Species

Dendrocygna bicolor is 13-21 inches in length, with a wingspan of 36 inches, and adult males have a mass of approximately 670 grams (Sibley, 2000).  They are goose-like in appearance, have long legs, a tawny underside, a dark back, and a pale side stripe (Peterson, 1980; Kaufman, 1996)

Status in Estuaries

This species is most commonly found in fresh and brackish coastal marshes, as well as agricultural fields (Peterson, 1980; Ehrlich et al., 1988; Kaufman, 1996).  They build a nest of woven grasses on the ground next to water or several feet up in the vegetation of a marsh.  Clutch size ranges from 6-16 white eggs, though nests with many more eggs are found due to egg dumping (Kaufman, 1996).  Young are precocial, can swim and dive well, and obtain their own food, but parents are present (Kaufman, 1996).  The maximum age of a fulvous whistling-duck recorded in nature is 6 years and 6 months.

Abundance and Range

Found in tropical wetlands in Africa, Asia, North America, and South America.  Within the U.S., fulvous whistling-ducks live on the Gulf coast of Texas and Louisiana, Southern California, and have recently expanded their range to include Hawaii and the Atlantic coast of Florida.  They are common vagrants north of their range (Kaufman, 1996).  Range expansion is attributed to development of new rice production areas 
( Turnbull et al., 1989 ). Population size is declining in the southwest and increasing in the southeast (Kaufman, 1996). 

Site Fidelity

Wanders over broad areas in flocks; Gulf coast population migrates to Mexico in the winter (Kaufman, 1996).

Ease of Census

Difficult; fulvous whistling-ducks wander in flocks.

Feeding Habits

Primarily seed and grain consumers, but also ingest a small amount of insects, snails, and invertebrates. Forage often occurs at night in shallow water, and on land, including agricultural fields, prairies, and pastures (Kaufman, 1996; Ehrlich et al., 1988). 

Fulvous Whistling-duck Contaminant Exposure Data

      I.

Organochlorine Contaminants

1.

Birds found dead (N=35) in rice fields and adjacent pastures in Wharton, Brazoria, and Chambers counties, Texas, were collected between 1967 and 1971; eggs were collected from abandoned nests (Flicklinger and King, 1972).  Mean dieldrin was 0.6 μg/g in brain, 16 μg/g in whole body, and 13 μg/g in an unlaid egg.  One kidney sample contained 8 μg/g Hg.  Concentrations of aldrin were <0.1μg/g in all specimens.   

In Wharton county, young ducks contained 0.6 to 2.2 μg/g Hg in whole body and whole body composite samples; dieldrin ranged from 1.0-4.0 μg/g, endrin from 0.1-0.2 μg/g, and DDT and metabolites from 0.1-0.2 μg/g.  An adult male composite of brain, heart, kidney, and liver contained dieldrin, endrin and DDT and metabolites in the following concentrations (μg/g) 8.0, 0.3, 0.3; the brain alone contained 0.4, ND, and 0.4.  An adult female contained dieldrin, endrin, and DDT and metabolites in the following concentrations (μg/g): 0.4, ND, <0.1 in brain; 3.1, 0.1, 0.3 in whole body; and 13.0, <0.1, 4.3 in the unlaid egg.  In eggs from deserted nests that were sprayed with toxaphene in June, the range of concentrations (μg/g) were as follows: <0.1-3.4 dieldrin, ND-1.4 DDT and metabolites, ND-24.0 toxaphene, and ND-0.1 endrin.  In eggs collected from fields not sprayed with toxaphene the range of concentrations (μg/g) were as follows: 0.3-9.5 dieldrin, 0.1-0.7 DDT and metabolites, ND toxaphene, and 0.2-0.3 endrin.  

In Brazoria County, in 1 bird of unknown sex, the whole body contained 10 μg/g Ceresan material, and 17 μg/g dieldrin; endrin and DDT and metabolites were not detected.  A female contained the following concentrations (μg/g) of dieldrin: brain <0.1, whole body 0.5, unlaid egg 1.3; endrin and DDT and metabolites were not detected.  Mercury was 0.8 μg/g in brain and 0.2 μg/g in kidney.   

