Voor ons in Nederland is het plaatsen van platforms voor broedvogels een nieuw fenomeen, maar in Noorwegen is het al heel lang gebruikelijk. Langs de kust in het noordelijk deel van Noorwegen, in Finnmark, werden in vroeger tijden broedplatforms geplaatst voor de stormmeeuw (zie foto). Deze soort had als grondbroeder veel last van predatoren en door platforms te plaatsen rond boerderijen langs de kust gingen stormmeeuwen daar op broeden. Dat was een win-win situatie, de bewoners gebruikten de eerste eieren als voedsel, daarna werd het nest beschermd zodat de jongen vliegvlug werden en de stormmeeuwen het volgende jaar terug zouden komen. De noodzaak om de eieren als voedsel te gebruiken is er niet meer, maar de platforms zijn er nog steeds en worden nu ook door scholeksters gebruikt.
Hierover schreef Dag Gjerstad van BirdLife Finmark ons het volgende:
The northerners view of the sea magpie
The oystercatcher is an iconic bird in our part of the Arctic, their mid-March arrivals north of the polar circle is a sign of spring and are given significant attention by locals and media. 2-3 months in the shade and a total lack of sun/extremely turbulent weather, including ice & snow, the birds arrival is an omen of better times to come. And messengers are important, my brother living on Baffin Island has a similar situation; snow buntings and snow geese are good news and worthwhile celebrating with solids & liquids. Just like the isolated Norwegian community on Bear Island, the return of the «angels», the snow buntings, is a big day there, very much like the first day of the sun, a few glimpses; a few weeks earlier. You might need to be a northerner to understand this, or a committed ornithologist, however, this is how it works. The oystercatcher is not only a bird, it’s a FRIEND.
Rural people in general are aware & care of the «Tjeld», the Norwegian name of the bird. And are interested in the wellbeing of the thing, just like members of your NGO. And with a special focus on the breeding success. We live next to the sea, many of us live of the sea, literally. And the bird breeds in our gardens, on our doorstep, under the veranda, in the herb beds, next to the chicken stall, on the boatshed/house roofs, but mostly in the tidal zone in and around the property. And often with meagre results since nests are being looted. So what do you do? Shoot the Kelps, ravens, crows and land magpies? As well as trap the foxes, mink, and other mammals? Yes, to some extent, however less and less since new generations have different approaches. And new ideas are being rooted. Like the building of nestboxes, although it’s not a new thing, at all. But spreading, fortunately.
In our area, Toppelbukt, Kvænangen municipality, 100km east of Porsanger, there is significant interest among locals to work with Tjeld, since people are aware of the fact that most of the eggs & young are predated by birds and mammals. Moreover, most of all by sea-fluctation, high tide being The Evil. In Toppelbukt there are not the massive mudflats found in Porsanger, giving opportunities for clusters of common gull/oystercatchers. Our birds are scattered along a gravel tidal zone with 2-500 metres between each breeding pair.
We have also a local situation whereby a frozen ocean causing most semipermanent structures in the tidal zone to collapse as the sea ice brakes them down, moving up/down 4xx a day. Nestboxes for birds are no exceptions. The simple solution to compensate is a metal pipe in the gravel a few metres from max sea lea level, 30-50 cm deep. Blind the pipe in the fall, open the pipe after ice melt in May. And insert the pole with the nestbox, which has be strapped to the nearest birch tree over winter, fast and efficient, no delays. We are expanding every year, next spring will add another 5-10 items as the results are impressing:
- Birds seems to adapt fast, my understanding is that many of them prefer nest boxes to the groundbreeding alternative, especially if they are born in the box?
- No egg losses to mammals and sea fluctuations
- Very few losses caused by larger birds, kelps don’t like the poles, nor do ravens
- Can be further improved if you have problem corvids by strapping a ball of barbed wire with an opening for the oystercatcher. We see that even the most aggressive hoodies thinks twice before entering.
Our oystercatchers feed solely on shellfish as agriculture is non-existent. And almost solely on blue mussels during low tide, to a minor extent on crustaceans. They produce 3 eggs on 25th May as an average, never 4. If eggs are predated, they produce a second clutch of 2 eggs, however very rarely if predation takes place after the 10th of June. By reducing egg predation to almost zero we are halfway through the critical phase of the young bird and mostly left with ground predation hampering positive breeding results, being a different and more complicated matter. We have only the breeding results from the closest nestboxes to our houses, since we have to work for income, besides, but there is no reason to expect the picture to be different; production of 1.3 young per clutch as they depart in the end of August for southern mudflats along the North Sea coastline.
Oystercatchers thrive well in our community, they are increasing annually by numbers, even before the nest box initiative started. The blue mussel, being the main source of food is doing very well and even better with climate change, so lack of food in the breeding season seems to be no bottleneck. Nor breeding locations after more and more nestboxes are popping up, we hope. Non-existent highways with roadkill, few people and stray dogs. Lynxes, volverines and the 3 breeding pairs of white tailed sea eagles prefer cats to oystercatchers, more meat on the bone. They take the canines out during the dusk part of the year. Lastly, the AWD Clubs don’t use the tidal zones, this also helps.
Presentaties Eindsymposium CHIRP
Het gedrag van Scholeksters die in het binnenland broeden
Forteiland IJmuiden blijft superplek voor Scholeksters
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