"The bird is eating bread."
Translation:Ptak je chleb.
Ptak (there's no any 'ą' here) is simply the noun 'bird'. "Ptasie" is the neuter singular and not masculine-personal plural (any plural that is not denoting a group of people that has at least one man) for "ptasi", which would be the word "bird" treated as an adjective. You can check it here
I believe you most probably encountered this word on a box looking more or less like this? ;)