Speaking of pigeons ...

Pigeons feed their offspring a cheese-like secretion known as pigeon

milk. The "milk" is rich in fat and proteins, and it is secreted and vomited from the crop, which is a type of gullet pouch.

Carrier pigeons have been honoured for their

war efforts, including Gustav, who carried the first report to mainland England about the allied powers landing in Normandy.

In the 1800s, there were up to five billion

individuals. But the pigeons consumed crops, and extermination campaigns made them go extinct in 1914.