yes, it is.
If someone is in a good mood and walking along there is no reason they can't whistle or hum. If you are in an office then constantly whistling to amuse oneself is irritating to those around you. If the woman is whistling at one of the opposite sex it's just as rude as a male whistling at a woman.
The present participle for "whistle" is "whistling."
You can politely ask your coworker to stop whistling by approaching them in a friendly manner and expressing how the noise is distracting you. It's important to be respectful and understanding of their habits while also communicating your needs. This can help prevent any tension in the office.
What is it when you hear whistling and no one is there?
There It Go (The Whistling Song) by Julez Santana
Not 100% sure on this but "The whistling wind"?
Whistling Warbler was created in 1878.
Whistling in Dixie was created in 1942.
Whistling in Brooklyn was created in 1943.
Whistling Smith was created in 1975.
Whistling Heron was created in 1824.
Not so much bad luck but in Slavic countries it is said to bring poverty. And in other countries pest animals like mice or snakes. Whistling on-stage is considered very bad luck indeed.