Can you identify these 2 birds?

Bí Glic means be clever and there is a reason why the Oyster Catcher sings these 2 words. Can you think why?

The oyster catcher lend his swimming suit to the gull years and years ago but the gull never gave it back. The oyster catcher now goes around singing ‘Bí Glic’ warning others not to lend anything to the gull.

As the oyster catcher has no swimsuit, they live and feed close to the shore while the gull goes out to sea for food.