Isidro's Thunderbird

When Isidro's Thunderbird enters the battlefield if you control a 1/2 creature then Isidro's Thunderbird gets +2/+1,
Flying
———{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}
Wow what is this! oh yea a thunderbird! cool
-Isidro