اعراب جمله أن الطيور تهاجر شتاء

The sentence “أن الطيور تهاجر شتاء” is analyzed as follows: “أن” is a substitutive particle with no grammatical status. “الطيور” is a proper noun in the accusative case with a clear sign of accusative (fatḥah) at the end. “تهاجر” is a present verb in the nominative case with a clear sign of nominative (ḍammah) at the end, and the hidden subject is “هي.” “شتاء” is a time adverb in the accusative case with a clear sign of accusative (fatḥah) at the end. The verbal sentence is composed of the verb and the subject, with the subject in the nominative case serving as the predicate of the substitutive particle “أن.”