Finally, as adults they are bright white with neatly contrasting black primary feathers.
They are an eye catching sight well worth looking out for as they glide above the sea!

In their fourth year, the majority of the black feathers have been replaced with white ones. The few remaining black feathers give away their age!

In their third year, their head colouration becomes that of an adult! Still much black remains across the wings, back, and tail...

This individual is at the end of its second or start of its third year, it is noticeably whiter than the juvenile!

Juveniles are even trickier, sharing features such as their brown toned plumage and white chin patch.
Still, with a bit of practice, they can be distinguished!

So, there you have it!
From fluffy down, to a mixture of browns, whites, and greys, through to the smart white and grey of an adult, Herring Gulls are an excellent species to get stuck into for learning about moult and ageing!

Now, the plumage is that of a winter adult! No brown is mixed in with the grey of the back and wings, and the face and neck is heavily streaked.

The bill is yet to fully yellow, still being pale pink at the base suggesting this is a sub-adult, though soft parts do develop at varying rates!

Suddenly, the wings are largely grey and the primaries have distinct 'mirrors'. The iris is also turning pale and much of the black on the bill is gone. The red gonys spot is developing!

Still, features like the brown in the wing and tail feathers show that they're still a way from being an adult!

The characteristic grey feathers start coming through in the mantle and scapulars in their second year.

The all-black juvenile bill also begins to change colour, taking on a pale pink tinge. One day it'll be the characteristic yellow and red!

Once their down is replaced, they are a mix of white, grey, and brown. Key features to look out for are the 'piano-key' appearance of the greater coverts, and the white notches in the tertials!

This individual has replaced some mantle and scapula feathers. New ones have a distinct anchor pattern!