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BIOLOGICAL AND ECOTOXICOLOGICAL CHARACTERISTICS OF TERRESTRIAL VERTEBRATE SPECIES RESIDING IN ESTUARIES

Redhead
Photo of pair of Redheads by Fred Fallon

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Redhead
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Biological Characteristics

Species

Aythya americana is 19 inches in length, with a wingspan of 29 inches and an adult mass of approximately 1,050 grams (Sibley, 2000). Males are generally heavier than females. The male has a gray body, with a brick-red head, yellow eyes, and a black breast, and the female is brown.  Both sexes have a gray wing stripe and a pale blue bill with a black tip. Immatures are similar to adult female (Niering 1998; Peterson 1980; Kaufman 1996)

Status in Estuaries

This species nests in marshes and prairie potholes, and is often found in estuaries, coastal areas, lakes, and bays in the non-breeding season (Niering 1998; Kaufman 1996; Erlich et al., 1988). A nest is built of dead vegetation lined with down and attached to live plants in a dense marsh (Kaufman 1996).  Clutch size ranges from 9-14 white or pale olive-buff eggs, though nests with many more eggs are found due to egg dumping (Kaufman, 1996).  Young are precocial (Erlich et al., 1988).  The maximum age of a redhead recorded in nature is 22 years and 7 months.

Abundance and Range

Redheads breed in western North America, from British Columbia, Mackenzie, and Manitoba to New Mexico, and winter in the southern U.S., Great Lakes, coastal New England, northern Mexico, and south to Guatemala, Cuba, Jamaica, and the Bahamas (Niering 1998; Erlich et al., 1988). One of the least common North American ducks (Niering, 1998), loss of habitat is probably primarily responsible for their decline (Kaufman, 1996).  The estimated population of redheads is approximately 1 million, and the population has appeared to be increasing over the past 10 years (Kelley et al., 1998).

Site Fidelity

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

Ease of Census

Simple. Concentrated in flocks in the winter (10,000’s), nest in close proximity.

Feeding Habits

Primarily nocturnal feeders that forage by diving or dabbling (Niering 1998; Erlich et al., 1988), the diet consists of 90% percent vegetation and 10% animal life (Hebert et al., 1990).  Redheads typically eat leaves, stems, seeds, and roots of aquatic plants, and occasionally aquatic insects, mollusks, and small fish (Kaufman 1996). 


Redhead Contaminant Exposure Data

I.

Organochlorine Contaminants

1.

At the Walpole Island delta, Ontario, in 1986, 16 resident and 2 migratory redheads were shot by hunters in July and August (Hebert et al., 1990).  HCB, OCS, and pentachlorobenzene (QCB) were quantified in the liver and muscle.  Mean hepatic concentrations for QCB, HCB, and OCS were 1.18, 20.01, and 85.60 ng/g for resident ducks and 0.49, 2.04, and 18.93 ng/g for migratory ducks.  Mean muscle concentrations for QCB, HCB, and OCS were 0.77, 10.76, and 4.78 ng/g for residents and 0.82, 1.66, and 3.49 ng/g for migratory ducks.  Concentrations were significantly greater in resident birds than in the migratory birds, and did not differ between mothers and their 3 month old chicks. 

2.

Redheads were collected from Port Mansfield, Texas; Port Aransas, Texas; and Chandeleur Sound, Louisiana in November-December 1987, and February-March 1988 (Michot et al., 1994).  Mean concentration of DDE (ug/g wet weight) for Port Mansfield, Port Aransas, and Chandeleur Sound were 0.17, 1.86, 0.14 in early season adults, 0.66, 0.30, 0.10 in late season adults, 0.58, 0.09, 0.11 in early season immatures, and 1.23, 0.23, 0.26 in late season immatures.  In Port Mansfield, late season adults contained significantly more DDE than those from Chandeleur Sound; late season immatures contained more DDE than those from the other sites.  In Port Aransas, early season adults contained more DDE than those from Chandeleur Sound. 

3.

Redheads (N=3) collected from the Detroit River near Fighting Island were 33% male, 67% adult, mean mass was 1085g, mean length was 50cm, diet was primarily macrophytes, and mean contaminant concentrations (ng/g lipid weight) were as follows: HCB 5, PCB 28 3, PCB 149 9, PCB 153 16, PCB 180 7, PCB 194 1, total PCBs 179 (Mazak et al., 1997).

II.

