Avian pox ?

No Phil, it looks like a blood filled tick to me & with any luck should fall off soon ...hopefully is under the eye & will leave the bird with a wound but this should heal over ok!  I believe it can be quite energy sapping especially if there's more than one!  Other more experienced people will know more than I do about this!

Phil, go to www.lakelandbirdkeepers.co.uk/minor_ailments where there is good info about ticks albeit about Parrots!

Google images is great when you know what your looking for..thanks

Hi Phil,  I agree with Wendy that the Great Tit in your photo has a tick which hopefully will drop off once it has gorged itself of the birds blood;  I understand that in some severe cases ticks can cause anaemia but is often not life threatening to the bird unless it has several ticks at the same time where it can weaken a birds immunity; 

so you can compare your photo to a case of Avian Pox I have added a photo of a Great Tit which has the dreaded pox lesions;   

Morning
I have observed a lethargic blue tit on my bird feeder thus morning it dew my attention because it appeared to be feeding very slowly ... upon viewing in the spotting scope it has a huge growth above one eye. Could this be avian pox and if so should I discontinue feeding...we have daily visits from various finches and the occasional woodpecker. Any advice would be welcome.

Thank you

Can you get a pic of your BT Freebird for a definite ID! As previously stated a tic can cause lethargy whilst drawing blood from the bird!