Species

Plegadis chihi is 19 inches in length, with a wingspan of 37 inches. Adult males have a mass of approximately 697 grams (Dunning 1993). It is glossy chestnut and purple colored and has a long decurved bill. In summer it has reddish legs and lores, and a white line that goes around the back of the eye and under the chin. (Peterson, 1980)

Status in Estuaries

This species can be found breeding mostly in freshwater marshes, rice fields, ponds, rivers and swamps, although sometimes forages in saltwater (Peterson, 1980, Ehrlich et al., 1988, Kaufman, 1996).  This species nests in small colonies, often with other colonial waterbirds such as black-crowned night-herons, black-necked stilts, and snowy egrets.  Nests are a deeply cupped platform of sticks lined with finer vegetation, built on the ground, over water, or in shrubs, trees, or aquatic vegetation (Ehrlich et al., 1988).  Nests in the northwestern part of the US are built over Scirpus acutus, Typha latifolia, and S. paludosus (Steele, 1984).  Typical clutch size is 3-4 eggs, and young are semialtricial (Ehrlich et al., 1988).  The maximum age of a white-faced ibis recorded in nature is 14 years and 6 months.

Abundance and Range

Year round resident in southern California and the gulf coast of Texas and Louisiana, migratory populations breed in most western states and migrate to southern US and Mexico (Kaufman 1996; Peterson 1980; Steele 1984; Henny et al., 1985).  Range has expanded east since the 1970’s (Kaufman, 1996).  Total North American population has increased since 1970’s but size of local populations fluctuate (Kaufman 1996).  The Breeding Bird Survey estimated over 100,000 in the U.S. in 1997.

Site Fidelity

Nomadic in response to changing environmental conditions; breeding colonies move when water levels become unfavorable (Kaufman 1996; Ryder 1967).

Ease of Census

Although this is a large colonial nesting bird, census is difficult because colonies are not easy to locate, aerial estimates of dark colored ground nesting birds are not reliable, and nesting is not perfectly synchronous throughout a colony, so new nests can appear after ground surveys (Steele 1984).

Feeding Habits

Usually feeds on aquatic invertebrates such as crayfish, insects and insect larvae (Libbellulidae, Tabanidae, and Lepidoptera), earthworms, fish, snails, leeches, spiders, small vertebrates, and occasionally, aquatic vegetation (Ehrlich et al., 1988; Henny and Herron, 1989; Kaufman 1996).  Mostly forages in shallow water by probing in mud or picking food items off water surface or plants (Kaufman, 1996).  

White-Faced Ibis Contaminant Exposure Data

I.

Organochlorine Contaminants

A.

Concentrations in Adults and Juveniles

1.

On July 19, 1970, 4 dead and 3 dying 2-4 week old ibis were collected from the Lavaca Bay nesting colony on the Texas gulf coast (Flickinger and Meeker 1972).  Concentrations in brain were 8.0, 6.3, 5.8, 4.8, 4.6, 0.5, and 0.4 ug/g dieldrin and 0.2, 0.3, 0.5, 0.7, 0.5, 0.2, and 0.1 ug/g DDE.  Concentration in carcass (minus brain and kidney) were 6.7, 4.5, 3.3, 1.7, 2.7, 0.3, and 1.1 ug/g dieldrin and 0.2, 0.3, 0.3, 0.2, 0.2, 0.2, and 0.4 ug/g DDE.

2.

Adult ibis were shot near Lavaca Bay, Texas (N=10) in 1971 (King et al., 1980).  Brains contained 0.24 ug/g wet weight DDE and 0.67 ug/g dieldrin; a pooled sample of 10 brains was not significantly different. Whole body concentrations were 0.51 ug/g DDE and 1.52 ug/g dieldrin; a pooled sample of 10 whole bodies was similar.  In 1973, 3 of 38 dead or dying birds contained 6.3, 8.1, and 25.0 ug/g dieldrin in brain. 

3.

