrocarbon residues in Florida brown pelicans. Colon.
Waterbirds 4:77-84. |
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|
Ohlendorf,
H.M., D.W. Anderson, D.E. Boellstorff, and B.M. Mulhern. 1985. Tissue
distribution of trace elements and DDE in brown pelicans. Bull. Environ.
Contam. Toxicol. 35:183-192. |
|
|
Palmer,
R.S., ed. 1976. Handbook of North
American Birds. Vol. I. Yale University Press, New Haven. 567
pp. |
|
|
Parnell
J.F., M.A. Shields, and D. Frierson Jr. 1984. Hatching success of brown
pelican eggs after contamination with oil. Colon. Waterbirds 7:22-24. |
|
|
Schreiber,
R.W. 1977. Shell thickness in brown pelican eggs from Tampa Bay, Florida.
Florida Field Nat. 5:31-34. |
|
|
Schreiber,
R.W. and R.W. Risebrough. 1972. Studies of the brown pelican. I. Status of
the brown pelican populations in the United States. Wilson Bull.
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Thompson,
N.P., P.W. Rankin, P.E. Cowan, L.E. Williams, Jr., and S.A. Nesbitt.
1977a. Chlorinated hydrocarbon residues in the diet and eggs of the
Florida brown pelican. Bull. Environ. Contam. Toxicol. 18:331-339. |
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|
Thompson,
N.P., C.H. Courtney, D.J. Forrester, and F.H. White. 1977b.
Starvation-pesticide interactions in juvenile brown pelicans. Bull.
Environ. Contam. Toxicol. 17:485-490. |
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Varoujean,
D.H. 1982. Seabird-oil spill behavior study. Pac. Seabird Group Bull.
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J.K. and J.W. Bickham. 1998.
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Williams,
L.E., Jr., ed. 1980. Recovery plan for the Eastern brown pelican. Eastern
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P.M., S.A. Nesbitt, and J.F. Parnell. 1994. Recent history and status of
the Eastern brown pelican. Wildl. Soc. Bull. 22:420-430. |
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B. 1977. Pesticides decimate transplanted pelicans. Audubon 77:127-129. |
|