The bald eagle is now officially the national bird of the US, after President Joe Biden signed a law on Christmas Eve bestowing the honour upon the white-headed and yellow-beaked bird of prey.

The bird has been a national emblem in the US for years, appearing on the Great Seal of the US - used on US documents - since 1782.

But it had not been officially designated to be the national bird until Congress passed the bill last week, sending it to Biden's desk to be signed.

"For nearly 250 years, we called the bald eagle the national bird when it wasn't," said Jack Davis, co-chair of the National Bird Initiative for the National Eagle Center, in a statement. "But now the title is official, and no bird is more deserving."

Not everyone has always agreed about the national status of the bald eagle.

Founding Father Benjamin Franklin objected to the creature being chosen to represent the country, calling it a "bird of bad moral character".

But not all of Congress shared Franklin's sentiments.

Bald eagles, like other eagles worldwide, had been seen by many as symbols of strength, courage, freedom and immortality for generations, according to the US Department of Veteran Affairs. And, unlike other eagles, the bald eagle was indigenous only to North America.

The legislation designating the bald eagle as the national bird was spearheaded by Minnesota lawmakers. The state is home to what Senator Amy Klobuchar described as one of the nation's largest bald eagle populations.

The bald eagle is also protected under the National Emblem Act of 1940, which makes it illegal to sell or hunt the creature.

The birds were once on the brink of extinction, but the population has greatly increased since 2009.

The bald eagle bill was one of 50 pieces of legislation that Biden signed into law on Christmas Eve, including a federal anti-hazing law to tackle violence and deaths on university campuses.