Animal Diversity Web

Ge­o­graphic Range

White-faced ibises are wide­spread, with two dis­tinct ranges; one pop­u­la­tion is found in North and Mid­dle Amer­ica and a sep­a­rate pop­u­la­tion is found in South Amer­ica. Those found in North and Mid­dle Amer­ica cover most of the west­ern and mid-west­ern United States and most of Mex­ico. Breed­ing areas are as far north as south­ern Canada and as far east as Ne­braska. Ad­di­tion­ally they are found along the Gulf coast of Texas and Louisiana and in cen­tral Mex­ico. How­ever, all ex­cept those found in Cal­i­for­nia, Texas, Louisiana and cen­tral Mex­ico will mi­grate to south­ern parts of their range dur­ing the non-breed­ing sea­son. Most of these win­ter in Mex­ico but other pop­u­la­tions mi­grate to Guatemala, El Sal­vador and Hon­duras. South Amer­i­can pop­u­la­tion of white-faced ibises do not mi­grate for the win­ter. They are found from south­ern Brazil and south­east­ern Bo­livia to north­ern Ar­gentina. The east­ern and west­ern bound­aries of their range are the Pa­cific and At­lantic Oceans. (BirdLife In­ter­na­tional 2004, 2006; Han­cock, et al., 1992; Na­ture­Serve, 2006; Ryder and Manry, 2005; Zaun, et al., 2003)

• Biogeographic Regions
• nearctic
  • native
• neotropical
  • native

Habi­tat

White-faced ibises are found in both tem­per­ate and trop­i­cal re­gions. They tend to live in fresh and salt­wa­ter marshes con­tain­ing many rushes and sedges which are used to nest on, for nest­ing ma­te­ri­als, and for find­ing food. These birds are also found around ponds, rivers and in flooded pas­tures and agri­cul­tural fields. Rainy con­di­tions are re­quired for both for­ag­ing and nest­ing rainy con­di­tions are re­quired, lim­it­ing the areas in which they are found and in­flu­enc­ing move­ment pat­terns. White-faced ibises are found from near sea level to 4300 m el­e­va­tion in South Amer­ica. (Han­cock, et al., 1992; Ryder and Manry, 2005)

• Habitat Regions
• temperate
• tropical
• terrestrial

• Aquatic Biomes
• lakes and ponds
• rivers and streams

• Wetlands
• marsh

• Other Habitat Features
• agricultural
• riparian

• Range elevation

  0 to 4300 m

  0.00 to 14107.61 ft

Phys­i­cal De­scrip­tion

White-faced ibises weigh be­tween 450 and 525 grams and are 46 to 56 cm in length. Those found in South Amer­ica tend to be smaller than those found in North Amer­ica. When white-faced ibises first hatch they are bare on the un­der­side and sparsely cov­ered with brown or black down. After about two weeks they start to gain their ju­ve­nile plumage, which con­sists of the loss of down and gain­ing green and pur­ple col­ored feath­ers. Ju­ve­niles are also no­tice­ably smaller than adults. Adults are dark in color, ei­ther ma­roon or brown with dark green re­flec­tions on the un­der­side. Dur­ing mat­ing sea­son the head, neck, upper back, wing-coverts and un­der­side be­comes more chest­nut in color. In both breed­ing and non­breed­ing sea­sons there is a metal­lic green look to the flight feath­ers. These ibises get their name from the white col­or­ing, which can be seen on their face and throat. Males have the same col­or­ing as fe­males but males are gen­er­ally big­ger than fe­males. Parts of the face, as well as the legs and feet are red or pur­ple be­cause bare skin is ex­posed. The length of the bill varys be­tween 15 and 18 cm, males have longer bills than fe­males. There are no de­scribed sub-species. (Anony­mous, 2003; Han­cock, et al., 1992; Ryder and Manry, 2005)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  450 to 525 g

  15.86 to 18.50 oz

• Range length

  46 to 56 cm

  18.11 to 22.05 in

• Range wingspan

  94 to 99 cm

  37.01 to 38.98 in

Re­pro­duc­tion

If con­di­tions are fa­vor­able, the mat­ing process be­gins shortly after white-faced ibises re­turn from their win­ter­ing lo­ca­tions. If con­di­tions are not fa­vor­able, mat­ing can be de­layed tem­porar­ily or not un­der­taken at all in that year. Nest­ing oc­curs in dense, large colonies. It is un­known when the male and fe­male bond. Some ap­pear to re­turn from win­ter­ing lo­ca­tions al­ready as mated pairs, some seem to form pairs in the one or two weeks pro­ceed­ing mat­ing. It is also un­known how long this pair­ing lasts. Males dis­play at mul­ti­ple pos­si­ble nest­ing sites, in­clud­ing pre­vi­ously used nests. Males use “rit­u­al­ized bill prob­ing” and also give a call that in­ter­ested fe­males an­swer with an­other call. Fe­males choose the ac­tual nest­ing site. (Han­cock, et al., 1992; Ryder and Manry, 2005)

