The adult male Zebra Finch above left has an orange beak rather than the usual bright red (above right).
This adult male has beige plumage rather than grey-brown including brown throat-barring and a brown and white striped tail.
These beige females also have a brown and white striped tail.
The Zebra Finch above left has moulted or lost its zebra-striped tail. The ones above centre and right have anomalous tail feathers.