Castagneux Grèbe

The castagneux Grèbe ( Tachybaptus ruficollis ) is a bird of the family of the Podicipedidae . This bird is smallest of the family members of the Grèbe S, and also the grèbe of Europe to be only laid regularly twice a year.

Etymology

The word grèbe is used to indicate this kind of bird since at least the 16th century and would be of Savoyard origin.
Le word castagneux comes from Latin castanea , the Châtaigne, and would be a reference to the color châtain cheeks and throat of the bird in summer, or to the very round shape of its body.
With regard to the Latin name, Tachybaptus comes from the Greek tachus , rapid and baptizô , to plunge. The word ruficollis comes from Latin rufus , russet-red and parcel , the neck.

Description

Measurements

There is no sexual Dimorphisme at this species (except for some measurements, nozzle in particular), it is thus very difficult to distinguish male and female. It is a small water bird from 21 to 29 cm and a Envergure from 40 to 45 cm, for a varying weight from 100 to 275 G (on average 200 G). The other significant biometric characteristics are a folded wing from 93 to 104 mm, a nozzle from 18 to 21 mm (male) or from 16 to 18 mm (female) and a tarsus from 34 to 39 Misters.

General aspect

It has an appearance replette which had with its behind round-off, characteristic reinforced by the practice which has this grèbe to dishevel the feathers of its tail. Its aspect in “ball of sleeping bag” often gives the impression which it floats like a stopper. Like all the members of podicipédidés, it has lobed toes and its legs, greenish, are located very behind body, which confers to him good qualities of swimmer and plunger, but handicaps its movements on the ground. In fact, with share at the time of the nesting, this bird is seldom seen with ground.

Bridal plumage

In summer, it is very dark, almost black (in particular on the level of the chin), but present of the spots châtains on the throat, the cheeks and the sides of the neck. Its sides can sometimes be of a paler chestnut. The tail is maroon very clear. The lower part of the body is noirâtre more or less interfered with white and gray. This bird present at commissures of the black nozzle with white, thin and pointed point of the yellow marks in the form of apostrophe. The irises are brown red and the legs greenish gray with bluish.

The moult supplements is held August at December with the fall of the rémiges between August and October.

Plumage internuptial

In winter, the plumage is duller; the back takes a dirty color brown gray, the tail is almost white, just like the lower part of the body. The neck takes a color chestnut chechmate. The yellow marks of the nozzle grow blurred. One can then confuse it with the Grèbe with black neck ( Podiceps nigricollis ), but Grèbe castagneux is smaller, his neck is chamois (and not grisâtre), the shorter neck, the right nozzle and the cap more punt.

The partial moult is held February at June-July.

Aspect of the youthful ones

The chicks are covered with gray sleeping bag, their nozzle is yellow and they have the head, the neck and the back presenting of the yellowish stripes to russet-red.

The young people resemble to the adults in plumage internuptial but the cheeks and the sides of the dark brown neck are irregularly striped white. Their partial moult is held July at December.

Behavior

Flight

More adapted to the stroke than with the flight or rather than on takeoff since it must run on water 15 to 30 m by beating wings to take its rise, this bird is rather seldom observed in flight although it can fly very quickly and traverse long distances during its migrations. To the slightest warning, it plunges to reappear a little further or hides with talent in the high vegetation of banks. It often flies very low, sometimes in contact with water. It then holds its tended neck and its a little low legs. Contrary to the others grèbes, it presents in flight of white mirror, neither with front, nor with the back of the wings.

Migration

The populations living in Europe West and Africa of North are Sédentaire S. Those of Northern Europe migrate towards the south at the end of the summer. They spend the winter in the western part of Europe, mixing with the populations resident. The castagneux grèbes then form small groups which are interfered with other species wintering birds. In a more general way, only the populations nesting in the zones where water freezes in winter are migrating.

Food

Food mode

Contrary to the other species of grèbes which are primarily Piscivore S, the castagneux grèbe has a mode mainly Insectivore made up as well of larvae as of watery adults of insects (Libellule S, transitory S, pearl S, Phrygane S, Dytique S, Gyrin S) or not (Mouche S, Scarabée S). It consumes also small Crustacé S (aselles and Gammare S) and Mollusque S (limnées, physas, Planorbe S and Bithynie S) as well as Amphibien S (especially of the Têtard S, but also small Grenouille S or triton S) and fish whose size generally lies between 5 and 7 cm and does not exceed 11 cm (chubs, pins, young people of the kind Cyprinus like Carpe S, Gardon S, Vairon S, Bremen S, Bleak S, Pole S, Vandoise S, Rotengle S, épinoche S, etc). This food mode enables him to be established on too small water levels to contain large fish.

The stomach of castagneux Grèbe contains sometimes plants, probably introduced by error. It also generally contains some feathers, but does not need to introduce of it large quantity like the grèbes more strictly piscivorous.

Food behavior

Il captures its preys while plunging during 10 to 25 seconds (maximum 33 S, only 8 divings ranging between 25 and 33 S out of 240 timed) up to 1 even 2 m of depth (maximum 6,3 m). It can also swim the immersed neck and the head and catch by pricking them of the nozzle of the preys posed on the surface or on floating plants. Contrary to the Grèbe with black neck, castagneux Grèbe makes surface before swallowing its preys.

It is rather frequently nourished in partnership with other species (Malagasy Grèbe and reddish Grèbe in Madagascar) or while benefitting from displacements of preys caused by other species feeding. Such commensaux behaviors were observed in Europe, in particular in France with respect to the Cygne tuber and of the Canard chipeau, and in Madagascar with respect to Erismature with white back, of the widowed Dendrocygne, Anserelle dwarf and Duck with red nozzle.