• Mating System
• monogamous

White-faced ibises breed once per year. The breed­ing sea­son in North Amer­ica is from April to May. In the event of un­fa­vor­able breed­ing con­di­tions, this sea­son can some­times last until mid-June or the sea­son can be skipped al­to­gether. In South Amer­ica the breed­ing sea­son oc­curs in No­vem­ber and De­cem­ber. Eggs are laid at a one to two day in­ter­val with the av­er­age num­ber of eggs laid each sea­son being three to four and a range of two to seven. The eggs hatch after 20 days (range: 17 to 26). Be­fore the young can fly on their own they are fed by their par­ents. Dur­ing the first week after hatch­ing there is a 60% mor­tal­ity rate for third and fourth eggs pro­duced, com­pared with a 5% mor­tal­ity rate for first and sec­ond eggs. Young fledge after five weeks and are in­de­pen­dent after eight weeks. (Anony­mous, 2003; Han­cock, et al., 1992; Ryder and Manry, 2005; Taft, et al., 2000; Zaun, et al., 2003)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• oviparous

• Breeding interval

  White-faced ibises breed once yearly.

• Breeding season

  Nesting generally occurs April to June in North America and November to December in South America.

• Range eggs per season

  2 to 7

• Average eggs per season

  3.5

• Average eggs per season

  3

  AnAge

• Range time to hatching

  17 to 26 days

• Average time to hatching

  20 days

• Average fledging age

  5 weeks

• Average time to independence

  8 weeks

• Average age at sexual or reproductive maturity (female)

  2 years

• Average age at sexual or reproductive maturity (male)

  2 years

White-faced ibis par­ents take turns in mak­ing the nest and guard­ing it. The male starts guard­ing the nest while the fe­male gath­ers ma­te­ri­als and then the role re­verses while the fe­male builds the nest the male gath­ers ma­te­ri­als. Once the eggs have been laid, the par­ents take turns in car­ing for the eggs, nor­mally the males dur­ing the day and the fe­males at night. Both sexes will fiercely guard the nest and the area around the nest within a meter against in­trud­ers. They shade or in­cu­bate the eggs to keep them at the cor­rect tem­per­a­ture. This treat­ment con­tin­ues for the first week fol­low­ing hatch­ing and oc­curs to a lesser ex­tent (left alone for up to three hours) dur­ing the sec­ond week and is ab­sent in the third week. Both male and fe­male adults will feed the young. This is done by re­gur­gi­tat­ing par­tially di­gested food. The par­ents will also take the young on both a short walk and a short flight around the colony. There is no ev­i­dence to be­lieve there is an as­so­ci­a­tion be­tween the par­ents and young after they have reached in­de­pen­dence. (Han­cock, et al., 1992; Ryder and Manry, 2005)

• Parental Investment
• altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female

Lifes­pan/Longevity

The longest known lifes­pan of this species in the wild is 14 years and 6 months. In cap­tiv­ity they have lived to 14 years. In a study done in Utah in 1967, 111 birds that had been tagged at birth were re­cov­ered, all of which died by the age of 9. (Ryder and Manry, 2005)

• Range lifespan
  Status: wild

  14.5 (high) years

• Range lifespan
  Status: captivity

  14 (high) years

• Typical lifespan
  Status: wild

  9 (high) years

Be­hav­ior

White-faced ibises are so­cial and no­madic. If a for­ag­ing area be­comes too dry they will leave in search of a more suit­able lo­ca­tion. White-faced ibises fly rel­a­tively long dis­tances to find food. They fly at a rate of about 48 to 53 km per hour, they fly in a V for­ma­tion with other birds for ef­fi­ciency. Par­ents will shade their young while they are in the nest from the sun when it is hot out as the young tend to die quickly of heat ex­po­sure. These birds are gre­gar­i­ous, liv­ing in large groups. They are tol­er­ant of other ibises out­side of the breed­ing sea­son. Dur­ing the breed­ing sea­son they will de­fend an area of about one meter around their nest, the av­er­age nest is two me­ters away from its neigh­bors. Some­times land­ing and preen­ing perches 3 me­ters away will also be de­fended. White-faced ibises for­age in flocks, tak­ing ad­van­tage of in­sects and other food items dis­turbed by con­specifics. (Anony­mous, 2003; At­ten­bor­ough, 1998; Han­cock, et al., 1992; Ryder and Manry, 2005)

• Key Behaviors
• terricolous
• flies
• glides
• diurnal
• motile
• nomadic
• migratory
• territorial
• social
• colonial

• Range territory size

  0.5 to 10 m^2

• Average territory size

  2 m^2

Home Range

White-faced ibises de­fend small areas around nests dur­ing the breed­ing sea­son. Out­side of the breed­ing sea­son, they for­age over large areas in flocks. The size of these for­ag­ing areas has not been re­ported.

