Rattle rail

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Rattle rail
R. l. saturatus, a subspecies of the rattle rail widespread on the coast of the Gulf of Mexico (lithograph by John Gerrard Keulemans)

R. l. saturatus , a subspecies of the rattle rail widespread on the coast of the Gulf of Mexico (lithograph by John Gerrard Keulemans )

Systematics
Class : Birds (aves)
Order : Crane birds (Gruiformes)
Family : Rallen (Rallidae)
Genre : Rallus
Type : Rattle rail
Scientific name
Rallus longirostris
Boddaert , 1783

The rattling Rail ( Rallus longirostris ) is a medium-sized ground bird from the family of Rails . Collapsible halls live by the water, primarily in salt and brackish water marshes, in the tropics and subtropics but also in fresh water marshes. Their distribution extends from California through Central America and the Caribbean to South America. The Dutch doctor and naturalist Pieter Boddaert first described the rattle rail in 1783.

Appearance and voice

Collapsible locks are between 31 and 40 centimeters tall. Male specimens weigh between 300 and 350 grams and females between 248 and 301 grams. In its plumage, the longirostris subspecies differs from subspecies such as obsoletus , levipes and scotti , whose feathers are either brown or olive, by being lighter in color . The juvenile dress is darker in color (in some subspecies up to black), with white feathers in the belly area. The different subspecies can be distinguished primarily on the basis of their size and the color of their plumage, for example the extent to which the reins and cheeks are gray.

The voice of the rattle rail resembles that of the king rail ( Rallus elegans ). The vocal repertoire ranges from slowly performed rasping or grunting sounds to series of fast "kek" sounds.

distribution and habitat

The distribution of the 21 subspecies of the rattle rail extends from California through Central America and the Caribbean to South America:

  • R. l. obsoletus - Central California, especially in the San Francisco Bay area
  • R. l. levipes - Central California coast to northern Baja California
  • R. l. yumanensis - Southeastern California, Southern Arizona, and northwestern Mexico
  • R. l. beldingi - Southern Baja California
  • R. l. crepitans - South coast of Connecticut to northeastern North Carolina
  • R. l. waynei - coast of southeast North Carolina to eastern Florida
  • R. l. saturatus - Gulf coast from southwest Alabama to northeast Mexico ( Tamaulipas ).
  • R. l. pallidus - Yucatán coast (southeastern Mexico)
  • R. l. grossi - Quintana Roo (southeastern Mexico)
  • R. l. belizensis - Ycacos Lagoon, Belize
  • R. l. scotti - Florida coast
  • R. l. insularum - Florida Keys
  • R. l. coryi - Bahamas
  • R. l. leucophaeus - Isla de la Juventud (near Cuba)
  • R. l. caribaeus - Cuba to Puerto Rico and eastern Lesser Antilles to Antigua, also Guadeloupe
  • R. l. cypereti - coast from southwest Colombia ( Nariño ) via Ecuador to northwestern Peru ( Tumbes )
  • R. l. phelpsi - northeast Colombia to northwest Venezuela
  • R. l. margaritae - Isla Margarita (Venezuela).
  • R. l. pelodramus - Trinidad
  • R. l. longirostris - Coasts of Guyana, Suriname and French Guiana
  • R. l. crassirostris - coast of Brazil from the mouth of the Amazon to Santa Catarina

Collapsible halls live by the water, mainly in salt and brackish water marshes; in California preferentially in swampy areas, which are overgrown with certain kinds of silt grasses ( Spartina foliosa ) or springs . In addition, they can be found in mangroves and in tropical and subtropical freshwater marshes (especially in the lower valley of the Colorado River ).

Reproduction

Clutch of subspecies R. l. levipes

The reproduction of the animals takes place in the USA mainly in the months April to June; in Mexico in March; in Trinidad from May to June; in Venezuela in April. Rushes, sedge and material from marsh plants are used as nesting material for the nests hidden in dense vegetation. Collapsible cages are monogamous and tied to one partner for the breeding season.

2–16 eggs are laid. Data from the Western Foundation of Vertebrate Zoology and the Laboratory of Ornithology at Cornell University provide information on the differences between individual subspecies with regard to the size of the respective clutch:

subspecies Medium
clutch size 		Span
R. l. obsolete 8.3 4-14
R. l. levipes 7.3 5-11
R. l. yumanensis 6.7 3-7
R. l. beldingi 6.4 5-8
R. l. crepitans 9.2 4-16
R. l. waynei 9.4 5-15
R. l. scotti 7.3 2-11
R. l. insularum 6.5 6-7
R. l. saturatus 9.5 7-14
R. l. caribaeus 6.5 6-7

The young hatch after an incubation period of 18 to 29 days. When they flee the nest , the young leave the nest immediately after hatching, but usually return to the nest at night in the following days. The young animals are fed by their parents for five to six weeks. After seven to eight weeks, the plumage is fully developed and after 10 weeks the young are fledged.

