MARSH HARRIER: CHARACTERISTICS, HABITAT, MIGRATION - HISTORY - 2024

The marsh harrier (Circus aeruginosus) is a bird of prey, belonging to the Accipitridae family. This species is characterized by having a long tail and wide wings, which it holds in a “V” shape, while it performs its classic light flight.

In addition, the species is known for the enormous distances it travels in the migratory process it carries out. This movement is done mostly on water, contrary to the rest of its kind, which does it on land.

Marsh harrier. Source: Paco Gómez from Castellón, Spain

The distribution of the marsh harrier ranges from Europe and Africa, in the northwestern region, to Asia and the northern area of ​​the Middle East. Its habitat is swamps and open plains.

In this species a marked sexual dimorphism is evidenced. The female is a dark rusty brown shade and larger than the male, which is light brown.

Due to the decrease in the populations of this animal, mainly motivated by the destruction of its habitat, it is currently a protected bird in many countries. This has caused the IUCN to include it in its list of protected species.

Behavior

Marsh harriers are not very territorial, although during winter, females tend to displace males from feeding territory. However, outside of the reproductive season, they both rest together on land.

This species flies slowly and at low altitude. They can also glide and glide. Adult males have a faster and more agile flight than juveniles or females.

In addition to flying, the Circus aeruginosus walks and jumps. This way of moving is used while retrieving prey, collecting nesting materials, and looking for chicks that wandered away from the nest.

characteristics

Coloration

The marsh harrier has some characteristics that differentiate it from other species of its genus. In relation to this, while gliding, its wings form a dihedral.

Males

The plumage of the males is generally reddish brown, with pale yellow stripes, which stand out mainly on the chest. The shoulders and head are greyish yellow.

The iris, the limbs and the legs are yellow. They have a thick, black, hooked bill.

As for the wings and the tail, they are pure gray, with black tips. The lower and upper wing regions are apparently similar. However, on the inside the brown has a lighter tone.

While it is flying, whether viewed from below or from the side, the Marsh Harrier shows its three characteristic colors: brown, black and gray.

Female

The female of this species is chocolate brown. In contrast, the throat, the upper area of ​​the head, the extremities and part of the upper dorsal region are yellow. The eye area is dark, which makes the eye stand out.

Young boys

Both males and females, during the juvenile stage, resemble adult females. However, they have a darker brown dorsal side, and are reddish brown or rusty yellow underneath. In relation to the eyes, they are brown.

Size

Circus aeruginosus is sexually dimorphic. The females are approximately 45 to 50 centimeters long, with a wingspan of 111 to 122 centimeters. Its weight could range from 390 to 600 grams.

On the other hand, the male has a maximum length of 45 centimeters and a wingspan between 97 and 109 centimeters. These can weigh between 290 and 390 grams.

Habitat and distribution

The marsh harrier is distributed in Western Europe and north of the African continent. Likewise, it is found from Asia to Japan, in Australia, New Guinea, New Zealand and on some islands in the Indian and Pacific oceans.

Most of the western populations are migratory. Some spend the winter in the more temperate areas of the south and west of the European continent. Others migrate to the Sahel, the Nile, Africa, Arabia or the tropical region of Asia.

These birds live in open regions such as savannas, grasslands, and fields. Also, they could be found in swamps, desert steppes, and in agricultural and riparian areas. In many of these areas, the vegetation is low and dense. It is unlikely to live in mountainous or wooded areas.

Its habitat can vary depending on the geographical location. For example, in eastern North America, the marsh harrier is found primarily in wetlands, preferring regions rich in cane (Phragmites australis). In contrast, those who live to the west live in higher lands, such as desert steppes.

Migration

Circus aeruginosus migrates, during the summer season, to eastern, central and northern Europe. In winter, adult females and juveniles travel to the Mediterranean, while others cross the Sahara to reach Africa.

This trip is usually done by making long and propelled flights over the water, contrary to the rest of the Accipitridae, which migrate by making high flights over the land.

The maximum passage through the Mediterranean, according to what various studies carried out in the area reflect, occurs in the month of September. In this migratory movement, the marsh harrier crosses the sea following the coastline.

This species has long wings and uses powered flight to travel long distances over the sea. In this way they tend to fly in a broad front.

Flight strategies

During migration, it can fly 300 to 550 kilometers nonstop. However, it could use small tracts of land to allow its high flight or as places to rest.

