Q: What is the status of lost items that make their way into my yard?

A: A person’s yard (chatzer) or property can acquire for him even without his knowledge, provided that the property is secure (or that the owner’s home is adjacent) and that the item is likely to be found by the person. Thus, if the lost item is one that the finder can keep, e.g. it has no siman or is in a place where mostly gentiles live, the owner of the chatzer acquires the item (C.M. 268:3).

Conversely, if the lost item needs to be publicized and returned, you are required to do so.

If there was no siman, but the item fell into your property before the owner was aware of the loss, according to some authorities it is considered yei’ush shelo midaas and you cannot acquire the item even after its owner became aware of the loss and abandoned hope.

However, you can declare ahead of time that you do not want your chatzer to acquire such lost items until after the owner abandons hope, and then you can take the aveidah after sufficient time passes (Shach 268:2; Nesivos 262:1; Hashavas Aveidah K’halachah 5:8).