Wild birds of declining European species are dying from a thiamine deficiency syndrome
ABSTRACT Wild birds of several species are dying in large numbers from an idiopathic paralytic disease in the Baltic Sea area. Here, we demonstrate strong relationships between this disease, breeding failure, and thiamine (vitamin B(1)) deficiency in eggs, pulli, and full-grown individuals. Thiamine is essential for vertebrates, and its diphosphorylated form functions as a cofactor for several life sustaining enzymes, whereas the triphosphorylated form is necessary for the functioning of neuronal membranes. Paralyzed individuals were remedied by thiamine treatment. Moreover, thiamine deficiency and detrimental effects on thiamine-dependent enzymes were demonstrated in the yolk, liver, and brain. We propose that the mortality and breeding failure are part of a thiamine deficiency syndrome, which may have contributed significantly to declines in many bird populations during the last decades.
Was completely unaware until I heard about it on Swedish public service radio (yesterday I think). Can't find a journalistic article about it in English. Here's one in Swedish from Sweden's only conservative national newspaper (and it's not a tabloid):
Förvirrade fåglar speglar katastrof [Confused birds reflect disaster] | Inrikes [Sweden] | SvD [The Swedish Daily Paper]