Adult ibis (N=61) were collected from marshes in the Bear River delta, Box Elder, County, Utah in 1974 and 1975 (Capen and Leiker, 1979).  Mean DDE concentrations for birds collected in May-June, in males and females, respectively were: 0.102 (N=13) and 0.177 (N=21) ug/g wet weight in blood sera; 20.7 (N =13) and 23.9 (N =21) ug/g lipid weight in subcutaneous fat; and 28.4 (N =2) and 28.7 (N =6) ug/g lipid weight in breast muscle.  Mean DDE concentrations for July-August were: 0.515 (N=16) and 0.186 (N=11) ug/g wet weight in blood sera; 20.5 (N=3) and 14.0 (N=5) ug/g lipid weight in subcutaneous fat; and 54.7 (N=9) and 21.3 (N=6) ug/g lipid weight in breast muscle.  Blood DDE was significantly different between males and females.  A significant relationship was found between DDE in blood and fat, and DDE in blood and muscle.  DDE concentrations in blood were elevated in July samples when lipids were at their lowest, and related to concentrations in muscle lipid.

B.

Concentrations in Eggs

1.

Eggs were collected between 1969 and 1976 on 2 islands in Texas, Dressing Point in East Matagorda Bay, and an unnamed island in Lavaca Bay (King et al., 1980).  Randomly collected eggs in 1970 (N=10) contained 0.3-2.2 ug/g DDE, <0.1-0.4 ug/g dieldrin, and Aroclor 1254 was not detected.  Thin-shelled eggs collected in 1970 (N=13) contained 0.14-14.4 ug/g DDE, <0.1-2.2 ug/g dieldrin, and ND-4.0 ug/g Aroclor 1254.  Eggs collected in 1971 were pooled by clutch size.  One-egg clutches contained 6.5 ug/g DDE, 1.9 ug/g dieldrin, and 1.5 ug/g Aroclor 1254; 3-egg clutches contained 1.0 ug/g DDE, 1.4 ug/g dieldrin, and 1.5 ug/g Aroclor 1254.  A random sample of 20 eggs collected in 1976 contained 0.25 ug/g DDE  (N=19), 0.71 ug/g dieldrin (N=17), 0.43 ug/g Aroclor 1260, 0.14 ug/g chlordane (N=8), 0.08 ug/g HCB (N=4), 0.12 ug/g endrin (N=1), and 0.38 ug/g mirex (N=1).

2.

In 1979, ibis eggs were collected from 3 marshes in Box Elder County, Utah: Bear River National Wildlife Refuge, The Bear River Club, and Knudson’s marsh (Steele 1984).  Mean (range) concentrations of organic contaminants (N=number of detects out of 80 analyzed eggs) were (ug/g wet weight): DDE (n=80) 1.25, Aroclor 1254 (n=68) 0.25, DDT (n=48) 0.14, dieldrin (n=42) 0.12, heptachlor epoxide (n=27) ND-0.94, oxychlordane (n=27) ND-0.19, beta-BHC (n=27) ND-0.56, DDD (n=25) ND-0.65, endrin (n=12) ND-0.15, nona-chlordane (n=7) ND-0.14, HCB (n=5) ND-0.11, alpha-BHC (n=3) ND- 0.07, and mirex (n=1) 0.06. 

3.

From 1979-1983, eggs were collected from 90 nests in Carson Lake, Nevada; Ruby Lake, Nevada; Malheur Lake, Oregon; and Stillwater, Nevada (Henny et al., 1985) Mean DDE concentrations in ug/g (% occurance over 3 ug/g) 1.62 (40%), 2.23 (33%), 0.54 (6%), and 1.71 (40%) ug/g from Carson Lake in 1980-83 samples were; 1.09 (13%) ug/g in Ruby Lake in 1979; 1.27 (13%) ug/g in Malheur Lake in 1980, and 0.52 (17%) ug/g in Stillwater in 1981.  Dieldrin and DDT were detected in eggs from Carson Lake, Ruby Lake, and Malheur Lake; chlordane and endrin in eggs from Carson Lake and Ruby Lake; and toxaphene and HCB in eggs from Carson Lake and Malheur Lake.  PCBs were detected in 2 eggs, and beta-BHC was detected in 5 eggs from Ruby Lake in 1979. All chemicals were detected in < 50% of samples, with the exception of DDE in eggs collected from Carson Lake in all years, and DDT in eggs collected from Carson Lake in 1980 and 1981. 

4.

Eggs were collected from Carson Lake, Nevada in 1985 (3 groups of 20) and 1986 (4 groups 20) (Henny and Herron, 1989).  Mean DDE ranged from 1.53-3.47 ug/g wet weight, and the highest single concentrations each year ranged from 9-29 ug/g. DDE concentrations > 4 ug/g were detected in 52% of eggs from 1985, and 35% from 1986.  The percent occurrence of chemicals for 1985 and 1986, respectively was: DDT 18% and 41%, dieldrin 48% and 37%, heptachlor epoxide 2% and 15%, oxychlordane or trans-nonachlor 0% and 11%, toxaphene 2% and 18%, HCB not analyzed in 1985 and 33%, and endrin 17% and 20%.  

5.

Twenty eggs were collected from two colonies on dredge spoil islands in the Lower Laguna Madre, one near Port Mansfield and the other east of Arroyo City near Green Island (Custer and Mitchell, 1989).  Mean (range) DDE for Port Mansfield and Green Island eggs, respectively were: 0.14 (nd-3.1; 5 detects) ug/g wet weight, and 0.27 (0.14-0.87) ug/g. 

6.

Twenty eggs were collected from Carson Lake, Nevada in 1996 (Henny 1997).  Mean DDE was 2.66 ug/g wet weight, with a maximum of 12 ug/g.  The percent occurrence of chemicals was: DDE > 4 ppm 45%, DDT 60%, dieldrin 0%, heptachlor epoxide 0%, oxychlordane, trans-nonachlor and cis-nonachlor 5%, HCB 10%, endrin 0%, PCBs 0%.  Concentrations of DDE, incidence of DDE ≥ 4 ppm and DDT ≥ 0.10 did not decrease compared to those reported for 1985 and 1986.  All chemicals other than DDE and DDT were detected in concentrations <0.1 ug/g. 

II.

Cholinesterase-Inhibiting Pesticides

No direct exposure data available

III.

Trace Elements, Metals, and Metalloids

1.

Eggs were collected between 1971 and 1976 on 2 islands in Texas, Dressing Point in East Matagorda Bay, and an unnamed island in Lavaca Bay (King et al., 1980).  Eggs collected in 1971 were pooled by clutch size and contained 0.12 ug/g Hg in 1-egg clutches and 0.21 ug/g Hg in 3-egg clutches.  A random sample of 20 eggs collected in 1976 contained 0.11 ug/g Hg, 0.012 ug/g As, and 0.61 ug/g Se.

2.

Adults shot near Lavaca Bay, Texas had mean concentration of 1.72 ug/g Hg in whole body (King et al., 1980). 

3.

In 1970, 4 dead 2-4 week olds collected from the Lavaca Bay nesting colony on the Texas gulf coast had renal Hg concentrations of 0.98, 2.00, 1.60, and 1.75 ug/g (Flickinger and Meeker, 1972).  . 

4.

Eggs were collected from Carson Lake, Nevada in 1985 (3 groups of 20) and 1986 (4 groups 20), along with 18 whole adult ibis (Henny and Herron, 1989).  The 7 collection groups contained 0.22, 0.77, 0.47, 0.43, 0.70, and 1.09 ug/g dry weight Hg and 3.29, 5.40, 2.95, 1.91, 2.75, and 2.77 ug/g Se.  One unhatched egg containing a malformed embryo contained 1.7 ug/g Hg and 2.3 ug/g Se.  Mean (range) concentrations in were: males (n=9) 27.0 (0.78-87) ug/g Hg; 10.7 (5.0-27) ug/g Se, 0.28 (ND-0.58) ug/g As, 1.8 (ND-6) ug/g B, 2.6 (1.7-4.2) ug/g Cd; females (n=9) 19.8 (8.6-36) ug/g Hg, 8.6 (5.7-12) ug/g Se, 0.47 (0.30-1.0) ug/g As; 3.1 (ND-11) ug/g B, and 2.4 (0.80-4.3) ug/g Cd.  Lead was detected in 10/18 livers and was <0.65 ug/g in all but 2 (3.9 ug/g, male; 4.5 ug/g, female). 

5.

Of twenty eggs collected from Carson Lake, Nevada in 1996, Hg was detected in 5, at a mean concentration of 0.72 ug/g wet weight (Henny 1997). 

IV.

Petroleum

No residue data available

V.

Other

No residue data available

White-Faced Ibis Contaminant Response Data

I.

Organochlorine Contaminants

1.

Between 1969 and 1976 eggs and adults were collected on 2 islands in Texas: Dressing Point in East Matagorda Bay, and an unnamed island in Lavaca (King et al., 1980).  Mean eggshell thicknesses from randomly collected eggs were: before 1943 museum collections (n=18) 0.312; 1970 (n=86) 0.301; 1971 (n=30) 0.282; 1972 (n=34) 0.293; 1973 (n=20) 0.293; 1974 (n=20) 0.295; 1975 (n=20) 0.284; 1976 (n=20) 0.298.  Eggshell thickness for abnormal eggs was 6 to 32% less than pre-1943 thickness.  DDE was negatively correlated with eggshell thickness.  The population on the Texas coast decreased from 9,200 in 1969 to 2,100 in 1974, and increased to 5,300 in 1976; fluctuations were not entirely explained by weather.  Mean clutch size between 1971-1976 was 2.7 (museum collection average was 3.7, may have been biased), possibly due to eggshell thinning and collapse.  Before eggs hatched in 1973, 11 of 49 nests were abandoned, and recruitment was <1 young per pair.  The author suggests that the timing of application of aldrin treated rice seed to the feeding grounds may have affected production.

2.

Between May and July of 1970, observations were made at 3 ibis colonies on the Texas Gulf coast: mainland at Willie Slough, and islands in Matagorda and Lavaca Bays (Flickinger and Meeker, 1972).  There were sick or dead young in 150 nests at Matagorda Bay on May 22, a few hundred dead young at Wille Slough on July 11, and several hundred dead and a few sick young at Lavaca Bay on July 19.  Young ibis were showing muscular weakness, jerkiness in gait, fluffed feathers, drooping wings, loss of muscular coordination or immobility, violent body tremors, neck arched far over back, and terminal wing-beat convulsions, characteristic of dieldrin poisoning.  Adults were obtaining food from rice fields treated with aldrin, methymercury 2,3-dihydroxypropyl mercaptide, and methylmercury acetate.

3.

In 1979, eggs were collected from 3 marshes in Box Elder County, Utah: Bear River National Wildlife Refuge, The Bear River Club, and Knudson’s marsh (Steele 1984).  Mean eggshell thickness (0.313 mm; N=176) was negatively correlated to DDE concentrations. Clutch size, hatching success, and chicks per nest (not adjusted for collected egg) were classified by DDE and DDT concentrations: DDE < or = 1.50 ug/g (N=42): 3.45, 71%, 1.76; DDE 1.51-3.00 ug/g (N=22): 3.18, 74%, 1.64; DDE > 3.00 ug/g (N =16): 3.13, 57%, 1.25; DDT < or = 0.25 ug/g (N=64): 3.36, 71%, 1.70; DDT 0.26-0.50 ug/g (N =6): 3.33, 75%, 1.67; DDT > 0.50 ug/g (N =7): 3.00, 45%, 0.86.  Elevated DDE concentrations were correlated with later nest initiation dates, reduced clutch size, reduced reproduction of chicks, and reduced hatching success.  Cracked eggs were found in 3.9% of 1198 nests in 1978, and in 1.5% of 5231 nests in 1979. 

4.

