Anas bahamensis

Geographic Range

White-cheeked pintails, Anas bahamensis , have a range that includes Central and South America. Their northern range includes the southern coast of Florida, the Bahamas, Puerto Rico, Haiti, and Cuba. The range is sporadical along the coast of South America including the western coasts of Peru, Chile, and Ecuador (including the Galapagos Islands). The northern coast of South America includes populations in Guyana, Venezuela, and Colombia. There are two disjunct populations along the eastern coast of Brazil. White-cheeked pintails also have an inland range that is as far north as Bolivia and as far south as Argentina. One individual was found in 1929 on a Wisconsin lake.

White-cheeked pintails have three subspecies that are separated geographically, Anas bahamensis bahamensis , Anas bahamensis rubrirostris , and Anas bahamensis galapagensis . Lesser white-cheeked pintails, Anas bahamensis bahamensis , are located primarily in northern South America and the southern coast of Florida. Located in the southern range of South America are the greater white-cheeked pintails, Anas bahamensis rubrirostris . Lastly, the Galapagos pintails, Anas bahamensis galapagensis , are limited in distribution to the Galapagos Islands.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

White-cheeked pintails are most commonly found in saltwater habitats, such as lagoons, bay shores, tidal regions and mangroves. Although it is not as frequent, they can live in inland freshwater ponds and marshes that are shallow and calm. Brackish water is also another option when finding their acquired environment. While nesting, they can be found in areas that are not highly disturbed with dense grass, forbs, and sedges. It is also common for them to have their nest and raise young in an area where disturbance is minimized. When greater white-cheeked pintails are not having young they typically move away from the breeding site. Elevation is not reported for this species.

• Habitat Regions
• saltwater or marine saltwater or marine
• freshwater freshwater

• Aquatic Biomes
• lakes and ponds
• coastal coastal
• brackish water brackish water

• Wetlands
• marsh marsh

Physical Description

White-cheeked pintails are identified by the white spot located on their cheeks. These dabbling ducks have a grey-blue bill, with a red spot at the base. These dabbling ducks have brown feathers, and black spots on their chest, breast, and sides. The side of their head and throat are white. They show a line of demarcation between their brown crown and white area. They have grey legs and red to red-brown eyes. Compared to males, females are smaller, have a shorter tail length, and are not as brightly colored.

In comparing subspecies, greater white-cheeked pintails (total length 44 to 51cm) are brighter and larger than lesser white-cheeked pintails (total length 41 to 48 cm). Galapagos pintails (total length 38 to 45 cm) are generally the smallest and lack the major line of demarcation between their brown crown and white area. Galapagos pintails have a wingspan of 55 to 62 cm, while lesser white-cheeked pintails' wingspanis 58-65 cm, and greater white-cheeked pintails' wingspan is 60 to 68 cm. For all subspecies, females are larger, weighing an average of 569 grams, while males average 503 grams.

Ducklings are brighter in color, have a distinguishing black line from their eye to the back of their neck, and have a pink spot at the base of their bill. At birth, ducklings weigh around 34g.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger
• male more colorful

Reproduction

White-cheeked pintails typically form a monogamous mating pair and stay together during the season. Forced extra-pair copulations were demonstrated and polygynous relationships have been noted. Sorensen (1992) reports cases of polygynandry where females will switch males due to being left alone for some periods of time. She reports mate-switching up to 27% of the pairs she studied. The amount of spring and winter rainfall can affect mating periods. If there's irregular rainfall, then the female breeding season is affected, and that gives males the opportunity to mate with another female.

Females show interest in males by a stiff-necked motion, and males will show the back of their necks in return. Copulation is then proceeded by head pumping from both the male and female. Vocalization is also part of the mating ritual.

• Mating System
• monogamous monogamous
• polygynous polygynous
• polygynandrous (promiscuous) polygynandrous (promiscuous)

White-cheeked pintail females will lay eggs outside of the males' territory. These ducks have 5 to 12 eggs per season/per year, as the breeding season is year-round. Females will incubate for 21 to 22 hours a day, then spend the other 2 to 3 hours visiting the males. Although incubation periods have not been published for the white-cheeked pintails, duration for the related northern pintail Anas acuta is listed as 22 to 24 days. It is suspected that white-cheeked pintails have similar incubation times. When hatched, females lead their young to a protective water environment (e.g., limited number of predators), where they will not be disturbed. White-cheeked pintails' fledge in 45 to 60 days.

