If you have visited the wetlands or coastlines of Europe, you may have been lucky enough to spot the striking markings of an oystercatcher. They have black heads, backs, wings and tails, with contrasting white feathers running along their undersides and up to their shoulders. In flight they show a white rump and a white stripe running along each wing. Alongside this they also have bright orange bills, red eyes and pink legs. Oystercatchers weigh from 380 to 520 grams and have wingspans of 72 to 83 cm. Outside of the breeding season, most of them have a white chin strap.
The oystercatchers name is a bit misleading as they only very rarely eat oysters. Their main diet includes cockles and mussels such as this one here, which the bird is expertly hamering open, but they can also use their beaks as probes to collect worms from soft soil and mud and invertebrates and crustaceans from on and below the waters surface.
Historically Oystercatchers were almost always seen along coastal estuaries and shorelines, and this is where they are still most common during the winter, but over the past 50 years or so, some of them have been moving noticeably inland for nesting. They are resident in the UK and the western shores of Europe, but there is also a migratory population that breeds in Northern Europe, western Russia and eastern asia, these birds head south in the colder months and spend their winters along southern European, Asian and African coastlines.
Nesting for oystercatchers begins in early march when established pairs return to their breeding territories and single birds that are at least 3 years old, attempt to attract mates using a noisy head down display. After pairing each pair creates a scrape nest that is on the ground and well camouflaged. It usually includes only a small amount of material around its edges and can be on a shingle beach, among farmland, on lake islands and I have even seen them nesting on the gravel covered roofs of some large buildings. Each pair will lay between 1 and 4 mottled eggs that are olive in colour and measure about 5 and a half centimetres long. Both adults incubate the eggs and after 24 to 27 days the chicks hatch out. These are precocial and can see, stand, walk and even run just a few hours after hatching. At first they are covered in a layer or mottled down, they lack the long orange bills and blend in well with their surroundings. Unlike most other wading birds, the chicks do not feed themselves straight away, with both parents providing most of their food for the first few weeks. As the chicks grow, they gradually moult to have similar markings to their parents and at around 30 days old they are able to fly and have the beginnings of the characteristic long bill. Young birds stay with their parents throughout the summer whilst they learn how to find enough food for themselves. In the autumn, the birds move away from their nesting territories often joining large coastal flocks and it is around this time that young birds will finally be independent. They will only raise one clutch of chicks in a year and Oystercatchers are thought to be monogamous if they are succssfull at raising chicks and will return to their chosen nesting area year after year. One pair was recorded returning to the same site for 20 years in a row!
Over the past 25 years, oystercatcher numbers have dipped by 22% in the UK, which has been attributed to several factors, including higher levels of predators, disturbance from people and pets and changes of land uses in wetland areas. Whilst researching for this video, I found that until the 1700s oystercatchers were known as Sea pies and I wanted to include that in this video but didn’t know where, so here you go. They have an average lifespan of around 12 years with the oldest ringed wild bird surviving for 40 years, one month and 2 days. Here is an example of an oystercatchers call.
Some of the footage and images used in this video were obtained using creative commons licences, the originals can be found at:
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#birdwatching #birding #wildlife
18 авг 2023