From 1979-1983, eggs were collected 90 nests in Carson Lake, Nevada; Ruby Lake, Nevada; Malheur Lake, Oregon; and Stillwater, Nevada (Henny et al., 1985).  Mean eggshell thickness was 0.295, 0.288, 0.310, and 0.285 mm from Carson Lake 1980-83 samples, 0.301 mm from Ruby Lake in 1979, 0.308 mm from Malheur Lake in 1980, and 0.305 mm from Stillwater in 1981.  Eggshell thickness was correlated with DDE concentrations, and thinning ranged from 5.2% to 12.8% (yearly averages), with the highest thinning observed at 27.8%.  The incidence of clutches with cracked eggs was reported by DDE concentration: DDE ≤1 ug/g: 1/37; DDE 1.01-4.0 ug/g: 2/38; DDE 4.01-8.0 ug/g: 2/8, DDE 8.01-16.0 ug/g: 2/4, and DDE 16.01-20.0 ug/g, 3/4.  The authors suggest that eggshell cracking becomes a problem at DDE >4 ug/g.

5.

Eggs were collected from Carson Lake, Nevada in 1985 (3 groups of 20) and 1986 (4 groups 20) (Henny and Herron 1989).  Eggshell thickness ranged from 0.261-0.287 mm, and DDE was negatively correlated with eggshell thickness.  A total of 14.3% of nests had cracked eggs.  The percent of nests with cracked eggs categorized by concentration of DDE was: 1 ug/g: 0%, 1.01-4.0 ug/g: 5.1%, 4.01-8.0 ug/g: 5.0%, 8.01-16.0 ug/g: 39.3%,  and >16 ug/g: 54.5%.  DDE was negatively correlated with young produced per nesting attempt and young produced per successful nest.  The mean number of young per successful nest was 1.84 and the mean young per nesting attempt was 1.43 (does not account for collected eggs). 

6.

Twenty eggs were collected from two colonies on dredge spoil islands in the Lower Laguna Madre: one near Port Mansfield and one east of Arroyo City near Green Island (Custer and Mitchell, 1989).  Mean eggshell thickness was 0.306 mm at Port Mansfield and 0.295 mm at Green Island, and was not correlated with DDE concentrations.

7.

Twenty eggs collected from Carson Lake, Nevada in 1996 had a mean eggshell thickness was 0.267 mm, which was correlated to  (Henny 1997).  Eggshell thickness was correlated with DDE concentrations. 

II.

Cholinesterase-Inhibiting Pesticides

No response data available

III.

Trace Elements, Metals, and Metalloids

1.

An unhatched egg was collected from Carson Lake, Nevada in 1985 contained 1.7 ug/g Hg and 2.3 ug/g Se (Henny and Herron, 1989).  The embryo had no right eye, a small slit for the left eye, and the lower bill was longer than the upper bill. 

IV.

Petroleum

No response data available

V.

Other

No response data available

References for White-Faced Ibis

Capen, D.E. and T.J. Leiker.  1979.  DDE residues in blood and other tissues of white-faced ibis.  Environ. Pollut. 19:163-171. 

Custer, T.W. and C.A. Mitchell.  1989.  Organochlorine contaminants in white-faced ibis eggs in southern Texas.  Colon. Waterbirds 12:126-129. 

Flickinger, E.L. and D.L. Meeker.  1972.  Pesticide mortality of young white-faced ibis in Texas.  Bull. Environ. Contam. Toxicol. 8:165-168. 

Henny, C.J.  1997.  DDE still high in white-faced ibis eggs from Carson Lake, NV.  Colon. Waterbirds 20:478-484. 

Henny, C.J. and G.B. Herron.  1989.  DDE, selenium, mercury, and white-faced ibis reproduction at Carson Lake, NV.  J. Wildl. Manage. 53:1032-1045. 

Henny, C.J., L.J. Blus, and C.S.Hulse. 1985. Trends and effects of organochlorine residues on Oregon and Nevada wading birds, 1979-83.  Colon. Waterbirds 8:117-129. 

King, K.A., D.L. Meeker, and D.M. Swineford.  1980.  White-faced ibis populations and pollutants in Texas, 1969-1976.  Southwest. Nat. 25:225-240.

Steele, B.B.  1984.  Effects of pesticides on reproductive success of white-faced ibis in Utah, 1979.  Colon. Waterbirds 7:80-87.