Like our visitors I think it’s safe to say many of our birds have been hunkered down out of the wet weather.
The most notable sightings this week have been a marsh warbler which has been showing well since last Sunday out on our Wilderness trail and a common tern which has been regularly seen from Paddy’s.
You may be wondering why a common tern is a notable sighting? After all we have hundreds of breeding terns here at Saltholme every year, in fact we proudly tell our visitors how we are one of the largest inland breeding colonies of common terns in the UK.
Well this common tern is slightly younger than the rest and looks somewhat different, which for a while led to a bit of confusion amongst many of our visitors.
The bird in question is a Portlandica common tern.
As far as my understanding goes (which on occasion is limited), the name refers to the stage of the terns plumage – the “portlandica phase”. This is a phase that all common terns go through in their 1st year. Usually whilst in their "portlandica" plumage the bird remains in Africa, they’re not yet mature enough to breed; so why waste their time on an exhausting journey North, that would by all accounts be a complete waste of time.
Occasionally though there’ll be an overly keen youngster; just like with our own teenagers, that just can’t wait and decides to try their luck anyway. So they set off with the more mature birds for the summer breeding grounds.
So that explains what a Portlandic common tern is:- but what is the difference.
-Well, they’re more or less the same size as an adult bird, but with a few significant differences.
The bill? Instead of being bright orange with a black tip, the bill is very dark with only a hint of orange at the base by the birds head.
The legs? Again not the usual bright orange you’d expect from a common tern, they’re much darker almost black.
The above features are somewhat similar to a roseate tern which we do get from time to time here at Saltholme, but the Portlandica tern is lacking the long tail of a roseate, and is much more ‘common’ like.