Stunning summer plumage Spotted Redshanks and Ruffs at Slimbridge and the cunning breeding strategy of the male feader Ruff

  

Ruff

 

I spent Friday at  Slimbridge with two particular target birds in mind, namely the Spotted Redshank and Ruff ,both of which go through a truly metamorphic moult into summer breeding plumage.

The Spotted Redshank transforms from a rather plain, mainly pale, plumage into being almost completely black with the white spots which give it its name. It breeds across northern Scandinavia and the northern Palearctic and migrates  south to the Mediterranean, southern Britain, France, tropical Africa, and tropical Asia for the winter. As soon as it leaves its artic breeding grounds it starts to mount into its pale winter plumage and by the time late summer migrants reach our shores they have either fully or partially moulted. It is hence somewhat usual to see these birds in the UK in their black dinner suits.  Failed breeders , however, leave their artic breeding grounds earlier and indeed two recently arrived at Slimbridge in full summer plumage, thus generating an irresistible urge for me to visit, watch and photograph these avian gems. In only a week or two they will be in full moult, hence the urgency to visit.

 

The two birds have been mainly on the south lake which faces into the sun for most of the long summer days. Friday was forecast to be light cloud providing, hopefully, ideal viewing conditions.

 

So on arrival it was straight to the south lake and there were the Spotted Redshanks dozing on one leg as is their wont in the middle of the lake. Through the scope they were really stunning but a little patience was required to wait for them to wake up and feed, hopefully moving a little closer. After an hour or so they started to feed and wandered close enough for some half decent photography. The numerous Black-headed gulls on site were, for reasons unknown, occasionally very intolerant of then, bombing them and causing them to move on.

  

Spotted Redshank

The other bird that I particularly wanted to see, a black morph Ruff in full breeding plumage, was also on the south lake. It spent most of its time on the distant far shore but did obligingly spend 5 minutes feeding and washing on one of the nearer islands before it too was flushed by a gull. Ruff breed in northern Europe and the Russian Artic but reasonable numbers spend the winter on English wetlands.

 

The summer plumage and breeding strategy of the Ruff is complex and rather fascinating. There are three male morphs which adopt completely different breeding strategies. 85% of the males in summer plumage have strongly coloured black or chestnut ruffs and stake out and occupy small mating territories in a personal lek, perhaps just 1m square, usually with bare soil in the centre. Here they actively court females and display a high degree of aggression towards other resident males. About 14% of the males are so called satellite males which have white or mottled ruffs and do not occupy territories; they enter other males leks and attempt to mate with the females visiting the territories occupied by the resident black males. Resident males seem to tolerate the satellite birds because, although they are competitors for mating with the females, the presence of both types of male on a territory attracts additional females. Very recently another male morph has been discovered which accounts for just 1% of the male population. This has been named the male faeder and it is a female mimic. These are intermediate in size between males and females. The cunning feader male gets full access to the male leks together with the females and can hence steal matings when the females crouch to solicit copulation! One disadvantage of this strategy is that the faeder males are often mistaken for females by the regular males! Another bizarre recently discovered fact is that these female mimics have much larger testes than the ruffed males!! I guess someone has done their Ph.D. on the size of Ruff testes!

 

Two breeding plumage males were on the south lake representing the more numerous black and satellite morphs. The black morph was particularly striking and posed with its Elizabethan ruff fully displayed for just long enough to get a photo. The two males were obviously still high on testosterone such that when they bumped into each other they would start displaying and even fighting.

   

Although I spent most of the day in the south lake discovery hide, I did spend some time in the recently reopened Hogarth hide where three Green Sandpipers and a pair of Cranes with two chicks had been reported. The Green Sandpipers did put in a somewhat brief and distant appearance. A Slimbridge volunteer told me June 10^th is known locally as Green Sandpiper day as this is the day breeding males, which play no part whatsoever in incubating eggs or raising young, start to appear back from their artic breeding grounds.

 

The Cranes keep to cover to protect the chicks when they are first hatched but the chicks at the Hogarth hide were quite well developed and the parents obliged by bring them out into the open to feed. I had assumed that chicks of this size had passed the maximum danger of predation but the volunteer told me that this is, in fact, when they are in most danger as they start to wander from their protective parents – fingers crossed little ones. 

 

 Footnote – my blogs are posted with sometimes rather imaginative spelling and grammar due to my extreme dyslexia!