Com­mu­ni­ca­tion and Per­cep­tion

White-faced ibises com­mu­ni­cate through sounds and vi­sual dis­plays. There are mul­ti­ple dif­fer­ent sounds that these birds make which have dif­fer­ent mean­ings. There are sep­a­rate sounds for call­ing to their young, when a mate is re­turn­ing to the nest, and a sound used as a feed­ing call. (Han­cock, et al., 1992; Ryder and Manry, 2005)

• Communication Channels
• visual
• acoustic

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

White-faced ibises feed by prob­ing the sub­strate with their long bill, in search of small an­i­mals. They feed in large groups of up to 1000 in­di­vid­u­als. They feed mainly in moist areas around bod­ies of water and also in shal­low (less than 20 cm) water. They are pri­mar­ily car­niv­o­rous and feed on in­sects, crus­taceans, spi­ders, snails, leeches, and am­phib­ians. Snails and slugs are the large prey group by vol­ume, ac­count­ing for 55 to 90% of all food eaten. Prey taken varies with the sea­son, with more in­sects in the spring and sum­mer than in other sea­sons. Males tend to eat more snails and slugs and fe­males tend to eat more in­sects. (Han­cock, et al., 1992; Ryder and Manry, 2005; Soave, et al., 2006)

• Primary Diet
• carnivore
  • insectivore
  • molluscivore

• Animal Foods
• amphibians
• insects
• terrestrial non-insect arthropods
• mollusks
• terrestrial worms
• aquatic crustaceans

Pre­da­tion

The eggs, nestlings, and fledg­lings of white-faced ibises are taken by many dif­fer­ent preda­tors, in­clud­ing gull species (Larus), black-billed mag­pies (Pica pica), black-crowned night herons (Nyc­ti­co­rax nyc­ti­co­rax), com­mon ravens (Corvus corax), rac­coons (Pro­cyon lotor), striped skunks (Mephi­tis mephi­tis), spot­ted skunks (Spi­lo­gale puto­rius), coy­otes (Canis la­trans), mink (Neo­vi­son vison), and long-tailed weasels (Mustela fre­nata). Mam­mals are more likely to be­come preda­tors when water lev­els around nests fall, mak­ing ac­cess to the nest eas­ier. Pere­grine fal­cons (Falco pere­gri­nus) and red-tailed hawks (Buteo ja­maicen­sis) are able to prey on the adult white-faced ibises, but Ryder and Manny (2005) re­port that pre­da­tion on adults is rare. Hu­mans (Homo sapi­ens) are major preda­tors of white-faced ibises, for food, feath­ers, and sport. Adults are vig­i­lant in pro­tect­ing their eggs and young from preda­tors, help­ing to avoid pre­da­tion. Their flock­ing habits also help in alert­ing flock mem­bers to po­ten­tial dan­ger. (Han­cock, et al., 1992; Ryder and Manry, 2005)

• Known Predators

  • peregrine falcons (Falco peregrinus)
  • red-tailed hawks (Buteo jamaicensis)
  • long-tailed weasels (Mustela frenata)
  • spotted skunks (Spilogale putorius)
  • coyotes (Canis latrans)
  • mink (Neovison vison)
  • striped skunks (Mephitis mephitis)
  • humans (Homo sapiens)
  • black-billed magpies (Pica pica)
  • gull species (Larus)
  • black-crowned night herons (Nycticorax nycticorax)
  • common ravens (Corvus corax)
  • raccoons (Procyon lotor)

Ecosys­tem Roles

White-faced ibises aer­ate the soil with their for­ag­ing method of push­ing their bill into the ground. They are im­por­tant preda­tors of many aquatic in­ver­te­brate groups, im­pact­ing their pop­u­la­tions. Ad­di­tion­ally, they are the hosts of sev­eral species of par­a­sites: Arde­icola rhaphid­ius, Ci­coniphilus blagoweschen­skii, Colpocephalum lep­topy­gos, Ibi­doe­cus bisig­na­tus, and Ple­gadiphilus ple­gadis. (Ryder and Manry, 2005)