In Chambers county, 1 male contained dieldrin at 1.6 μg/g in brain and 2.0 μg/g in whole body.  Mercury was found in whole body at 6.0 μg/g and in kidney at 8.0 μg/g.  Another male contained 16.0 μg/g dieldrin, and 2.5 μg/g DDT and metabolites.  Endrin was not detected in either duck.   

In 1969, ducks from the zoo in San Antonio, Chambers county, Texas, were penned on fields seeded with rice treated with aldrin and Ceresan near Anahuac refuge (N=10) and on fields planted with untreated seeds in Anahuac refuge (N=10).  Mean (range) concentrations of dieldrin of birds (N=8) penned on fields planted with treated seeds were 2.3 (0.3-6.8) μg/g in brains, and 2.3 (<0.1-6.0) μg/g in whole body.  Mean (range) concentrations of dieldrin of birds (N=4) penned on fields planted with untreated seeds were 0.1 ( ND-0.4) μg/g in brain and <0.1 (ND-<0.1) μg/g in whole body.   

Nine (3 male, 6 female) ducks were force-fed aldrin and Ceresan-treated rice seed in the laboratory.  At the 5 mg/kg dose, aldrin (μg/g) ranged from ND-<0.1 in brain, and ND-4.8 in whole body; dieldrin from <0.1-0.4 in brain and 0.8-9.0 in whole body; endrin from ND-<0.1 in brain and ND-<0.1 in whole body; and Hg from 0.50-3.26 in kidney.  At 10 mg/kg, aldrin (μg/g) ranged from ND-<0.1 in brain and ND-4.6 in whole body; dieldrin from <0.1-8.4 in brain and from 3.3-23.6 in whole body; endrin from ND-<0.1 in brain and from 0.1-0.2 in whole body; and Hg from 1.15-1.70 in kidney.  At 20 mg/kg, aldrin (μg/g) was ND in brain and <0.1 in whole body; dieldrin was 6.8 in brain and 37.6 in whole body; endrin was <0.1 in brain and 0.3 in whole body; and Hg was 3.33 in kidney. 

2.

Adult ducks (N=15) were collected in April and May and juveniles (N=16) in July of 1983 in southern Wharton county, Texas (Flicklinger et al., 1986).  Mean (range) dieldrin residues in adults with rice in the gastrointestinal tract (N=7) were 0.65 (ND-1.9 μg/g).  In adults without rice (N=8), 2 contained dieldrin, at 2.0 and 4.3 μg/g.  There were no differences between males and females.  Endrin was detected in 4 adults, and ranged from ND-0.18 μg/g.  Juveniles had no detectable endrin or dieldrin concentrations.

3.

Adult ducks (N=19) were collected from the Caliacan, Sinaloa area of Mexico in May and July of 1981 (Mora et al., 1987).  Mean (range) concentrations were as follows (ng/g, dry weight):  DDE (N=4) 306 (37-2537); DDT (N=1) 60; HCB (N=4) 31 (6-145), BHC (N=4) 85 (55-132); heptachlor epoxide (N=4) 26 (1-510); dieldrin (N=2) 22; endrin (N=2) 27. 

4.

Adult and juvenile ducks were collected in 1984-5 from the Everglades Agricultural Area, Florida (Turnbull et al., 1989).   

Maximum concentrations (ng/g, wet weight) of pesticides in juvenile liver tissue (N=9) were as follows: aldrin 177.2 (mean=2.1, N=5); dieldrin 15.5 (mean=4.4, N=8); heptachlor 3.5 (mean=0.8, N=7); heptachlor epoxide 7.6 (mean=1.5, N=8); DDE 5.3 (N=1); diazinon 10.1 (N=2); trans-nonachlor 12.1 (N=2); oxychlordane 6.2 (N=2); mirex 11.8 (N=3); lindane 2.6 (N=2); ethyl parathion 0.4 (N=1); HCB 1.8 (N=2); chlorpyrifos 14.7 (N=1).   