Food and subsistence

A rattle rail in Florida foraging for food

Rattling barrels feed on both vegetable and animal sources. As opportunists, they prefer whatever food is available to them. Their animal diet includes mollusks, leeches, crustaceans, aquatic insects, grasshoppers, spiders, small fish, tadpoles, frogs, and mice. The vegetable diet of rattle rallies included seeds, berries, green parts of plants and tubers. In the winter months, the food consists more of plant components than animal ones.

To eat, rattle paws poke their long beaks in the muddy ground for food; sometimes they also dive for food. The foraging mostly takes place at low tide, also in the morning and early evening.

Predators and causes of mortality

Although there are no studies on this subject to date, it is assumed that a very high number of rattle chicks fall victim to predators. Of fish crows ( Corvus ossifragus ) is known to eat the eggs of the rattling Rail and the Laughing Gull ( Leucophaeus atricilla ) we know that it pecks eggs and eats chicks. While the raccoon is known as the most common nest predator in Georgia , the eggs of the rattle rail in California are eaten by the brown rat ( Rattus norvegicus ) and the originally non-native red fox ( Vulpes vulpes ).

As predators of adult animals include Great Blue Heron ( Ardea herodias ), bald eagle ( Haliaeetus leucocephalus ), hen harriers ( Circus cyaneus ), desert buzzards ( Parabuteo unicinctus ) Rotschulterbussarde ( Buteo lineatus ) Rotschwanzbussarde ( Buteo jamaicensis ), King buzzards ( Buteo regalis ), white-tailed buzzards ( Buteo albicaudatus ), peregrine ( Falco peregrinus ), prairie Hawk ( Falco mexicanus ), barn owls ( Tyto alba ), horned owl ( Bubo virginianus ), eared owls ( Asio Stain ) and ravens ( Corvus Corax ) is known. Among the mammals, raccoons and red foxes (in the region around the Bay of San Francisco ) occur as predators of adult rattle reels. But minks ( Neovison vison ), coyotes ( Canis latrans ), Südopossums ( Didelphis marsupialis ), as well as dogs and cats are known as predators of adult animals.

Other causes of mortality are ribbed bivalve molluscs ( Geukensia demissa ) or other types of bivalve molluscs that close around the toes or beak of ratchet claws and either drown or starve the animals. In addition, storms cause losses during the nesting season.

Persistence and Threat

The IUCN sees the stocks of the rattle rail currently not endangered (LC = least concern). In 2012, the total number of collapsible cages was roughly estimated at 3,500–3,700 individuals, including 2,300–2,500 adults.

In the US, three subspecies are threatened by habitat destruction by humans. In 1990, 190 breeding pairs of the subspecies levipes were counted in the USA and around 240 breeding pairs in Mexico. In 1991 around 400 breeding pairs of the subspecies obsoletus were counted; Especially in the area around the Bay of San Francisco , the habitats of the rattle rail are under constant pressure from urbanization . In 1992 , around 2,000 animals of the subspecies yumanensis were counted in the Colorado River delta . In the habitats on the coast of the Gulf of Mexico , the stocks are also under additional pressure from hunting.

literature

Web links

Commons : Rattle Rail ( Rallus longirostris )  - Collection of images, videos and audio files

Individual evidence

  1. ↑ For a sound sample cf. Bird singing in mangrove in Atlantic Forest ecosystem region , via: The Internet Bird Collection - Clapper Rail (Rallus longirostris), last accessed July 12, 2014.
  2. ↑ For a sound sample cf. A rail singing in its habitat (mangrove) , via: The Internet Bird Collection - Clapper Rail (Rallus longirostris), last accessed July 12, 2014.
  3. ↑ a b c For this and the following cf. B. Taylor, Clapper Rail (Rallus longirostris) , in: Handbook of the Birds of the World Alive, ed. by J. del Hoyo / A. Elliott / J. Sargatal / DA Christie / E. de Juana, Barcelona 2013 (paid access; last accessed on July 12, 2014).
  4. ↑ The data in the table from: Scott A. Rush / Karen F. Gaines / William R. Eddleman / Courtney J. Conway: Clapper Rail (Rallus longirostris) , section "Demography and Populations", in: The Birds of North America Online, ed. by A. Poole, Ithaca 2012 (access with costs; last accessed on July 13, 2014).
  5. ↑ On this and the following cf. Rush / Gaines / Eddleman / Conway, Clapper Rail (Rallus longirostris) , “Behavior” section, in: The Birds of North America Online (paid access; last accessed July 20, 2014).
  6. ↑ On this and the following cf. Rush / Gaines / Eddleman / Conway, Clapper Rail (Rallus longirostris) , section “Demography and Populations”, in: The Birds of North America Online (paid access; last accessed July 20, 2014).
  7. ↑ a b Rallus longirostris , in: The IUCN List of Threatened Species, 2014.1 (last accessed July 20, 2014).