The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Tap Pocket:
Squishy Birds is a virtual farm, where you raise, feed, breed cute little birds. When they are fully grown you can keep them or sell them to buy newer birds.You can play with them by knocking on the glass and can enjoy their funny expression.