Research on flight strategies shows that the choice of routes, by land or over the water, is little influenced by the deflection of the lateral winds.

In relation to the frequency of the migratory trip, adults make it more frequently than young people. However, among adults, males migrate in greater proportion than females.

Likewise, when Circus aeruginosus is grouped in flocks, it flies at a lower altitude than when it does so alone or in small groups.

Feeding

This bird feeds mainly on frogs, however, it also hunts small mammals, snakes, insects and lizards. In addition, it is a predator of chickens, eggs and birds. When they are sick or injured, the marsh harrier captures them to consume them.

The marsh harrier has a keen sense of sight, although it also uses its ears to locate its prey.

Like the other raptors of its kind, its flight is low and slow. It glides over flat, open terrain, with its wings in a “V” shape and its legs dangling. When it spots a prey, the glide turns into a sudden swoop, to hunt it down.

Occasionally, it may hide behind vegetation, waiting to jump unexpectedly on the animal. Also, they can find their prey on farms or eat dead animals found on the roads.

Carrion feeding is more frequent in youngsters, possibly due to their little experience as hunters.

The diet may depend on the availability of the prey found in the habitat. In areas where small mammals abound, they form almost 95% of the Marsh harrier's diet.

Reproduction

The reproduction stage can begin between the months of March until May. Males and females are monogamous, although some males may be polygynous, being able to mate with up to 5 different females in one season.

Males show particular behaviors during the mating season. This courts the female with a very showy flight. Thus, it ascends rapidly, to plummet, almost touching the ground. In this movement it turns, turns and makes some sounds.

The nest is built on the ground, for which the female and the male work together. This brings the sticks and grass and the female intertwines them, thus creating a space to nest.

Reproductive behaviors

The moment in which the female will lay the eggs is notorious. This one perches near the nest, almost without moving. In addition, it does not take flight, unless it is in the face of a strong threat. During this time, the male feeds her, providing her with prey.

When the young hatch, after 33 to 38 days of incubation of the egg, the female spreads her wings over them, thus protecting them from predators and inclement weather.

The male will be the one who provides food for both the mother and the young. When the female goes to meet the male, she flies after him, until she picks up the food that she left on the ground. Also, the male can release the prey while it is flying, being caught thanks to the ability of the female.

In the nesting season, the Circus aeruginosus becomes territorial. The site where the nest is located is defended by both the male and the female. They can attack any animal, including other hawks, or man, if they approach the area.

Communication

The marsh harrier is especially vocal in the reproductive period, especially when they are around the nest.

During courtship, she makes quick, serial notes. Also, it has a feeding call, which is more frequent during the chick rearing stage. This is characterized by a piercing and repeated sound, made by the female. The male responds with a low-pitched vocalization.

Youngsters vocalize a series of notes, to get the attention of their parents or when they see them flying overhead.

References

1. Wikipedia (2019). Western marsh harrier. Recovered from en.wikipedia.org.
2. BirdLife International (2016). Circus aeruginosus. The IUCN Red List of Threatened Species 2016. Recovered from iucnredlist.org.
3. Global Raptor Information Network (2019). Species account: Western Marsh Harrier Circus aeruginosus. Recovered from globalraptors.org.
4. BirdLife International (2019) Species factsheet: Circus aeruginosus. Recovered from birdlife.org.
5. Fouad Itani (2016). The Western Marsh Harrier (Circus aeruginosus). Brid life Lebanon. Recovered from spnl.org.
6. Nicolantonio Agostini and Michele Panuccio (2010). Western Marsh Harrier (Circus aeruginosus) Migration Through the Mediterranean Sea: A Review. Journal of Raptor Research. Recovered from bioone.org.
7. Nicolantonio Agostini, Michele Panuccio, Alberto Pastorino, Nir Sapir, Giacomo Dell'Omo (2017). Migration of the Western Marsh Harrier to the African wintering quarters along the Central Mediterranean flyway: a 5-year study. Avian Research. Recovered from avianres.biomedcentral.com.
8. Limas, B. (2001). Circus cyaneus. Animal Diversity Web. Recovered from animaldiversity.org.
9. Dijkstra, Cor, M, Zijlstra. (1997). Reproduction of the Marsh Harrier Circus Aeruginosus in recent land claims in the Netherlands. Research gate. Recovered from researchgate.net.