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Phalaropus tricolorWilson's phalarope

By Casey Wood

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)

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)

  • Aquatic Biomes
  • lakes and ponds
  • temporary pools
  • 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)

  • 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)

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)

  • 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)

  • 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)

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)

  • 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

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)

Commensal/Parasitic Species

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)

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)

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.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

freshwater

mainly lives in water that is not salty.

herbivore

An animal that eats mainly plants or parts of plants.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

marsh

marshes are wetland areas often dominated by grasses and reeds.

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

soil aeration

digs and breaks up soil so air and water can get in

tactile

uses touch to communicate

visual

uses sight to communicate

young precocial

young are relatively well-developed when born

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.

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