The National Bird of Denmark is the Mute Swan. It Scientific Name is Cygnus olor. It was Officially Adopted in 1984, replacing the Skylark Alauda arvensis.
So far as I can determine the swan was not officially granted status as the National Bird of Denmark by law but by a popular vote held by either Danish Television or Denmark Radio.
The male Mute Swan (known as the cob) is generally larger than the female Mute Swan (known
as a pen) and is also distinguished by a larger knob on its beak.