great grebe or great grebe (P. cristatus) is a bird from the grebe order. It is found in lakes and ponds throughout almost all of Eurasia. A tricolor bird the size of a duck. Despite its offensive name, derived from the tasteless meat with a strong fetid odor, this Great Grebe is a very unusual bird that builds amazing nests. The most numerous populations are located on the territory of Russia.
Origin of the species and description
Toadstools — this is a radically different group of birds in terms of their anatomy. At first, they were thought to be related to the loons, which are also walking waterfowl, and both families were once classified as one order. In the 1930s, this was identified as an example of convergent evolution driven by the selective opportunities faced by unrelated bird species living the same lifestyle. Loons and grebes are now classified as separate orders Podicipediformes and Gaviiformes.
Interesting fact: Molecular studies and sequence analysis do not properly resolve the relationships of grebes with other species. However, studies show that these birds create an ancient evolutionary line, either subjected to selective pressure to the molecular level, unrelated to loons.
The most comprehensive study of avian phylogenoms, published in 2014, demonstrated that grebes and flamingos are members of Columbea, a branch that also includes doves, grouse, and mesites. Recent molecular studies have identified a link to flamingos. They have at least eleven morphological features not found in other birds. Many of these characteristics have been previously identified in flamingos but not in grebes. Fossil specimens from the Ice Age may be considered evolutionarily intermediate between flamingos and grebes.
True grebes are found in fossils in the late Oligocene or Miocene. While there are several prehistoric genera that are now completely extinct. Thiornis (Spain) and Pliolymbus (USA, Mexico) date back to a time when almost all existing genera already existed. Since grebes were evolutionarily isolated, they began to be found in the fossils of the Northern Hemisphere, but they probably originated in the Southern Hemisphere.
Appearance and features
Great Grebe — the largest grebes in Europe. The plumage on the back and sides is mottled brown. The back of the neck is dark brown, while the front of the neck and underside are white. They have long necks and reddish-orange feathers with black tips on their heads. These feathers are present only during the breeding season, they begin to develop in winter and are fully developed by spring. The birds also have erectile black crests on the top of their heads which are present all year round. Great Grebes have short tails and legs set far back for efficient swimming. Young birds have black stripes on their cheeks.
Toadstools have a length of 46 to 52 cm, a wingspan of 59 to 73 cm. They weigh from 800 to 1400 g. Sexual demorphism is only slightly pronounced. Males are slightly larger and have a slightly wider collar and a longer hood in their dress. The beak is red in all attire with a brown crest and a bright top. The iris is red with a light orange ring enveloping the pupil. Legs and floating lobes are greenish gray.
Recently hatched grebe chicks have a short and dense down robe. The head and neck are painted in black and white color lines arranged in longitudinal directions. Brown spots of various sizes appear on the white throat. The back and sides of the body are initially less contrasting, brownish-white and black-brown striped. The lower part of the body and the chest are white.
Where does the great grebe live?
Great Crested Grebes — residents of Western and Eastern Europe, Great Britain and Ireland, parts of Southern and Eastern Africa, Australia and New Zealand. Tribal populations are found in Eastern Europe, southern Russia and Mongolia. After migration, wintering populations can be found in the coastal waters of Europe, southern Africa and Australia, as well as in water bodies throughout southern Asia.
Great Grebe breeds in vegetated areas of freshwater lakes. Subspecies P. s. Cristatus is found throughout Europe and Asia. It resides in the milder west of its range, but migrates from colder to warmer regions. It winters in freshwater lakes and reservoirs or on the coast. African subspecies P. c. infuscatus and the Australasian subspecies P. c. australis are mainly sedentary.
Fun Fact: Grebes can be found in a variety of aquatic environments, including lakes, artificial ponds, gently flowing rivers, swamps, bays, and lagoons. Breeding grounds consist of shallow open bodies of fresh or brackish water. There should also be vegetation on the shore and in the water to provide suitable nesting sites.
In winter, individuals of some populations migrate to water bodies located in a temperate climate. Lake Geneva, Lake Constance and Lake Neuchâtel are among the European lakes where many Great Grebes live during the winter months. They also winter on the West European Atlantic coast, where they arrive in large numbers in October and November and stay until late February or early March.
Other important wintering areas are the Caspian Sea, the Black Sea and some inland waters in Central Asia . In East Asia, wintering in southeastern and southern China, Taiwan, Japan and India. Here they also mostly remain in the coastal zone.
What does a grebe eat?
Grebes catch their prey by diving under the surface of the water. They prey the most at dawn and dusk, perhaps because that’s when their prey rises closer to the surface. This makes it easier to visually locate the fish and also reduces the diving distance.
The diet of the Great Crested Grebes consists mainly of:
- large fish;
- spiders and aquatic insects;
- small crustaceans;
- adult and larval frogs;
- invertebrate larvae.
The maximum size of fish that grebes eat is 25 cm. Their typical fish prey in fresh water includes: topfish, carp, roach, white fish, gobies, pike perch, pike. More detailed studies have shown that there are significant differences in the nutritional composition between individual groups of the species.
The daily requirement for food is about 200 grams. The chicks first feed on insects. In wintering areas, grebes feed only on fish. In salty waters gobies, herring, stickleback, cod and carp are found, which make up the bulk of their prey. Grebes eat large fish on the surface of the water, swallowing the head first. Small individuals are eaten underwater. They dive for at least 45 seconds while hunting and swim underwater at a distance of 2-4 m. The maximum proven diving distance is 40 meters.
