I sell a lot of pigeons and the only way I take payment, when shipping, is a USPS money order from the post office.
In my experience other money orders are often fake.
USPS money oders have a metallic strip and a hologram and are checked against a list of lost and stolen money orders when I use them to ship the birds at the post office.
I suggest sending a USPS money order with delivery confimation, so the reciever has to sign to get it, that way you have a strong case for mail fraud if they don't deliver.
Also do your research on the seller. If they have been selling pigeons for a long time you should be able to find some feedback from other customers.
Keith