Alexander and Vitaly Drozdov were walking along the Mazā Jugla River (map) outside Riga, Latvia, one spring day when they heard some weird splashes coming from a distant inlet.

"We decided to come closer to see what is happening," Alexander says by email.

The brothers, both photographers, discovered two mute swans struggling in the water, their necks desperately entangled.

Surprisingly, the birds paddled over and allowed Alexander to gingerly separate their entwined necks and wings. Meanwhile, Vitaly filmed the rescue, which took place in 2009 but has only recently gone viral on Facebook and on YouTube.

"Honestly, I was really surprised when [the] swan [swam] to my feet, like he heard and [understood] what I was saying," Alexander says.