Cholinesterase-Inhibiting Pesticides

 

No direct exposure data available

III.

Trace Elements, Metals, and Metalloids

1.

Of 456 redheads collected by hunters in the late fall and early winter of 1937-1950, 13.60% contained Pb shot in their gizzard (Bellrose 1951).  Of these, 8.34% contained 1 shot, 1.76% contained 2, 1.31% contained 3, 0.44% contained 4, and 1.75 contained more than 6.  Of the 12 species studied, the redhead had the greatest occurance of shot.

2.

Redheads were collected from Port Mansfield, Texas; Port Aransas, Texas; and Chandeleur Sound, Louisiana in November-December 1987, and February-March 1988 (Michot et al., 1994).  Mean (range) for elements in liver (N=70) are as follows (ug/g dry weight): As 0.59 (<0.30-2.70), B 4.74 (<3.00-12.80), Cd 0.91 (<0.80-5.41), Hg 0.06 (<0.02-1.53), Mn 7.27 (3.88-11.50), Se 3.19 (1.56-5.85), Sr no mean (<1.50-5.12), Cu 153 (8-1030), Fe 2265 (494-8210), Mg 631 (411-933), Zn 122 (68-337).  In Port Mansfield, early season adults contained significantly more As than those in Port Aransas; early season immatures contained more As than late season immatures; late season adults contained less Fe than those in Chandeleur Sound; early season immatures contained more Fe than late season immatures; late season immatures contained less B than in Port Aransas; late season immatures contained less Mg than either of the other sites.  In Port Aransas, late season adults and immatures contained more Se than early season immatures and adults. 

IV.

Petroleum

1.

In a three day laboratory feeding study, redheads accumulated petroleum hydrocarbons from crayfish exposed to 14C-naphthalene-5% (Tarshis and Rattner, 1982).  The petroleum hydrocarbons were distributed in the tissues as follows (as determined by carbon-14 activity; dpm/g): 5367.4 in blood, 1544.4 in brain, 43810.1 in fat, 55434.7 in gall bladder and bile, 7263.8 in kidney, and 5787.5 in liver.  Activity was significantly greater in fat and gall bladder and bile than in other tissues.  There was also a significant effect of the duration of feeding on concentrations in the blood, brain, kidney, and liver between days 1 and 3 of feeding, indicating a progressive accumulation in tissues.   

2.

Redheads were collected from Port Mansfield, Texas; Port Aransas, Texas; and Chandeleur Sound, Louisiana in November-December 1987, and February-March 1988 (Michot et al., 1994).  Percent detected, mean (range) for hydrocarbon body burden in late-winter male redheads (N=15) ug/g wet weight are as follows: n-dodecane 100, 0.032 (0.02-0.07), n-eicosane 100, 0.054 (0.03-0.10), n-heptadecane 100, 0.151 (0.01-0.61), n-hexadecane 100, 0.058 (0.04-0.10), n-nonadecane 100, 0.085 (0.05-0.14), n-octadecane 100, 0.030 (0.02-0.04), nonylcyclohexane 13, no mean (<0.01-0.01), n-pentadecane 100, 0.174 (0.07-0.28), n-tetradecane 100, 0.348 (0.23-0.60), n-tridecane 100, 0.045 (0.01-0.07), octylcyclohexane 7, no mean (<0.01-0.01), phytane 100, 0.020 (0.01-0.06), pristane 93, 0.047 (<0.01-0.38), pristane:n-heptadecane 93, 0.237 (0-38), pristane:phytane 93, 1.461 (0-19.00), phytane:n-octadecane 100, 0.599 (0.33-2.00), anthacene 13, no mean (<0.01-0.01), benzo(e)pyrene 27, no mean, (<0.01-0.01), chrysene, 47, no mean (<0.01-0.04), fluoranthrene 27, no mean, (<0.01-0.01), napthalene 27, no mean (<0.01-0.01), phenanthrene 73, 0.009 (<0.01-0.01), pyrene 20, no mean (<0.01-0.01).  In Port Aransas, late season adults contained significantly more (p < 0.005) n-hexadecane and nonadecane than those from the other sites. 

V.

Other Contaminants

1.

