KARACHl: The zoo staff had a tough day on Sunday as they were grilled throughout the day by their boss over a`missing ostrich egg` which, according to sources, was eventually recovered when they were threatened to be handed over to police.

The egg was reported missing on Saturday night, they added.

Currently, the zoo has a single ostrich pair and a lone female. The pair had recently laid four eggs.

`I came on Sunday to interrogate the staff over a missing egg which was replaced by an unfertilized egg of the lone female,` he said, adding that a white-coloured fertilized egg could easily be distinguished from the yellowish unfertilized egg.

The `missing` egg, he said, was recovered after one of the keepers admitted that he had taken it away, replaced it with an unfertilized egg and hid the fertilized egg in the bird`s retiring room.

`He also said that he did it on the instructions of the in-charge of birds` cage. I will further investigate the issue and prepare a report tomorrow,` he said.

The ostrich pair, he explained, had not bred for a long time and a lot of care was being taken this time when they laid eggs.