Rooster Cockerel Chicken Whistle Signed NUMMY (?) on base

I bought this from a flea market.

Still works with a clear and constant note.

Could it be slipware?

Rooster is stamped with NUMMY or WUMMY, something to that effect, on the base.

Measures:

11.5 x 9 x 4.5 cm

Weight:

210 grams

Any suggestions?

Thank you.