The sand martin is a brown bird with white underneath.

崖沙燕是一种腹部为白色的褐色的鸟。

《柯林斯英汉双解大词典》

Emu is a large Australian flightless bird, similar to the ostrich but with three-toed feet and grey or brown plumage.

鸸鹋是一种大型的澳大利亚不会飞的鸟，类似于鸵鸟，但是有三趾的脚和灰色或棕色的羽毛。

youdao

The night that Christ was born a little brown bird shared the stable with the Holy Family.

耶酥诞生的那天晚上，一只棕色的小鸟分享了神圣家庭的稳固。

youdao

The brown mud of its banks was a rich text of bird prints, and my boot marks joined the tracks of heron, cormorant, gull and egret.

BBC: England��s ghostly South Downs Way

Brown rats may be a pest in the UK but in South Georgia they are pushing indigenous bird species to the brink of extinction.

BBC: Rat eradication project on South Georgia set to resume