Animal Diversity Web

Ge­o­graphic Range

Phalaro­pus tri­color are found in North Amer­ica dur­ing breed­ing sea­son. They are lo­cated in the north­west United States and the west­ern part of Canada. Within Canada, this species is found as far north as the Great Slave Lake, which is lo­cated in the North­west Ter­ri­to­ries. Oc­ca­sion­ally, Wil­son's phalaropes can be found in iso­lated pop­u­la­tions scat­tered along the en­tire length of the United States and Canada bor­der that sur­rounds the Great Lakes.

Dur­ing non breed­ing sea­son, Wil­son's phalaropes are found in the en­tire south­ern por­tion of South Amer­ica as well as the west­ern coast ex­tend­ing from Lima, Peru north­ward to Es­mer­al­das, Ecuador. (An­drei, et al., 2006; BirdLife In­ter­na­tional, 2012; Jehl, 1999)

• Biogeographic Regions
• nearctic
  • native
• neotropical
  • native

Habi­tat

Dur­ing the breed­ing sea­son, Wil­son's phalaropes nest in fresh­wa­ter marshes. Dur­ing mi­gra­tion this bird species is found near ponds, in flooded fields, mud flats, along lake shores, and in ri­par­ian habi­tats. Oc­ca­sion­ally, this species can also be found near sewage treat­ment plants dur­ing mi­gra­tion be­cause of the sewer water. Dur­ing the win­ter months, Wil­son phalaropes are mainly found near al­ka­line lakes and ponds in South Amer­ica. The el­e­va­tion of this species is sea level up to 300m. (Jehl, 1999; Roesler and Im­berti, 2015; Sk­a­gen, 1994)

• Habitat Regions
• freshwater

• Aquatic Biomes
• lakes and ponds
• temporary pools

• Wetlands
• marsh

• Range elevation

  0 to 300 m

  0.00 to 984.25 ft

Phys­i­cal De­scrip­tion

Wil­son's phalaropes are shore­birds with long legs and pointed wings. This bird species has a slim neck and a long, straight bill. Male and fe­male Wil­son's phalaropes are 22cm to 24cm in length and have wingspans of 39cm to 43cm. Fe­males tend to weigh more than males. The weight of male Wil­son's phalaropes ranges from 38g to 110g, while fe­males range from 52g to 128g. The slen­der build of Wil­son's phalaropes helps dis­tin­guish them from other closely-re­lated shore­birds such as Scolopaci­dae or more com­monly known as sand­piper.

Non-breed­ing Wil­son's phalaropes are mainly white, with black and grey feath­ers on the pos­te­rior. Breed­ing male Wil­son's phalaropes are mainly grey and black with a light cin­na­mon color on the nape. Breed­ing fe­males have more vi­brant col­or­ing than breed­ing males. The breed­ing fe­males have black feather pat­terns through their eyes that flow down the nape. The throat of a breed­ing fe­male is white and the nape is stained a vi­brant cin­na­mon color. Ju­ve­nile Wil­son's phalaropes have vi­brant col­ors sim­i­lar to the breed­ing fe­male ex­cept they lack the black feather pat­tern through the eyes. (Col­well, 1992; Wells, 2007)

• Other Physical Features
• endothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger
• sexes colored or patterned differently
• female more colorful

• Range mass

  38 to 128 g

  1.34 to 4.51 oz

• Range length

  22 to 24 cm

  8.66 to 9.45 in

• Range wingspan

  39 to 43 cm

  15.35 to 16.93 in

Re­pro­duc­tion

Fe­male Wil­son's phalaropes are polyan­drous, mean­ing they mate with many males. The fe­males at­tract the at­ten­tion of males with ag­gres­sive mo­tions such as whip­ping the head back and forth. Oc­ca­sion­ally, the fe­males will get into phys­i­cal al­ter­ca­tions with other fe­males when try­ing to claim and de­fend her mate. Once the fe­males has the at­ten­tion of a male, the fe­males would then pro­ceed in up­right pos­ture and stick out their neck feath­ers in courtship. (Col­well, 1986; Howe, 1975; Oring and Col­well, 1988)

• Mating System
• polyandrous

Male Wil­son's phalaropes breed once a year. Fe­male Wil­son's phalaropes breed mul­ti­ple times a year. Breed­ing oc­curs dur­ing the months of May through Au­gust. The fe­males will aban­don their clutch, in search of an­other male, while the orig­i­nal mate cares for the clutch. Each one of the fe­male's mates is re­spon­si­ble for a set of eggs. Clutch size is al­most al­ways four eggs. Oc­ca­sion­ally, a clutch will only be three, but this is rare. Once the fe­males lay their eggs, the male in­cu­bates them on av­er­age twenty-three days. The young are hatched with their eyes open, fully feath­ered, and able to find their own food. The young are in­de­pen­dent after an av­er­age of one day. The young are ca­pa­ble of breed­ing at one year old. (Dele­hanty and Oring, 1993; Oring and Col­well, 1988)

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

• Breeding interval

  Wilson's phalaropes breed at least once yearly

• Breeding season

  May through August

• Range eggs per season

  4 to 8

• Range time to hatching

  18 to 27 days

• Average fledging age

  30 days

• Average time to independence

  1 days

• Average age at sexual or reproductive maturity (female)

  1 years

• Average age at sexual or reproductive maturity (male)

  1 years

Fe­male Wil­son's phalaropes choose a nest­ing site and lays her eggs. The fe­male lays her eggs on the ground and then de­parts to seek out an­other mate, leav­ing the male to care for the off­spring. The male will build a nest around the eggs using the sur­round­ing veg­e­ta­tion as cam­ou­flage for the nest­ing site. Once the in­cu­ba­tion pe­riod ends the young will hatch, with their eyes open and fully feath­ered. The young are able to leave the nest within one day of hatch­ing, fully able to feed in­de­pen­dently. The male pro­vides pro­tec­tion from preda­tors by pre­form­ing a bro­ken wing act lur­ing the preda­tor away from the young. (Dele­hanty and Oring, 1993; Oring and Col­well, 1988)

• Parental Investment
• precocial
• male parental care
• pre-hatching/birth
  • provisioning
    • male
  • protecting
    • male
• pre-weaning/fledging
  • provisioning
    • male
  • protecting
    • male
• pre-independence
  • provisioning
    • male
  • protecting
    • male

Lifes­pan/Longevity

The av­er­age lifes­pan of Wil­son's phalaropes is ten years in the wild. This species is not found in cap­tiv­ity. Male and fe­male Wil­son's phalaropes have the same lifes­pan. This species of bird has a shorter lifes­pan than many other bird species. Drought and cold weather are lim­it­ing fac­tors for Wil­son's phalaropes. (Carey and Judge, 2000)

• Average lifespan
  Status: wild

  10 years

Be­hav­ior

Wil­son's phalaropes are a so­cial species. This species nests in loose colonies and dur­ing mi­gra­tion trav­els in large flocks. Wil­son's phalaropes mi­grate from north­west United States and Canada to the south­ern por­tion of South Amer­ica, which on av­er­age is 4,000 miles. Dur­ing spring months, Wil­son's phalaropes are lo­cated in the United States and Canada for breed­ing. Dur­ing win­ter months, Wil­son's phalaropes are lo­cated in South Amer­ica.

Wil­son's phalaropes are polyan­drous. The fe­male at­tracts the male with ag­gres­sive be­hav­ior and will oc­ca­sion­ally en­gage in phys­i­cal al­ter­ca­tions with other fe­males. Uniquely, male Wil­son's phalarope are wholly re­spon­si­ble for pro­tect­ing and car­ing for the young until hatch­ing. The male can deter preda­tors by act­ing as if he has a bro­ken wing.

This species is di­ur­nal. (An­drei, et al., 2006)

• Key Behaviors
• flies
• diurnal
• motile
• migratory
• colonial

• Average territory size

  0.5 m^2

Home Range

Wil­son's phalarope home range is their nest­ing area. The ter­ri­tory con­sist of the size of the nest and the im­me­di­ate area sur­round­ing the nest. The av­er­age home range is 0.5 square me­ters. Scolopaci­dae, com­monly known as sand­piper, have a sim­i­lar home range as the Wil­son's phalarope. (An­drei, et al., 2006; BirdLife In­ter­na­tional, 2012)

Com­mu­ni­ca­tion and Per­cep­tion

Dur­ing courtship, male and fe­male Wil­son's phalaropes make brief nasal calls to each other to keep in touch. Fe­males will also make a deep call when com­mu­ni­cat­ing over long dis­tances, how­ever, when this species is in close range to each other they will make a soft purring call. Dur­ing mi­gra­tion del­i­cate gur­gling is used to com­mu­ni­cate amongst each other. Most calls are geared to­ward short range com­mu­ni­ca­tion be­cause of the gre­gar­i­ous life style of Wil­son's phalarope.

Wil­son's phalarope use smell to find their way in the skies dur­ing mi­gra­tion. Sense of smell is also used to de­tect other Wil­son's phalarope as well as preda­tors. (Howe, 1975; Jehl, 1997)

• Communication Channels
• acoustic

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Wil­son's phalaropes for­age for food in a unique way. This species swims around in cir­cles cre­at­ing a whirlpool. This ag­i­tates any small aquatic in­ver­te­brate and algae from the sub­strate of a pond or lake and brings it to the sur­face. This species of bird also for­ages in the mud sur­round­ing the pond or lake for prey. Wil­son's phalaropes will probe their bill into the mud or stand still and snatch fly­ing in­sects out of the air. Wil­son's phalaropes rarely pur­sue prey while in flight. Wil­son's phalaropes eat op­por­tunis­ti­cally and their prey con­sist of mainly crus­taceans, aquatic in­sects, and aquatic lar­vae.

Oc­ca­sion­ally, on the mi­gra­tion path, Wil­son's phalarope eat so much that they dou­ble their body weight. Some­times the extra weight pre­vents them from fly­ing, which al­lows re­searchers to eas­ily catch them by hand. (Es­trella, et al., 2007; Roberts, 2013; Wells, 2007)

• Primary Diet
• carnivore
  • insectivore
  • eats non-insect arthropods
• herbivore
  • algivore

• Animal Foods
• insects
• aquatic crustaceans

Pre­da­tion

Wil­son's phalaropes have lightly col­ored feath­ers on their stom­achs and the ven­tral side of their wings that cam­ou­flages them from preda­tors on the ground while in flight. How­ever, the feath­ers on the dor­sal of this species are cin­na­mon and brown that blend with sur­round­ing veg­e­ta­tion cam­ou­flag­ing Wil­son's phalaropes from preda­tors while they are on the ground. A de­fense mech­a­nism com­monly ob­served in this species is the bro­ken wing act. The male will mimic a bro­ken wing to lure a preda­tor away from his young. Com­mon preda­tors are rac­coons Pro­cyon lotor, skunks Mephi­tis, garter snakes Thamnophis, and gulls Larus. All of these preda­tors prey on Wil­son's phalarope eggs as well as adult Wil­son's phalaropes. How­ever, gulls are the only preda­tor that will not prey on the adult Wil­son's phalarope. (Col­well, 1992; Jehl, 1997)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • raccoons (Procyon lotor)
  • skunks (Mephitis species)
  • garter snakes (Thamnophis species)
  • gulls (Larus species)

Ecosys­tem Roles

Wil­son's phalaropes aer­ate soil when search­ing for food by prob­ing the soil with their bill. Most of their food is lo­cated in the water. Wil­son's phalaropes are com­monly in­fected with en­dopar­a­sites such as Levin­se­niella howen­sis and ec­topar­a­sites such as bird lice. Wil­son's phalaropes are con­sid­ered a pri­mary con­sumer or a sec­ondary con­sumer be­cause it eats both algae and aquatic in­ver­te­brate. (Wells, 2007)

• Ecosystem Impact
• soil aeration

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Wil­son's phalaropes play a role in eco­tourism. Wil­son's phalaropes at­tract bird watch­ers for many rea­sons. The main rea­son bird watch­ers are at­tracted to Wil­son's phalaropes is their unique for­ag­ing be­hav­ior. This species spins around in cir­cles while swim­ming in the water which brings their food to the sur­face. (An­drei, et al., 2006; Es­trella, et al., 2007; Howe, 1975; Wells, 2007)

• Positive Impacts
• ecotourism

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse ef­fects of Wil­son's phalarope on hu­mans.

Con­ser­va­tion Sta­tus

Wil­son's phalaropes are not glob­ally threat­ened. They are listed on the IUCN Red List as a species of "Least Con­cern" due to their large ge­o­graphic range. Wil­son's phalarope are a pro­tected species ac­cord­ing to the United States Mi­gra­tory Bird Act which pro­tects Wil­son's phalarope from being killed, cap­tured, or sold. It has no spe­cial sta­tus on the Fed­eral List as well as on the Con­ven­tion on In­ter­na­tional Trade in En­dan­gered Species of Wild Fauna and Flora list.

