DALS WILDLIFE SITE { WILDLIFE OF NORTHERN ENGLAND}

WILDLIFE OF NORTHERN ENGLAND

Wading birds-2 Oyster catcher Haematopus astralegus

This species of wading bird is very common and is instantly recognisable, being a large , sturdy pied wader. The plumage is black above, except for the white rump, base of tail and wing bar. They are white below, except for the black breast { the throat is also blackish in summer}.

The bill is an orangey red colour, the legs are reddish as are the feet. this accounts for the birds genus name of haematopus which derives from the Greek haima, meaning blood + pous meaning foot. The eyes are also red. 

Oyster catcher-in an upland meadow in northern England.

Photo by Dal.

In relation to its body size the wings are medium length, the tail medium short, neck medium short, the bill medium long and the legs medium length. The body length is 42cm, the wingspan 83cm and both male and female weigh 540g. They are impossible for the layman to sex in the field.

The flight is direct at moderate speed; walks or runs on the ground; wades in water;occasionally swims. The voice is a shrill and penetrating "Kleeep", a shorter "pic pic" and a series of loud piping notes, especially during the breeding displays. it is a noisy excitable bird. 

Lifestyle and Feeding habits of the Oyster catcher.

The oyster catcher breeds in Iceland,the Faroe islands { Here it is the national bird where it is referred to as tjaldur } and northern Europe; along the coast of France; the north western Mediterranean; north east Adriatic; Greece and the Aegean coast of Turkey.

They also breed in northern Britain mainly around the Irish sea coasts of Britain and Ireland. During the winter they may be encountered in large numbers at estuaries in the south west of England.The birds are highly gregarious outside the breeding season.

They feed by touch and sight, however, the method of feeding depends greatly on habitat and individual birds.  They feed on a variety of prey including bivalve mollusc, particularly cockles, mussels and when in land earth worms. Cockles are located by touch as the bird probes in the mud.

They employ one of two methods for gaining access to the flesh inside the shells. The method is either-a, by "hammering", where one part of the shell is continually subject to short, sharp blows, and b, by " stabbing", where the bill is inserted in the gap of the shell until it is open enough to shake out the flesh from its container.

Individual birds use one or the other techniques which some ancestral instinct inspires. Studies have revealed that individual birds may have one of two types of bill {beak}, a pointed one which is ideal for the stabbing technique or a broad tipped bill utilised for prising open or hammering , again this is genetic. Small prey such as lugworm may well be eaten whole. The food is often washed before it is consumed. They may also take, small crabs, periwinkles, dog whelks and their ilk, to rocks which they use as an anvil in the manner of a song thrush. 

Breeding and young

Many pairs arrive at their breeding ground as early as March. At this period of time many territorial disputes often occur, until, the rightful tenants take up occupancy. The chief mating display is one of much "piping"calls, which is rendered with the bill pointing downwards, these displays deter would be interlopers and strengthen the bond of the pair. they are monogamous and long term togetherness is common place.

They nest on the shore, on shingle beds, among rocks, in sand dunes,among grassy banks, or crops , and on the banks of rocky streams. The nest is but a shallow scrape {typical of most waders} which may be lined with small stones or pebbles, shells or even rabbit droppings all of which act as camouflage.

The eggs which number 2-3 measure about 57 x 44 mm. the colouring is a buffish yellow or stone, marked with brown spots. They may be , on occasion, olive or light brown, boldly blotched or streaked with black or even grey markings. These birds are volatile when disturbed at the nest, drawing attention away from it, flying around uttering their familiar shrill shriek.

The incubation period is between 24-27 days and is carried out by both parents, however, the greater majority seems to be undertaken by the female. Incubation commences when the last egg has been laid. The chicks are precorial { hatch with down having open eyes and capable of leaving the nest within a few days of hatching.}. They fledge at around 34-37 days. The chicks are cared for by both parents, they are brooded when small. Independence varies from soon after fledging up to as long as 26 weeks or so. the birds raise just one brood per year. birds that survive predation and disease may live for 12 years. 

Oyster catcher with chick

Photograph courtesy of John Haslam

CONSERVATION STATUS AND PROTECTION

In the UK, the oyster catcher is on the Amber list of conservation concern primarily because of European breeding numbers that occur here and localised populations.

Breeding numbers seem stable in England, but less so in Scotland. this is thought to be due to an increase in the choice of less favourable nesting habitat chosen by some birds, which result in predation and trampling.

The birds status in the UK  = Migrant/ resident breeder

                                          Passage/ Winter visitor.

In the UK there are three conservation ratings. Green, Amber and Red. All species that occur in the UK are on one or the other lists.  These lists are formulated under the UK Biodiversity Action Plans. {BAPs}.

Those that are on the Green list of conservation concern have no immediate conservation concerns.

Those that appear on the Amber list have suffered declines in population/distribution of between 25-50% over the last 40 years or so.

Those that appear on the Red list are classed  as Priority species because they have suffered declines of over 50% in population/distribution over the last 40 years or so. Species unfortunate enough to be included on the Red list are subject to a Species Action Plan, {SAP} .

Most SAPs are now being implemented across the country under Local SAPs in an attempt to halt the declines and eventually to reverse them. Many examples of these species are featured on this site.  

For another in depth article with  historical observations and more images visit ---

http://hub.me/ahcOY 

Reuse of images

The images on this page may  be reused. However, the name of the relevant author must be attributed along with any accompanying license.

Rocky upland streams are ideal nesting habitat 

Photo by Dal.

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