Grebes are not territorial during the winter months, most of them are solitary birds. Pairs form during the breeding season, and there is usually little bonding between different pairs. Occasionally, unstable colonies consisting of several pairs are formed. Colonies are more likely to form if there is a shortage of suitable nesting habitats or if primary nesting habitats are clustered.
Breeding pairs defend nesting sites. The size of the territory itself varies greatly among pairs and populations. Males and females in a pair both protect their relatives, nest and chicks. During the breeding season, frequent encounters were observed at one of the breeding grounds. Territory defense ends after breeding is complete.
Fun fact: Grebes eat their feathers. They ingest them more often when the diet is low in digestible substances, and it is believed that this is a way to create pellets that can be thrown away to reduce the appearance of parasites in the gastric system.
Grebes are primarily diving birds and prefer to dive and swim rather than fly. They are diurnal birds and look for food only during daylight hours. However, during courtship, their voices can also be heard at night. Birds rest and sleep on the water. It is only during the breeding season that they sometimes use temporary nesting platforms or nests left behind after the young have hatched. They rise out of the water after a short run. The flight is swift with fast wing beats. When flying, they stretch their legs back and their neck forward.
Social Structure and Reproduction
Grebes do not reach their sexual maturity until the end of their first year of life, but usually do not breed successfully in their second year. They lead a monogamous marriage season. In Europe, they arrive at the breeding site in March/April. Beginning of breeding season — from the end of April to the end of June, weather permitting, but also in March. Grow from one to two broods per year. Pairs may begin to form as early as January. Once in breeding areas, great grebes begin to make breeding efforts only when the appropriate conditions occur.
The most important factor determining the start of breeding is:
- amount of habitat covered available for building sheltered nests;
- favorable weather conditions;
- water levels in reservoirs;
- availability of sufficient food.
If the water level is higher, much of the surrounding vegetation will be flooded. This provides more cover for protected nests. Warmer temperatures and richer food can also lead to earlier breeding. Nests are built from aquatic weeds, reeds, thickets and seaweed leaves. These materials are woven into existing aquatic plants. The nests are suspended in the water, which protects the eggs from land-based predators.
The “real nest” where the eggs are laid rises out of the water and is distinct from the two surrounding platforms, one of which can be used for copulation and the other — for rest during incubation and incubation. Clutch size varies from 1 to 9 eggs, but the average is 3 — 4. Incubation lasts 27 — 29 days. Males and females incubate the same way. According to Russian research, great grebes only leave their nests for 0.5 to 28 minutes.
Interesting fact: Incubation begins after the first egg is laid, which makes embryo development and their output is asynchronous. This causes a sibling hierarchy when the chicks hatch.
The nest is abandoned after the last chick has hatched. Brood size is usually 1 to 4 chicks. This number differs from clutch size due to sibling competition, bad weather, or interruption in incubation. Young chicks fledge at the age of 71 to 79 days.
Natural enemies of the great grebe
The parents cover the eggs with material from the nest before leaving. This behavior effectively protects against the main predators, the coots (Fulica atra), which prey on the eggs. When danger arises, the parent closes the eggs, dives into the water and swims out in a place more distant from the nest. Another anti-predator behavior that helps grebes to hide their eggs is the construction of nests that are completely or partially suspended in the water. This protects the eggs from any terrestrial predators.
Interesting fact: To avoid predation, adults carry chicks on their backs until 3 weeks after hatching.
Carrion crows and magpies attack small grebes when their parents leave them. Changing water levels is another reason for the loss of offspring. According to various studies in the UK, continental Europe and Russia, there are 2.1 to 2.6 young per clutch. Some of the chicks die of hunger because they lose contact with the parent bird. Adverse weather conditions also have a negative impact on the number of surviving chicks.
Interesting fact: Protecting the great grebe in the 19th century became the main goal of the British Association for the Protection of Animals. The dense, silky plumage of the chest and belly was then widely used in the fashion industry. Fashion designers used it to make fur-like pieces of collars, hats and muffs. Thanks to RSPB protection efforts, the species has been saved in the UK.
Since fish is the main source of food for the great grebe, people have always pursued it. The greatest threat comes from anglers, hunters and watersports enthusiasts, who increasingly visit small water bodies and their coastal areas, so the bird, despite the preservation of natural areas, is becoming increasingly rare.
Population and species status
After the number of Great Grebes decreased as a result of hunting interventions and habitat degradation, measures were taken to reduce hunting for them, and since the late 1960s there has been a significant increase in the number of individuals. In addition, the species has significantly expanded its area. The increase in numbers and expansion of territory is due to the eutrophication of waters due to increased nutrient intake and thus a better supply of food, especially white fish. The construction of fish ponds and reservoirs also contributed.
Interesting fact: The number of individuals in Europe is from 300,000 to 450,000 breeding pairs. The largest population exists in European Russia, where 90,000 to 150,000 breeding pairs are found. Countries with over 15,000 breeding pairs are Finland, Lithuania, Poland, Romania, Sweden and Ukraine. Between 63,000 and 90,000 breeding pairs hatch in Central Europe.
grebes have historically been hunted for food in New Zealand and for feathering in Britain. They are no longer threatened by hunting, but may be threatened by human impacts, including lake alteration, urban development, competition, predators, fishing nets, oil spills and bird flu. However, they currently have a Least Concern Conservation Status according to the IUCN.
Great Grebe is one of the species that will be particularly affected by climate change. A research team studying the future distribution of European nesting birds based on climate models estimates that the species’ distribution range will change significantly by the end of the 21st century. According to this forecast, the distribution area will decrease by about a third and will simultaneously move to the northeast. Possible future distribution areas include the Kola Peninsula, the northernmost part of western Russia.