• Ecosystem Impact
• soil aeration

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Ibises are hunted for food in some areas. They are also im­por­tant for bird­ing eco­tourism and are es­sen­tial com­po­nents of the healthy, wet­land habi­tats in which they live. (Han­cock, et al., 1992)

• Positive Impacts
• food
• body parts are source of valuable material
• ecotourism

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

White-faced ibises some­times have an eco­nomic im­pact on farm­ers be­cause they can tram­ple crops in wet fields dur­ing for­ag­ing. Cray­fish farm­ers ex­pe­ri­ences losses when white-faced ibises visit their op­er­a­tions. (Ryder and Manry, 2005)

• Negative Impacts
• crop pest

Con­ser­va­tion Sta­tus

White-faced ibises have a large ge­o­graphic range and pop­u­la­tions re­main large. Pop­u­la­tion trends haven't been quan­ti­fied, but pop­u­la­tions are be­lieved to be sta­ble cur­rently.

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Migratory Bird Act

  Protected

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Matthew Gum­ble­ton (au­thor), Kala­ma­zoo Col­lege, Ann Fraser (ed­i­tor, in­struc­tor), Kala­ma­zoo Col­lege.

Ref­er­ences

Amat, J., F. Rilla. 1994. For­ag­ing Be­hav­ior of White-Faced Ibises (Ple­gadis chihi) in Re­la­tion to Habi­tat, Group Size, and Sex. Colo­nial Wa­ter­birds, 17/1: 42-49.

Anony­mous, 2003. "White-faced Ibis" (On-line). An­i­mal Field Guide. Ac­cessed Oc­to­ber 16, 2006 at http://​fwp.​mt.​gov/​fieldguide/​detail_​ABNGE02020.​aspx.

At­ten­bor­ough, D. 1998. The Life of Birds. New Jer­sey: Prince­ton Uni­ver­sity Press.

Bild­stein, K. 1993. White Ibis. Wash­ing­ton and Lon­don: Smith­son­ian In­sti­tu­tion Press.

BirdLife In­ter­na­tional 2004, 2006. "Ple­gadis chihi" (On-line). The IUCN Redlist of Threat­ened Species. Ac­cessed Oc­to­ber 16, 2006 at http://​www.​iucnredlist.​org/​search/​details.​php/​49621/​summ.

Blanco, G., R. Ro­driguez-Es­trella. 1998. Human Ac­tiv­ity May Benifit White-Faced Ibises Over­win­ter­ing in Baja, Cal­i­for­nia Sur, Mex­ico. Colo­nial Wa­ter­birds, 21/2: 274-276.

Han­cock, J., J. Kush­lan, M. Kahl. 1992. Storks, Ibises and Spoon­bills of the World. Great Bri­tan: Har­court Brace Jo­vanovich.

Na­ture­Serve, 2006. "Ple­gadis chihi" (On-line). Com­pre­hen­sive Re­port Species. Ac­cessed Oc­to­ber 16, 2006 at http://​www.​natureserve.​org/​explorer/​servlet/​NatureServe?​searchName=Plegadis+chihi.

Ryder, R., D. Manry. 2005. "White-faced Ibis" (On-line). Birds of North Amer­ica On­line. Ac­cessed No­vem­ber 14, 2006 at http://​bna.​birds.​cornell.​edu/​BNA/​account/​White-faced_​Ibis/​INTRODUCTION.​html.

Soave, G., A. Camperi, C. Dar­rieu, A. Ci­cchino, V. Fer­retti. 2006. White-faced Ibis Diet in Ar­gentina. Wa­ter­birds, 29/2: 191–197. Ac­cessed Oc­to­ber 16, 2006 at http://​www.​bioone.​org/​perlserv/?​request=get-document&​doi=10.​1675%2F1524-4695%282006%2929%5B191%3AWIDIA%5D2.​0.​CO%3B2.

Taft, M., D. Mauser, T. Arnold. 2000. Breed­ing Ecol­ogy Of White-Faced Ibis (Plea­gadis Chihi) In The Upper Kla­math Basin, Cal­i­for­nia. West­ern North Amer­i­can Nat­u­ral­ist, 60/4: 403-409.

Zaun, B., K. King, C. Hurt, M. Schot­borgh. 2003. First Record Of White-Faced Ibis, Ple­gadis Chihi, Nest­ing In Ari­zona. The South­west­ern Nat­u­ral­ist, 48/1: 130-131. Ac­cessed Oc­to­ber 16, 2006 at http://​www.​bioone.​org/​perlserv/?​request=get-document&​doi=10.​1894%2F0038-4909%282003%29048%3C0130%3AFROWIP%3E2.​0.​CO%3B2.