Most birds will roost together and this means only the outside birds are exposed. They can fluff up and this prevents the mosquitos from biting..... but it does not stop them from annoying your birds. Brids need 12 hours of sleep - if they don't get it - you can expect them to be grumpy and not get along well with anyone - you or the other birds.
If you were a responsible owner, and smart - you would simply put a mosquito net over the cage. Even if they are not biting your birds - this will stop them from doing touch and goes they annoy the birds.
That said - birds do not have allot of blood. It does not take much blood loss at all for them to become anemic. And remember - birds are genetically pre-disposed to not show any outward signs that they are sick - since this is what a predator will focus on. So, your birds could have lost allot of blood and be on deaths door knocking loudly - and you would not notice it all by looking at them.
Get a net.
Of course, all birds can die from west nile virus or any other mosquito passed diseases.
Just like with humans, it can be itchy and annoying as well as transmit diseases. The biggest worry is the wasps and bees, these can be deadly to birds.
Just as humans can get itchy and sick with a mosquito bite, is it the same with indian ringneck parrots, alexandrines and budgies?. I have my birds in the large cage outside in the garden. They must be facing many mosquitoes at night time. But they are healthy. I also wonder that if mosquito bite is dangerous for birds, then what do the wild birds do. They are also being stung by mosquitoes several times at night but yet seem fine.
