A bit of ornithology in Clairmarais
The Romelaere National Reserve (in Clairmarais) is teeming with various bird species. It must be said that our ponds and their banks are a dream biotope for hundreds of migratory species! Here is a small list of the species that we meet the most in the marsh: water hens, various ducks, coots, grebes, herons, swans, egrets, bittern, little bittern, kingfishers... A real paradise for lovers of ornithological walks!
mallard
The mallard is the best known of all ducks. We see it everywhere, domesticated and wild. the audomarois marshes does not escape its colonization.
The male mallard is recognizable by its shiny green head during the breeding season and its yellow beak. After the nuptial period, around June, it moults and takes on its eclipse plumage (beige) and loses its remiges. At the end of the summer, his "green collar" returns. The female, on the other hand, has a brown beak and beige and brown plumage.
The mallard is a not very shy duck and acclimatizes more and more to the presence of man. The latter barely deviate when approaching the bacôve, like the Eurasian coot in the Clairmarais marsh!
The mallard lives in groups (gregarious species) and reproduces frequently with other duck species. It lives on average a few years but could approach thirty years of life expectancy in an unpolluted environment, devoid of hunting activity.
The mallard is a dabbling duck. It thus feeds mainly on the surface, in particular on plants. The duck remains an omnivorous species. It also feeds on seeds, worms, batrachians, insects, small fish... In this regard, it is common to meet ducks in the marsh fed by humans with pieces of bread, this which is not good for them or for the environment! Find out in this article why it is dangerous to feed ducks bread.
The reproduction of the duck is particular. It is customary for the males, in flocks, to pursue the females for an almost forced mating, often without a courtship display. On the other hand (a positive point!), the mallard is monogamous and never changes female during a breeding period.
This starts in March-April. In the spring, the brooding period obliges an incubation of the eggs (about ten per brood) for 28 days.
Outside of these breeding periods, females are loyal to a territory.
The teal
The green-winged teal is the smallest species of surface duck. Its weight varies from 250 to 500 grams.
We recognize the winter teal by its black wings on the outer side, with a green mirror on its inner side. The teal has a white belly, a blunt-tipped beak, and gray webbed feet.
In the breeding season, the plumage of the male is then distinguished by an almost reddish colored head, barred with a green stripe itself bearing a creamy white border on its sides. It also presents during this period a horizontal white bar on the edge of the wing. Its beak is gray-black. The rest of the year, the male wears an eclipse plumage (beige-brown), just like the female.
To feed, the teal dips its head under water to taste small insects, fish and molluscs but also and above all plants and seeds. To help it in its task, its beak fitted with slats filters the water to retain small organisms. It requires only 25 grams of food per day. The teal feeds mainly at night or at dusk, especially in winter, and can sometimes travel thirty kilometers to find this food.
If it is uncomfortable on land, the teal flies magnificently well and knows how to take off very quickly. The green-winged teal lives in small groups and flies in flocks of over 1000 ducks during migration.
summer teal
The garganey is a teal-sized duck and could be mistaken for the latter, if we disregarded the gray color (including light bands) and not green of its wings.
Garganey has a long, gray beak. In mating season, the male wears a colorful nuptial livery and has a reddish-brown head marked by a wide downward-curving white eye stripe.
The breeding season takes place in May. The incubation of the ten eggs per season lasts between 21 and 23 days.
At the end of August September, the teal migrates to winter, heading for southern Europe and Africa. It returns to our regions in April-May for reproduction.
Shoveler duck
The tiger nut is a species of dabbling and filter-feeding surface ducks, like the teal.
This duck has red legs, a large, elongated, spatula-shaped beak. From October to June, the male puts on his nuptial finery.
The water hen
The water hen, more commonly and simply called "water hen", is common in the Audomarois marshes. It flourishes on our rivers but also in the banks with dense vegetation.
This pigeon-sized animal is easily recognized by its yellow-tipped red beak, black body, black plumage and white spots on the rump. Its yellowish legs are not webbed.
An omnivorous bird, the water hen feeds mainly on the edges or on the surface.
Quite fearful, she often takes refuge in the banks. However, she does not hesitate to fiercely defend the nest during the brooding period (up to 4 broods per year from May to September). Very faithful, the male and the female water hen do not leave each other until death once in a couple. They form a united family with shared tasks. It is not uncommon for moorhens to adopt chicks from other pairs, to educate them. Lost chicks are thus often collected. Some are even stolen by some females in front of their natural mother's eyes!
Eurasian coot
The coot is often confused with the moorhen. However, everything distinguishes them: it is larger, has a completely black body, a beak that is not yellow but white, surmounted by a frontal plate. This one is a few millimeters wider in the males, which makes it possible to distinguish it (difficult!) from the female. The coot has short legs extended by long webbed and greenish toes (bluish).
The coot lives in groups, nests in banks or reedbeds and feeds by diving. Its diet is omnivorous. In the marsh of Saint-Omer, he loves duckweed, various aquatic plants, small fish and freshwater mussels (anodontes).
It is a partial migrant in certain regions, but the Audomarois marshes have a high population of coots throughout the year.
Not lacking in cleverness, the coot builds its nest visibly on the water, thanks to branches and plants placed along the edge. He is constantly consolidating it and designing it so that this habitat is not impacted by variations in the water level.
In terms of brooding, the female lays 5 to 9 eggs in April and the incubation lasts just over 21 days. Other broods may follow until the end of July. Both parents then take care of raising the young together, dividing the litter into two groups. For this purpose, the male builds a second nest-platform. It takes about eight weeks for the young to be able to feed themselves and fly. They are recognized by their beak and their little red head.
Great crested grebe
The great crested grebe, the largest of all grebes, is perhaps the most majestic aquatic bird of the Audomarois marshes!
There is no difference between the male and the female (no sexual dimorphism). It wears a black cap in all seasons, short in winter, a dark back and red reflections on the sides, a white belly, just like its chest and its long neck. During the spring nesting season, both sexes have a red-orange tuft on the cheeks (erectile area during displays) and a black double crest on the head, replacing the short crown. Juveniles do not have a crest and have a greyish body, and white and black bands on the head, beak and neck.
While the grebe is not comfortable on land or in flight, it thrives on water and is good at diving for food. It can indeed stay 3 minutes under water to catch fish using its slender beak in the shape of a dagger. On large lakes, it is able to go down to 20m deep! It feeds on everything (it is an opportunist), but loves batrachians and small fish, especially cyprinids (roach, gudgeon, bleak, etc.). Sometimes it attacks young perch. He needs almost 200 grams of food every day!
The nesting of the great crested grebe generally takes place between March and July.
Before the nesting period, couples form in winter and offer nature observers an incredible spectacle: superbly elaborate courtship displays.
They are partial migrants. Depending on the climate of their main place of life, they can migrate in winter to the south of France.
Little Grebe
If the Audomarois marsh welcomes the largest of the grebes with the crested grebe, we also have among its occupants the smallest: the little grebe. It takes its name from the color of the chestnut. It has indeed in summer a dark plumage with chestnut spots on the throat, the cheeks and the sides of the neck (nuptial plumage). In winter, its breeding plumage is duller, gray-white with a chestnut neck. With its habit of ruffling its rump feathers, this large pigeon-sized grebe looks like a floating ball of down.
Like the great crested grebe, it is much less skilled in the air or on land than in the water. However, it demonstrates certain abilities to fly during its migrations. On the other hand, in normal times, as it needs about twenty meters of running before taking off, we still don't see it in the water.
Unlike the Great Crested Grebe, the Little Grebe prefers insects and small larvae to fish. It captures them by diving for 10 to 30 seconds maximum. The great crested grebe can last three minutes underwater.
marsh harrier
The marsh harrier is a diurnal raptor found in the Saint-Omer marsh.
As its name suggests, it lives mainly in reed beds. He hunts there for small mammals, small birds, fish, amphibians, insects or eggs.
The harrier is about fifty centimeters high and has a wingspan of more than one meter in full flight.
The female has a dark brown plumage on the crown, the throat and a spot on the front of each creamy white wing. The male has a tricolor plumage, tending towards dark brown with silvery gray wings with black tips.
The gray heron
The gray heron is one of the greatest hunter-fishermen of the Audomarois marshes. With its greyish color, its long neck, its long legs and its slender beak, it is recognizable among a thousand. With a height of a little less than one meter for two kg, the gray heron has a wingspan of more than 180 cm, wings spread.
The gray heron most often feeds on fish, but can also eat reptiles, crayfish, batrachians, amphibians, insects, small rodents, birds, etc.
He fishes on the lookout, on the edge of the river, remaining motionless for a long time. He is helped in particular by his extremely powerful eyesight. He indeed sees perfectly what is happening under water, but also around him thanks to a particularly developed peripheral vision.
When it eats mammals, it spits out hairs that it cannot digest, like the owl.
The heron has been protected since 1974. It has no predators. Thus, it can sometimes live up to 25 years.
Gray herons breed from February to July. They generally nest in heronries (colonies of herons) on the banks of rivers or in trees.
Its presence indicates the presence of fish and amphibians. It is thus a bio-indicator tool.
The Kingfisher
The kingfisher is present in certain sectors of the Audomarois marshes. This bluish bird feeds on small fish and small aquatic animals. It often stays in the same territory where it knows all the nooks and perches that can be used for its hunting techniques. When it detects its prey, it dives with force and swallows the small fish in one go, in the direction of the scales. It then spits out the bones and the pieces that it cannot digest in a ball. When the fish does not present itself in this direction, he turns it over by throwing it in the air and swallowing it in flight.
When it has to feed its young, the kingfisher has to catch nearly 75 fish a day!
Blue on the top and white and red on the underside of the body, the kingfisher measures about fifteen cm and weighs about forty grams.
This bird is a good natural indicator of the quality of an aquatic environment.
The mute swan
The mute swan takes its name from its tubercle, the bump on its beak.
The swan is one of the heaviest flying birds. Its weight on average greatly exceeds 10kg. It also has a wingspan of more than 2 meters.
In the Audomarois marsh, we see them most of the time as a couple or as a family. You should know that the swan is monogamous. Its breeding and nesting period, like many birds, is in the spring. Warning ! During this period, the mute swan can become aggressive. It spits, performs false warning attacks while swimming, or even flying low towards walkers and fishermen. It can easily take off from the ground but also from a body of water.
When the swan “really” flies, it can reach 80km/h. He makes long journeys in large groups by adopting the “V” formation.
Mainly herbivorous, the swan sometimes eats small molluscs and amphibians. On the ground, the swan can eat insects, but also all types of plants and grasses, including market garden vegetables. Many protect themselves against swan damage by setting up low wire barriers on the banks. On average, a swan requires 3,5 kg of food/day.
Little egret and great egret
The little egret is a species close to the heron (Ardeidae) that is found (more rarely) in the Audomarois marshes. About sixty centimeters tall with a wingspan close to one meter, the egret has an entirely white body and a long bluish-black beak.
In the nuptial period, she wears two long fine feathers on her neck, which are also called aigrettes.
The egret feeds on just about anything, but especially small fish.
The Little Egret nests in groups and pairs in reedbeds, banks, even trees. Its reproduction takes place in spring and brooding at the end of April – beginning of May.
In the Audomarois marshes and especially in the Romelaere, we also noticed the presence of the great egret, a wading bird a little larger than a gray heron. It has black legs, a white body, a yellow beak outside the nesting period (the beak darkens a little at the end). During the breeding season, the beak of the great egret becomes orange or even blackish.
The bittern
The Eurasian Bittern is an ardeid wading bird from the same family as herons and egrets. This bird, present in the Audomarois marsh, is one of the endangered species.
The bittern resembles a massive heron with a thick neck, rather short legs and brown plumage. Its head has a dark cap and a dagger-like beak. It measures on average 75 cm for 1 kg and 120 cm wingspan.
The bittern is a mimetic bird, that is to say, pro camouflage! Difficult to distinguish it in its habitat (reedbeds). Like the heron, it fishes, eats amphibians, batrachians, small birds and mammals. He stalks mainly at dawn and dusk.
Bittern is often solitary. As a couple, it nests in the reeds in April-May on a floating nest.
The bittern is finally characterized by its powerful cry similar to a fog horn, heard for miles.
Least bittern
Another ardeid, rather rare and star of the Audomarois marshes: the Little Bittern also called Bittern Bittern. It is one of the smallest types of herons with a height of less than 40 cm for 150 g and a wingspan of about sixty centimeters.
The male has a black crown on his head, just like his back, beige-orange wings, belly and chest, bluish cheeks and a yellow beak with a black tip. The female resembles male but her colors are duller.
The Least Bittern is monogamous. It hunts at dusk on the lookout and feeds on insects and small fish. Its call resembles a kind of bark, a sound similar to a hoarse “rou”.
In winter, the bittern stays in Africa and returns late in May to our marsh for nesting. He leaves at the end of August at the beginning of September.
The national reserve of the Romelaëre ponds in the Clairmarais marshes is home to 4 to 10% of the national population of Least Bittern.
the great cormorant
About twenty years ago, the great cormorant made its appearance in the Audomarois marshes. Our natural environment now has an average of 200 pairs. It is also found on almost all continents of the globe.
The cormorant measures on average 90 cm long for 150 cm wingspan. Its average weight is 3 kg. The male is a little more corpulent than the female. This is the only difference between the two sexes, which both have black plumage, a creamy-white beak, a yellow spot at the corner of the beak and black webbed feet. Juvenile cormorants have paler plumage, with brown backs and white bellies and breasts.
The cormorant feeds mainly on fish under 20 cm, but can attack fish weighing 1,5 kg. He swallows more than 500 grams of fish a day! To fish, it dives violently and can hold a dive for a minute. However, he cannot stay in the water any longer. Not having an uropygial gland to waterproof its plumage like most aquatic birds, it can go deeper but must quickly rise, its body being much more weighted. Once its dive is over, it digests by drying its plumage for hours, taking up a “standard” position. It stands facing the wind, tail and wings outstretched.
Generally solitary, the cormorant becomes gregarious and gathers in colonies during nesting from April to June.
