Sacred And Straw Necked Ibis

Though different in colouring of similar family
Straw necked ibis and sacred ibis in mixed flocks i often see
Sacred mostly white with head and tail of dark brown
Are birds often seen in the parks of the town
Though straw necked mostly dark brown are birds of the countryside
And though often seen in mixed flocks they are not hard to differentiate
Though when it comes to breeding with each other they never mate
With long curved bills for probing for slugs in softer ground
Often in mixed flocks in huge numbers they abound
They both lay white eggs on stick nests over water as birds they are well known
Though similar in some ways they both have ways of their own
Familiar birds in their range many of them can say
Sacred and straw necked ibis i know of but do not see every day.