Maximum concentrations of pesticides in adult liver tissue (N=21) were as follows: aldrin 180.7 (mean=9.4, N=19); dieldrin 70.5 (mean=5.4, N=20); heptachlor 2.5 (N=7); heptachlor epoxide 35.0 (mean=2.3, N=18); DDE 32.1 (mean=1.9, N=13); diazinon 161.1 (N=9); trans-nonachlor 19.4 (N=8); oxychlordane 5.7 (N=5); mirex 7.7 (N=4); lindane 3.2 (N=4); ethyl parathion 33.7 (N=4); HCB 1.6 (N=2); chlorpyrifos 3.9 (N=2).   

Maximum concentrations of pesticides in adult breast tissue (N=15) were as follows: aldrin 3.7 (N=4); dieldrin 22.8 (mean=0.7, N=12); heptachlor epoxide 6.7 (mean=0.1, N=10); DDE 112.4 (mean=2.6, N=13); trans-nonachlor 9.5 (N=5); oxychlordane 5.1 (N=2); ethyl parathion 2.2 (N=3); chlorpyrifos 9.7 (N=2). 

II.

Cholinesterase-Inhibiting Pesticides

No direct exposure data available

III.

Trace Elements, Metals, and Metalloids

No concentration data available

IV.

Petroleum

No residue data available

Fulvous Whistling-duck Contaminant Response Data

I.

Organochlorine Contaminants

1.

In 1969 ducks from the zoo in San Antonio, Chambers county, TX were penned on fields seeded with rice treated with aldrin and Ceresan near Anahuac refuge (N=10) and on fields planted with untreated seeds in Anahuac refuge (N=10) (Flicklinger and King, 1972).  Mean weight of birds on the fields planted with treated seeds decreased 25-240 g (mean 104) after 3 days in the pens, while birds penned on the fields planted with untreated seeds had about the same average weight on the third day as they did on the first.  Birds penned with the treated seeds showed listlessness, weakness, stumbling, and they were markedly underweight and in poorer physical condition than the other birds.  Test birds with >2.5 μg/g dieldrin in their brain died, those with <2.1 μg/g survived.  Dieldrin was <0.4 μg/g in brains of controls and up to 6.8 μg/g in treated birds.   

Nine (3 male, 6 female) ducks were force-fed aldrin and Ceresan-treated rice seed in the laboratory.  One bird on the 5 mg/kg dose died on day 1, and 4 were sacrificed; 3 birds on the 10 mg/kg dose died on days 1, 1, and 10, and 1 was sacrificed; the 1 bird on the 20 mg/kg dose died on day 4.   

II.

Cholinesterase-Inhibiting Pesticides

No response data available

III.

Trace Elements, Metals, and Metalloids

No response data available

IV.

Petroleum

No response data available 

References for Fulvous Whistling-duck

Ehrlich, P.R., D.S. Dobkin, and D. Wheye. 1988.  The Birder's Handbook.  Simon & Schuster, New York. 785 pp.

Flicklinger, E.L., and K.A. King.  1972.  Some effects of aldrin-treated rice on gulf coast wildlife.  J. Wildl. Manage. 36:706-727.

Flicklinger, E.L., C.A. Mitchell, and A.J. Krynitsky.  1986.  Dieldrin and endrin residues in fulvous whistling-ducks in Texas in 1983.  J. Field Ornithol. 57:85-90. 

Kaufman, K.  1996.  Lives of North American Birds.  Houghton Mifflin Company, New York. 675 pp.

Mora, M.A., D.W. Anderson, and M.E. Mount.  1987.  Seasonal variation of body condition and organochlorines in wild ducks from California and Mexico.  J. Wildl. Manage. 51:132-141

Sibley, D. A.  2000.  The Sibley Guide to Birds.  Alfred A. Knopf, New York. 545 pp.

Turnbull, R. E., F.A. Johnson, M.D.L.A. Hernandez, W.B. Wheeler, and J.P. Toth.  1989.  Pesticide residues in fulvous whistling-ducks from south Florida USA..  J. Wildl. Manage. 53:1052-1057.