These thematic pictures of Птици are analogous to a visual dictionary. The theme "Птици" splits into several parts. For children, especially toddlers from 1 to 5 years old, it is better to divide the sets of cards over several days, or even weeks, so the information is absorbed better. Especially it is true if you are using flashcards to learn the bulgarian language, which is not your native language.
To expand your bulgarian language vocabulary on the "Птици" topic, flashcards games are the best way: