Emile de Groot has given a good answer; We do not know yet.
However, in the sea-coots, there is more often a number of dying in bad weather; They are overtaken or the fishes go deeper down on the seabed and the weaker sea-coots cannot find any food anymore.
They live the majority of their lives on the water, and come only to land to breed.They are therefore also severely affected by weather and disasters such as oil stains, because they float on the water. The mortality of the sea-coots is therefore often a first indicator that something goes wrong at sea. 20,000 Dead Sea Coots is more than we have seen in a long time, there were large deaths in the years 80 and 90, but lately no longer actually.
It is now being investigated, but there are some people who think it has something to do with the container ship that lost 291 containers on the night of 2 January at Ameland.Then there was also storm, and from that time we see the birds flush, and possibly the containers and their salvage also disturbed the hunting grounds of the sea-coots. The animals that are found are made out and have intestinal problems such as infections, but the research is still busy. The fact that the containers or their content have something to do with it is speculation at the moment.
But well, we don’t know…
I think the answer from Emile de Groot can be correct.
According to an article by the NRC, it may have to do with the fact that two humpbacks were observed near Texel.A sea-Cooet eats 20 different fish and it is possible that these humpbacks have eaten fish near Texel. [1 as a result, the sea coots that are usually not older than a year seem to be malnutrition.
Thank you for asking me this question C茅line D茅camps (Quora user).
Coincidentally there was something about it on the radio at NPO1.
The critters are still being investigated for diseases and other potential causes.So it was not quite sure what the cause was.
It most likely seems that they have died by malnutrition.
If the bird arrives in an area with little fish and cannot get away because of the bad weather, it can die.This is more often observed by biologists, usually it is a few.
The birds looked very slimming.Had no visible injuries or signs of disease. Most were quite young and so inexperienced. That provisional conclusion sounds very plausible.
Nature is sometimes very harsh.