There is a similiar scam going on with dogs, where the missionary is just looking for a good home for them.
Find where their ip address is coming from on both e-mails, wouldnt it be something if they werent in Spain lol but some random country in Africa or South America
If you really want to take them for a spin ask them to put your name on a piece of paper and take a picture of it next to the birds, and tell them you will ONLY pay through paypal to avoid scammers, also ask for references and their phone numbers the birds vets, people they know ect, along with talking to them on the phone.
I have a feeling you wont get a reply back.