Threats against Wil­son's phalaropes are degra­da­tion and loss of breed­ing habi­tat as the re­sult of drainage of wet­lands. Con­ser­va­tion mea­sures that are being taken are preser­va­tion of Wil­son's phalarope habi­tat by cre­at­ing con­ser­va­tion sites in the breed­ing ter­ri­tory of the United States and Canada as well as in the mi­gra­tory ter­ri­tory of Mex­ico. (BirdLife In­ter­na­tional, 2012; Col­well, 1986; Oring and Col­well, 1988)

• IUCN Red List

  Least Concern

• US Migratory Bird Act

  Protected

• US Federal List

  No special status

• CITES

  No special status

Con­trib­u­tors

Casey Wood (au­thor), Rad­ford Uni­ver­sity, Cari Mc­gre­gor (ed­i­tor), Rad­ford Uni­ver­sity, Zeb Pike (ed­i­tor), Rad­ford Uni­ver­sity, Karen Pow­ers (ed­i­tor), Rad­ford Uni­ver­sity, April Tin­gle (ed­i­tor), Rad­ford Uni­ver­sity, Jacob Vaught (ed­i­tor), Rad­ford Uni­ver­sity, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

An­drei, A., L. Smith, D. Haukos, J. Surles. 2006. Com­mu­nity com­po­si­tion and mi­gra­tion chronol­ogy of shore­birds using the saline lakes of the South­ern Great Plains, USA. Jour­nal of Field Or­nithol­ogy, 77/4: 372-383.

BirdLife In­ter­na­tional, 2012. "Stegano­pus tri­color" (On-line). The IUCN Red List of Threat­ened Species. Ac­cessed Jan­u­ary 27, 2016 at http://​dx.​doi.​org/​10.​2305/​IUCN.​UK.​2012-1.​RLTS.​T22693472A38830438.​en.

Bor­berg, J. 2005. A test for bias at­trib­ut­able to seabird avoid­ance of ships. Ma­rine Or­nithol­ogy, 33: 173-179.

Carey, J., D. Judge. 2000. Longevity Records: Life Spans of Mam­mals, Birds, Am­phib­ians, Rep­tiles, and Fish. Odense, Den­mark: Odense Uni­ver­sity Press.

Col­well, M. 1986. The first doc­u­mented case of polyandry for Wil­son's phalarope. The Auk, 103/3: 611.

Col­well, M. 1992. Wil­son's phalarope nest suc­cess is not in­flu­enced by veg­e­ta­tion con­ceal­ment. The Con­dor, 94/3: 767-772.

Dele­hanty, D., L. Oring. 1993. Ef­fect of clutch size on in­cu­ba­tion per­sis­tence in male Wil­son's phalaropes. The Auk, 110/3: 521-528.

Es­trella, S., J. Masero, A. Perez-Hur­tado. 2007. Small prey prof­itabil­ity: Field analy­sis of shore­birds' use of sur­face ten­sion to trans­port prey. The Auk, 124/4: 1244-1253.

Howe, M. 1975. So­cial in­ter­ac­tions in flocks of court­ing Wil­son's phalaropes. Con­dor, 77/1: 24.

Jehl, J. 1999. Pop­u­la­tion stud­ies of Wil­son's phalaropes at fall stag­ing areas, 1980-1997: A chal­lenge for mon­i­tor­ing. Wa­ter­birds, 22/1: 37-46.

Jehl, J. 1997. Fat loads and flight­less­ness in Wil­son's phalaropes. Con­dor, 99/2: 538.

Oring, L., M. Col­well. 1988. Sex ra­tios and in­tra­sex­ual com­pe­ti­tion for mates in a sex-role re­versed shore­bird, Wil­son's phalarope. Be­hav­ioral Ecol­ogy and So­cio­bi­ol­ogy, 22/3: 165-173.

Roberts, A. 2013. Avian diets in a saline ecosys­tem: Great Salt Lake, Utah, USA. Hu­man-Wildlife In­ter­ac­tions, 7/1: 158-168.

Roesler, I., S. Im­berti. 2015. Abun­dance and habi­tat use of nearc­tic shore­birds in the High­land Lakes of west­ern Santa Cruz Province, Ar­gen­tinean Patag­o­nia. Wa­ter­birds, 38/1: 86-91.

Sk­a­gen, S. 1994. Mi­grat­ing shore­birds and habi­tat dy­nam­ics at a prairie wet­land com­plex. The Wil­son Bul­letin, 106/1: 91-105.

Wells, J. 2007. Birder's Con­ser­va­tion Hand­book: 100 North Amer­i­can Birds at Risk. Prince­ton, NJ: Prince­ton Uni­ver­sity Press.