In 1987 and 1988, 3 redheads were collected from the Ghouspur area of Kot, Sindh, Rawalpindi, Gujranawala, and Seikhupura, in Pakistan ( Afzal and Jafari, 1998 ).  The average number of alpha tracks per square cm were 244 in liver, 313 in kidney, 250 in heart, 247 in lungs, 260 in meat, 257 in bones, 334 in feathers, and 384 in stomach.  The alpha radiation detected was residual from the accident at Chernobyl.   


Redhead Contaminant Response Data

I.

Organochlorine Contaminants

1.

No contaminant data available.

II.

Cholinesterase-Inhibiting Pesticides

1.

In May 1982, 4 mottled ducks were found dead were intentional poisoned with rice seed treated with monocrotophos or dicrotophos in southwestern Matagorda County, Texas ( Flickinger et al., 1984 ). 

III.

Trace Elements, Metals, and Metalloids

1.

In 1968, a redhead was collected from Walpole Island, Lake St. Claire, Ontario, Canada ( Wobeser 1969 ).  It was emaciated, unable to sustain flight, and found to contain 3 Pb shot in its gizzard.  Upon administration of calcium disodium ethylenediaminetetracetate, the bird recovered fully and was released. 

2.

In 1990, a metal fence clip (96% Zn) was endoscopically removed from a 7 month old female redhead diagnosed with Zn toxicity from the Conservation and Research Center (CRC), Front Royal, VA (Zdziarski et al., 1994).  The duck exhibited loss of appetite, depression, loss of weight, weakness, and reluctance to walk.  It was released after 12 days of hospitalization.  A six-year old male redhead diagnosed with Zn toxicity was also collected at the CRC also recovered after endoscopic removal of a metal fence clip. 

3.

One dead redhead was collected from the Couer d’Alene River basin, Idaho ( Sileo et al., 2001 ).  Cause of death was determined to be nonartifactual Pb poisoning with or without other secondary or contributing factors. 

IV.

Petroleum

   1.

From January 1949 through March 1955, dead redheads were collected along the lower Detroit River near a large industrial complex ( Hunt, 1961 ).  One redhead was found dead in a livetrap after an unexpected flow of oil occurred.  A total of 60 dead redheads were collected, 8 were oiled 


References for Redhead

Bellrose, F.C.  1951.  Effects of ingested lead shot upon waterfowl populations.  Sixteenth North American Wildlife Conference, 125-135. 

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.

Flickinger, E.L., D.H. White, C. A. Mitchell, and T. G. Lamont. 1984. Monocrotophos and dicrotophos residues in birds as a result of misuse of organophosphates in Matagorda County Texas USA. J. of the Association of Official Analytical Chemists 67:827-828.

Hebert, C.E., G.D. Haffner, I.M. Weis, R.Lazar, and L. Montour.  1990.  Organochlorine contaminants in duck populations of Walpole Island.  Internat. Assoc. Great Lakes Res. 16:21-26. 

Hunt, G.S.  1961.  Waterfowl losses on the lower detroit river due to oil pollution.  Great Lakes Res.Div., Inst.Sci.& Technol., Univ.Mich.Publ.no.7:10-26.

Mazak, E.J., H.J. MacIsaac, M.R. Servos, and R. Hesslein.  1997.  Influence of feeding habits on organochlorine contaminant accumulation in waterfowl on the Great Lakes.  Ecol. Appl. 7:1133-1143.

Michot, T.C., T.W. Custer, A.J. Nault, and C.A. Mitchell.  1994.  Environmental contaminants in redheads wintering in coastal Louisiana and Texas.  Arch. Environ. Contam. Toxicol. 26:425-434.

Sileo, L., L.H. Creekmore, D.J. Audet, M.R. Snyder, C.U. Meteyer, J.C. Franson, L.N. Locke, M.R. Smith, and D.L. Finley.  2001.  Lead poisoning of waterfowl by contaminated sediment in the Coeur d'Alene River. Arch. Environ. Contam. Toxicol. 41:364-368.

Tarshis, I.B., and B.A. Rattner. 1982. Accumulation of 14C-Naphthalene in the tissues of redhead ducks fed oil contaminated crayfish.  Arch. Environ. Contam. Toxicol. 11:155-159. 

Wobeser, G. 1969. Apparent favorable response of lead poisoning in a duck to treatment with chelating agent.  Bull.Wildl.Dis.Assoc. 5:120.

Zdziarski, J.M., M. Mattix, R.M. Bush, and R.J. Montali.  1994.  Zinc toxicosis in diving ducks.  J. Zoo. Wildl. Med. 25:438-445.

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