Little Glass Ostrich Ink Bottle with Bakelite Lid and Box

Anyone know what ostriches have to do with ink ?The ink has long dried up, apart from some which has occasionally transferred itself to the label on the bottle or the box.
The bottles are 5cm tall, have  helpful(for gripping) rings moulded around the lower half and a satisfying bakelite lid. They come in their original boxes.
Made in China.