The task is always to spot your next multiple of five of a certain bird in other gardens.
From this thread:
https://www.fairylandgame.com/fbfairy/forums.php?tid=34384 "The birds will not always tell you to spot their own kind, instead they will give you a task to spot any of the 4 birds within it's "group".
Group 1: Wren, Yellow Wagtail, Chaffinch, Singing Bush Lark
Group 2: Nightingale, Bee Eater, Roadrunner, Waxwing
Group 3: Kingfisher, Oriole, Chickadee, Blue Jay
Group 4: Woodpecker, Magpie, Jackdaw, Crane
The Cuckoo is the only bird not included in any of these groups. It is the only bird that will ask you to find other Cuckoos, but it can also ask you to find any of the birds in any of the groups at random."