We’ve had young of both great spotted and green woodpecker in our garden recently. They are both easily distinguished from their parents. A young great spotted woodpecker has an all red crown. The adult male only has a small area of red on the back of its head and the adult female has no red at all on its head. A young green woodpecker is spotty over most of its plumage, particularly noticeable on front and head. These spots are not present on adult birds.
The damaged house martins nest under our eaves has now been repaired (by the birds!) and nesting has recommenced.