Leighton Moss with Goldeneye

Blue skies over Leighton Moss wetland

There's a beautiful blue sky and sunlight  illuminates reed-beds and discovers warm and muted colours in the woods beyond the  fresh-water pools.  All is peaceful and serene.  Signs of new life after a wet and rather dull winter. 
Water-levels are high and mosses are vibrant green where a a moorhen feeds  in the shallows of willow and alder carr.  Scarlet elf cup show on a mossy log.   Catkins show against the blue; hazel, willow,  alder and green birch catkins.  There's a flowering sequence but, like so much in nature,  there is variability, perhaps related to the position and age of a tree.  I look for catkins on the aspen, so glorious in autumn colour last year.   No sign so far. 

A sightings board gives the latest lists of species, There will be resident birds, new arrivals and imminent departures.  Birds are in breeding plumage and in courtship pairs so may be displaying. Some species will  overwinter here and will soon head for their breeding grounds.   These wetlands will be a stop-over for migrating birds where  they refuel and shelter, sometimes awaiting favourable weather. 
A bittern booms somewhere in the reed-beds.  Numbers breeding here have increased in recent years.  They're hard to see but it's evocative to hear their resonating call.
The causeway hide looks out to an islet where mute swan and shag are often seen. But today the light is strong and the shag's breeding crest and green eye show clearly.   A marsh harrier flies over the reed bed.  There's so much to see that visitors may well focus on different species, on different aspect of the scene. 

A lively flock of tufted duck swims to and fro, close to the hide, males showing distinctive breeding crests.  Pairs of gadwall are about and  pintail.  The moment someone calls goldeneye that's my focus, They overwinter here, sometimes in large numbers, and they're stunning ducks.  They're swimming on the furthest reaches of the pool, screened by reeds growing on slivers of marshy ground, with shelduck and coot amongst them.
The adult male goldeneye has a circular white spot below the eye. The large domed head is glossy dark green with a pattern of  black lines on the white flank. One male is sky-pointing in courtship display.  Adult females have a head of chocolate brown and a yellow eye.  Several images shows the orange-pink tip on the black bill which signals the bird is in peak breeding condition.  There's at least one immature goldeneye in the group, showing mottled plumage on the flank and brownish eyes.  
Overwintering goldeneye will include the Scandinavian breeding birds.   Some will breed in the north, in Scotland. They nest in cavities in tree-holes, and in nest boxes.   I reflect on birds whose young many of us never see, either because they migrate  to the fastnesses of remote breeding grounds,  or because they are secretive in protecting nest sites and young.   

Photography- the word means drawn by the light.  Those goldeneye  swam on the furthest reaches of the pool, far out, disappearing behind reeds and a clump of  trees,  following  channels through the reeds.   Strong light falling onto the birds shows them remarkably well, given the distance.   There will be immature birds, first winter birds, in this group.   The eye changes colour as the bird matures- but colour is a gift of the light, not an absolute.  The incidence of sunlight determines whether the glossy dark green is visible on the male's head.   So, back to forensics with photographs.