The apparent meaning of the ahadith narrated from Sayyiduna Zayd bin Khalid al-Juhani and Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) from the Prophet (peace and blessings be upon him) indicates that, in the matter of announcing it, there is no difference between a small and a large amount of lost property (luqatah) (both are equal).
It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) passed by a date.
He (peace and blessings be upon him) said: "Were it not that it might be from the charity, I would have eaten it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12096