Not really. Blue fingernails can be a sign of hypoxia, a lack of oxygen in the blood. This can happen at high altitude such as mountain climbing or flying in a depressurized airplane higher than about 12,000 feet altitude.
blue fingernails
Blue fingernails should look fungi infection
no
shivering
Yes, it can.
Yes. Both shivering and a rapid heart rate are signs of dehydration.
There are many signs of dehydration in blue jays that you can observe. A bird might be weak or have a slow response for example.
dehydration
No, it can be a sign of dehydration/too much iron.
dehydration
If I were you, I would check my drinking water for nitrates. They are responsible for "blue baby syndrome", where skin turns blue, but I don't know about fingernails. nail polish tehe Family Feud answers: nail polish, cold, dead, bruised
Marks on fingernails usually indicate a vitamin deficiency and are not a sign of cancer.