American Avocet

American Avocet

Blue shanks

Kingdom
Phylum
Class
SPECIES
Recurvirostra americana
Population size
450,000
Life Span
9-15 yrs
TOP SPEED
40 km/h
WEIGHT
275-350 g
LENGTH
43-47 cm
WINGSPAN
72 cm

Flocks of elegant American avocets are found around tidal flats and lake shores, especially in wide open spaces in the west, wading in the shallows. These birds often feed leaning forward, the tip of their bill slightly open in the water, filtering tiny items of food that are just below the surface. A flock will sometimes feed this way together, walking forward as they swing their heads from side to side in rhythm.

Distibution

American avocets breed in western North America and on the Atlantic Coast. They winter in coastal California, Florida, southern Texas, Louisiana and Guatemala. They occur in Canada, Mexico, Puerto Rico, Costa Rica, Cuba and other countries in Central America and northern part of South America. This species is common in fresh and salt water that is shallow, in ponds, and lakeshores. They are also found in freshwater marshes, mudflats and wetlands, and islands (coastal or bay), and tidal flats.

Climate zones

Habits and Lifestyle

American avocets are a migratory species that are colonial nesters and form social groups. Outside the breeding season, these birds may gather in flocks numbering several hundred, and feed within dense groups. Their activity patterns are crepuscular. They feed by probing, as they swing their long bill from side to side in mud and shallow water, foraging for aquatic insects. Sometimes they feed in deep water, by using the “tip up” method and swimming. These birds are territorial and engage in displays to establish a territory and defend it. Two pairs, or a pair and a single bird stand in front of one another in a circle. They stretch their bills out towards each other, and, as a predator approaches, they will walk towards it with their teetering gait and outstretched wings. They may also crouch on the ground, then move, and crouch again elsewhere. They also dive bomb if intruders appear and they may become very aggressive.

Diet and Nutrition

The American avocet is omnivore and eats aquatic animals, including insects, shrimps and other crustaceans, as well as aquatic plants and seeds on the surface of marshes and ponds.

Mating Habits

MATING BEHAVIOR
REPRODUCTION SEASON
April-June
INCUBATION PERIOD
22-24 days
INDEPENDENT AGE
28-35 days
BABY NAME
chick
BABY CARRYING
3-4 eggs

American avocets are monogamous and pairs nest in loose colonies. Pairs engage in elaborate courtship displays involving various postures of crouching and bowing, both in and out of the water, dancing with wings outspread and swaying side to side. Breeding takes place between April and June. The pair builds their nest in a wet area on the ground. If water rises, they build up the nest, adding sticks, feathers and weeds, to make sure the eggs are above water level. 3 to 4 eggs are laid, olive-colored with dark spots. Incubation is for around 22 to 24 days, and is done by both parents. The chicks are precocial when they hatch, and several hours later are very active. They can both feed themselves and swim. They fledge at around 28 to 35 days old.

Population

Population threats

The main threats to this species today are habitat degradation and loss. Their nests are vulnerable to trampling by cattle, pollution and flooding. Furthermore, the small size of the breeding population puts these birds under threat from random environmental and climate changes.

Population number

According to the What Bird resource, the total number of the American avocet is around 450,000 birds. Currently this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today remain stable.

Ecological niche

American avocets have an important role in their ecosystem; due to their food habits they probably control crustacean and insect populations, and they also are an important source of food for their predators. Furthermore, they influence the plants and seeds that they eat.

Fun Facts for Kids

  • The American avocet has the popular name “blue shanks” because of the bluish-gray color of its legs and feet.
  • As a reaction to predators, these birds sometimes make a series of calls that gradually change in pitch, imitating the Doppler effect and therefore making their approach seem faster than in reality.
  • An American avocet may lay in another bird’s nest her one to four eggs, which are then incubated by this substitute mother.
  • Avocets sometimes incubate mixed clutches of eggs that are their own along with those of black-necked stilts or common terns. They rear these hatchlings as if they are their own.
  • The tip of the American avocet’s long upcurved bill, like most shorebirds, is very sensitive to touch, which helps with detecting invertebrates in the mud.

References

1. American Avocet Wikipedia article - https://en.wikipedia.org/wiki/American_avocet
2. American Avocet on The IUCN Red List site - http://www.iucnredlist.org/details/22693717/0

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