Reproduction

Formation of the couples

The couples are formed in autumn and winter within the groups. Thus, they are generally established at the time of the arrival of the birds on their sites of nesting.

Territory

The territory is quickly delimited by the couple. It is used for the parades, the copulation, the food, the installation of the nest and the breeding of the young people.

Bridal parade

The couples are apparently Monogame S. At the time of the bridal parade, the male roughcasts its plumage, strikes the water of its nozzle, plunges and splashes around him with its legs, sometimes imitated by its partner. Cases of hybridization with reddish Grèbe and Malagasy Grèbe were also noted.

Longevity

The longevity of this bird is estimated at 10 or 15 years.

Wintering

The winter gatherings are attended year dormitories by year between October and March. The birds separately join them or in small groups. The known maximum is of 700 birds on a Champagne lake.

Voice

The presence of castagneux Grèbe is often revealed in bridal period by its trilles sound neighing emitted a little at the time of the season of Nidification, and by its calls (bii-iip). This bird produces also a little metal chirps and noises (ûit-ûit) (to listen to its cry on this page).
Il sings especially March at the end of July, for the period of reproduction. Quieter in winter, it can however be heard during the sunny beautiful days.

World and European distribution

Subspecies and world distribution

This species of grèbe has eight subspecies distributed as follows:

Tachybaptus ruficollis capensis (Salvadori, 1884): Africa, South of the the Sahara, Madagascar, of the the Caucasus to the Burma while passing by the India and the Sri Lanka;

Tachybaptus ruficollis collaris (Mayr, 1945): New Guinea, the Solomon Islands;

Tachybaptus ruficollis cotabato (Rand, 1948): south-east of the Filipino ;

Tachybaptus ruficollis philippensis (Bonnaterre, 1791): north of the Filipino ;

Tachybaptus ruficollis iraquensis (Ticehurst, 1923): Iraq, Iran;

Tachybaptus ruficollis poggei (Reichenow, 1902): Asian south-east and north-eastern , Hainan, Taiwan, Japan, south of the Islands Kouriles (also called Tachybaptus ruficollis kunikyonis );

Tachybaptus ruficollis ruficollis (Pallas, 1764): Europe until the the Ural, the African North-West ;

Tachybaptus ruficollis tricolor (G.R. Gray, 1861): Indonesia, New Guinea, Java, Timor (also called Tachybaptus ruficollis vulcanorum ).

The IUCN estimates that the world population of castagneux Grèbe counts from 470.000 to 2,6 million individuals.

European distribution

Castagneux Grèbe niche in 35 European countries with the manpower estimated at 81.000 couples including 2.500 to 3.000 in France (where 5.000 individuals would be present in winter), 650 to 800 couples in Belgium and 3.700 couples in Switzerland (between 1970 and 1980). However, this species strongly decreased on Léman in winter with more than 6.000 individuals about 1967 and only 2.300 in 1987. 1.500 couples reproduce in Russia and 15.000 in Turkey.

Habitat

Castagneux Grèbe will settle on any lake, pond, pond or marsh having a rather dense vegetation on its banks. Moreover, it can reproduce on the ponds of the public parks of big cities like London and Amsterdam, or in gravel pits or broad ditches flooded, tanks, even in sheltered coastal bays or Estuaire S.

It niche primarily in the wetlands of the plains and the plates but also, locally, on average mountain (up to 1300 m in Austria and 1710 m in Switzerland).

In summer, he prefers the water levels presenting a sufficiently high vegetation to dissimulate his nest, but in winter, one can find it in more released places. Wintering in great number the interstitial waters of the lakes and the rivers attend. They are also on water Saumâtre S or salted estuaries, gulfs, lagoons and ports. The urban water levels are also used. Because of its food mode less piscivorous than that of the others grèbes, it is rather frequently on water levels of very small size.

Statute and safeguarding

Discrete bird, castagneux Grèbe is easily disturbed by the human presence. In addition to the human pressure, the principal threats for this bird are the draining of the marshes, the concreting of banks, the excessive clearing out of the rivers and the urbanization, which limit its sites of nesting. It can also be reached by the water pollution via its food. In the Mediterranean region, it can be victim of hunting for the wildfowl.

In spite of that, the species is for the moment commune. IUCN estimates dimensions of its surface of distribution at 10 its population and km ² million, between: 470000 and 2,6 million individuals. This organization thus classified the species in the " category; concern mineure".

In the same way, the Accord on the conservation of the migrating water birds of Africa-Eurasia classified the species in the C1 category, i.e. like a population not threatened, counting more than 100.000 individuals, but likely to profit, on the whole, of an international cooperation.

BirdLife International considers its population European at more: 99000 couples, with a stable evolution or in rise in the majority of the countries (except in Turkey), and places it in the category of the not threatened birds. This species is also considered since 1994 as made safe by the European Agence for the environment (AEE), but was declared vulnerable in Switzerland and in the Netherlands.

Although absent from the list of the European commission of the birds most threatened of Europe, this grèbe is protected all the same by the Convention from Bern (2002).

Philately

This bird was represented on stamps emitted by several countries: Island of Man in 1997, Japan in 1991, Bailliage of Jersey in 1999, Zaire in 1982, the Dominique in 1998 and the islands Maldives in 1985.

Bonds and references

Photographs and Video

Flickr Gallery on swimming and plunging Avibase
Photo Adult Calphotos
in bridal plumage (ssp ruficollis), Catalonia, Spain
an adult with the nest with his chicks (ssp ruficollis), plunging Ligneuville, Belgium
Adult and nourishing a chick (ssp ruficollis), Ligneuville, Belgium
Gallery aves on the grèbe castagneux
Photographs of castagneux Grèbe on African Bird Club

Random links: