This time we are going to talk about a species of birds named Calidris alba, the order of birds of the Caradriformes group is as diverse as gulls, plovers and shorebirds. The latter forms the family Scolopacidae, which includes the white sandpiper (Calidris alba), also known as the sea brush, like many other shorebirds.
Characteristics
It is a small bird, with a length of 17 to 21 cm, with a general color very white in the distance. The upperparts are ash gray with nice brown stripes. Head gray, except for the forehead and headphones, which are white. The front of the neck and the entire belly white. Black beak, slightly thick black legs. During flight dorsally a white band on the wings, with black tip. Back and dark gray supracaudal.
The Calidris alba, is a bird of 20 to 21 cm long and 40 to 45 cm in length. Its plumage is quite pale in general. The adult has the nuptial plumage with a dark orange hue to the brown plumage of the head, neck and breast, with some fine dark stripes; the upperparts have black feathers with orange grooves and white margins, the tertials with longitudinal orange bands on a black background; the ventral areas are white.
It is known that this particular species is not reproductive as an adult is light gray, with the edge of the springs of the upperparts and white with a dark carpal point which is the young darker, with the flanks of neck feathers yellow and black beaks and notches whitish. Spring costume characteristic of a young Calidris alba more contrasting than adults, with dark pied, creamy sides of the head and checkered back.
Behavior
On short winter days, one often observes, especially along the shores of the Atlantic coast, some very pale-colored wading birds that move quickly and follow rises and falls in the waves. These are snapshots of tridactyl, some travelers are inconvenient to travel thousands of miles from arctic areas where they breed, winter in temperate and tropical areas on land.
The Red Knot as mentioned above, has a good sized and very pale feathered suit, often seen walking along beaches with fast competition as it chases small marsh pulling waves. The adult has a dark orange hue due to the brown color of the head, neck and chest, with nice dark stripes.
With respect to behavior, this depends somewhat on the environment in which it is found. Off the beaches, plains formed by lakes and lakes; when boned, rocky tundra. In most seasons it is found on sandy beaches washed by waves. It is sometimes seen on rocky beaches and is less frequent on salt marshes. It is generally a coastal bird, although some specimens stop at lakes. During the breeding season, it lives outside the Arctic Circle, in fairly dry and rocky tundra, with vegetation of mosses, lichens and low plants, usually near lakes or ponds.
The population can suffer a serious reduction. Some studies show an 80% decline in the Americas since the early 1970s. To migrate, it is highly dependent on some resting areas and is vulnerable to the destruction of these sites.
This small escort goes along the beach as if it were a “mechanical toy” that chased the reviving waves. It is clumsier and more active than most small scolopacids and quite pale for much of the year, which blends well with its dry sand. Sandpipers live in some northern locations, but during migration and winter they can often be seen on coastal beaches around the world.
Food
Their feeding habits differ from species to species in nature and are an aspect that should be observed to distinguish them. The shape of the upper part varies according to feeding needs. Shaggy species bite quickly on soft substrates or to change water.
It chases the waves in search of sand crabs, which are buried in the tidal zone and are easier to spot when the wave falls. calidris alba also scans the sand and mud for other creatures and moves fast while picking up objects from the surface.
Mostly crabs and other invertebrates. It spreads on a variety of small beach animals, including sand crabs, amphibians, isopods, insects, marine worms and small mollusks. You can also consume some carrion. (See Article: Monk Parrot or Gray Parrot)
Birds that overwinter on the south coast may feed on corn chips and other junk food that people leave behind. During the spring it may feed on large numbers of horseshoe crab eggs. In the tundra, it feeds mainly on flies and other insects, as well as some seeds, algae, and leaves.
Members of this species use a very special technique of finding food: they swim in small circles above the water to create an upward vortex that lifts invertebrates to the surface where they can be nibbled. Yellowlegs, like the Yellowlegged Sandpiper Mayor, fish for small fish in shallow water
Breeding
The feathers on the upperparts are black with ocher, orange and white margins and the tertiary shows the longitudinal orange band on a black background.The stomach is white Six non-reproductive, however, are light gray, with white and dark upperparts feathers bordering the carpus, while the juvenile is slightly darker, with yellow neck sides and black upperparts feathers with white elements.
Its breeding area is located around the Arctic, in the northernmost coast of America, Greenland and northern Asia, wintering in the southern part of South America, South Africa and tropical and also in Australia and New Zealand; also wintering in Europe and in the Mediterranean region.
These mating usually occur 4, sometimes 3 to be their breeding processes. In this sense the physical characteristics that can be appreciated are olive green to light brown, with few brown and black spots. Incubation is carried out by both sexes and lasts between 24 and 31 days.
Sometimes, the female lays 2 pairs in separate clutches and she and she broods with each other. Otherwise, the female may have 2 pairs and leave the male specimens responsible for each pair and young when they retire so to speak or when they reach a stage where they cannot reproduce.
The young leave the farm shortly after hatching; one or both parents take care of them. Although at first both parents are present, the female may withdraw after a few days. The young feed themselves. The first flight takes about 17 days of life.
Habitat of the Red Knot
The calidris alba lives in areas of very cold climate in its breeding season, in areas where grasses, mosses and liquids are abundant; outside of this it usually appears in coastal areas, beaches and less frequently in salt pans, ponds and inland waters.
It lives on the coast, occasionally inland. He runs quickly after the waves after the movement of the undertow, without letting the water to touch. Gregarious, flies in compact flocks that move in unison. It can be seen active at night, feeding or flying. It nests in the northern hemisphere towards the arctic regions. Nests on the ground building relatively elaborate nests. Lay 2 to 4 olive eggs.
Their diet is based mainly on small invertebrates; in the breeding season, they capture adults and larvae of flies, beetles, butterflies or spiders; they also feed on crustaceans and in times of little food they may take vegetables. They are also known as summer visitors. Seen in the wetland Rocuant-Andalién in the company C. Bairdii or in small groups, in Concepcipon Bay, Ifarle and channels of El Morro.
It builds its nest in relatively high and open areas, on bare rock, usually in a depression covered with leaves, although they have not been provided by birds. Laying, of 3 or 4 greenish or bluish eggs with brown spots or irregular black streaks, occurs between May and June; they incubate for 24 to 27 days and the hens develop in about 17 days.
The Calidris alba extends in Spain to the sandy coasts of the Atlantic, especially in Galicia, Andalusia and the Canary Islands, being rare in the Mediterranean, appearing here only in some areas, such as the Ebro Delta. It makes large migrations, being a wintering in the peninsula, having few tourists; the stages take place between September and October and between April and May. It is estimated that about 890 – 12,000 specimens are wintering in the peninsula.
Juvenile plumage differs from adults to present more contrast with dark pileus, lateral neck cream and checkered back. During flight there are pale longitudinal bands visible on both wings and pale back, cut vertically by a black band.