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

White-cheeked pintail males show no involvement in providing care for the ducklings. Females, on the other hand, protect their young. They guard the young, attend to their helpless calls, and try to defend the pond from any potential predators. Males spend less time in the alert position than females, and spend less time protecting the young.

• Parental Investment
• female parental care female parental care
• pre-fertilization
  • protecting
    • female
• pre-hatching/birth
  • protecting
    • female
• pre-independence
  • protecting
    • female

Lifespan/Longevity

The maximum lifespan recorded in the wild for white-cheeked pintails was 6 years, 3 months. This record was for a duck that was shot, and therefore, its natural longevity is still unknown. There is no information on lifespan in captivity because pintails are not typically kept in captivity.

Behavior

White-cheeked pintail diurnal behaviors include foraging, avoiding predation, and looking for mates. These ducks are also one of the few in the Anas genus that are sedentary (non-migratory). It is common for white-cheeked pintails to demonstrate swimming and sticking their heads under water (dabbling) to forage. Communication is another example of behavior, such as quacking, visual displays, etc. Pintails travel in pairs or small flocks. They become very tame, and the free-living ducks have adapted to living on the shore line begging at the restaurants located at the border.

Female pintails differ from males by a select few behavior patterns. They both behave in a protective way, but females show protectiveness over young while males are protective over their habitat throughout breeding season.

• Key Behaviors
• flies
• natatorial natatorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• social social

Home Range

White-cheeked pintails move very little daily, and are affected by food supplies. Although home range has not been reported, Rivera-Milán and Bonilla-Martínez (2007) estimated density of white-cheeked pintails as 2.33 individuals per hectare. Sorenson (1992) reported 5.8 birds per hectare (range 2.7-10.6).

Communication and Perception

White-cheeked pintails employ their vision when finding the appropriate source of food. As dabblers, they find their food, submerged plants, by sticking their heads under water. When communicating with others they use vocalization. Males' calls consist of whistles, while females produce a low quack sound of four to eight syllables. High-low quack sounds are articulated when females are separated from their mates. These ducks vocalize when performing mating rituals. Ducklings make peeping sounds

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

White-cheeked pintails primarily feed on submerged plants, and are well known as dabblers. Their proper food supply is found within salt lakes, ponds, lagoons, and salt ponds. White-cheeked pintails commonly skim across the surface, then stick their heads under water to reach plants that are submerged. Along side of the plants located in the sediment, algae and widgeon grass Ruppia are part of their diet. Many of these ducks will group together to eat the nutritious widgeon grass. Ducklings feed on grass seeds and aquatic invertebrates. The daytime is usually the time for feeding.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • granivore granivore
  • lignivore
  • algivore

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• algae

Predation

White-cheeked pintails primarily are faced with predation by humans, Homo sapiens , who illegally hunt them. There are many potential nest predators. They include mammals such as rats Rattus and domestic dogs Canis lupus familiaris . Bird nest predators include laughing gulls Larus atricilla , yellow-crowned night-herons Nyctanassa violacea , and smooth-billed anis Crotophaga ani . Another known predator is a white land crab, Cardisoma guanhumi . López-Flores et al. (2003) report one case of an American bullfrog Lithobates catesbeianus consuming a duckling. Because they lack anti-predator actions, their eggs and young are often consumed.

Ecosystem Roles

Muniz-Pereira and Amato (1993) examined 18 white-cheeked pintails in Brazil, and 22.2% were infected by the eyefluke, Philophthalmus gralli . Also in Brazil, Amato and Muniz-Periera (1995) showed white-cheeked pintails carrying another parasite, a digenean trematoda Notocotylus breviserialis . The prevalence of this parasite in these ducks was 5.56%.

Economic Importance for Humans: Positive

White-cheeked pintails benefit the human population by being hunted by humans. Humans illegally hunt these dabbling ducks, although it has not been reported whether these ducks are used as food or for their feathers.

Economic Importance for Humans: Negative

There are no negative economic impacts of white-cheeked pintails on humans.

Conservation Status

The IUCN Red List page white-cheeked pintails as a species of "Least Concern," although their population is declining. In Puerto Rico and the Virgin Islands, white-cheeked pintails are listed as a species on conservation concern. The Migratory Bird Treaty Act lists them as protected, and states that it is illegal to sell these birds without a permit. The State of Michigan list, CITES, and the US Federal list white-cheeked pintails as "no special status." Illegal hunting by humans is a major threat, and this is being restricted unless one has a permit.

Additional Links

Encyclopedia of Life

Contributors

Jacqueline Cain (author), Radford University, Alex Atwood (editor), Radford University, Karen Powers (editor), Radford University, Joshua Turner (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

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