Welcome to Zoo Admin.
Whenever a zookeeper makes the motion of feeding, but no food appears, that means the animal is using a food type from an expansion pack that you do not have. If you are referring to the Glossy Ibis made by Pretty Parrot, that uses a food type (Insectivore Chow) from the DD expansion pack. There is no way to add these food types to the original Zoo Tycoon. So, unfortunately, you cannot use the animal in the original Zoo Tycoon since it can never eat. It is possible to change the food type that an animal wants by editing the ".uca" file in the ".ztd" file. A Uca Editing Guide at ZKL describes the line and possible settings. But that can get rather involved, especially since this animal has other inconsistencies in its configuration.
Happy Zoo Tycooning.:original: