Thursday, 5 November 2015

A trip to Portland Bird Observatory Part II - the Invertebrates

For this blog post I will detail a few of the cool invertebrate species that we came across whilst staying in Portland Bird Observatory. Being located at one of the most southerly points in the UK, Portland is ideally placed to receive a whole host of impressive migrant invertebrate species from the continent, in particularly moths. The have recorded well over 1000 lepidoptera species around Portland, and regularly find nationally rare species- indeed, there are several species found almost exclusively on Portland, such as Eudonia mercurella f. portlandica (which is also named after the isle).

A Dark Bush-cricket lurking on the edge of the obs porch wall

It was therefore very exciting to be based at the observatory for a few days, where skinner and robinson traps were placed out in the garden (I use the plural here...nine traps were out most nights!) every night to attract in any interesting moths. Although the time of year wasn't quite ideal for large numbers, we did have a couple of good nights in terms of weather conditions, with perhaps over 200 moths attracted to the traps on the night of the 27th, and then around 100 on the night of the 29th. 

Moth Trapping

28th October
The first morning of my stay saw some good numbers of moths in the traps, with the particular highlights for us coming in the form of Clancy's Rustics, L-album Wainscots, Flame Brocade, Pearly Underwing, Delicate, Grey Shoulder-knots, Feathered Brindle, Vestal, White SpeckPalpita vitrealis and Croicidosema plebejana. This brilliant selection was accompanied with good numbers of commoner species like Feathered Ranunculuses, Beaded Chestnuts and Black Rustics. This was a great start to our stay, with many of the above species being scarce species restricted to the south of the UK.

30th October 
After something of a wash-out moth-wise overnight into the 29th, there was very little to be seen in the traps in the morning. However, conditions improved hugely into the night of the 29th, which made for another great catch. There wasn't quite as much interesting diversity, but just under 100 moths were trapped. This included a lovely micro moth called Spindle Knot-horn, or Nephopterix angustella, along with macro moths such as Shuttle-shaped Dart, more Clancy's Rustics, L-album Wainscots, Chestnut, Diamond-back Moth, Green-brindled Crescent, Scarce Bordered Straw and Silver Y. Another great selection, if a little less diverse than our first trapping experience. 

This is one of my favourite micro moth species, which is commonly found on the continent, but occurs more scarcely as a migrant in the UK. The translucent wings give it the common name of Olive-tree Pearl

Perhaps one of the prettiest wainscots? The L-album Wainscot is again restricted to the southern counties of the UK

Flame Brocade- one of those holy grail moths for an aspiring lepidopterist!! This species used to inhabit Sussex, but has since become extinct and is now thought only to occur as a migrant in the UK. It is resident in the Channel Islands, however

Grey Shoulder-knot

The Delicate (top) and White-speck (lower)- both migrant species to the UK, which are relatively common at Portland

There were commoner UK species like this November/Autumnal Moth, which are just emerging all over the country at the moment (as per the name!). It is virtually impossible to tell November and Autumnal Moths apart aside dissection & genitalia examination

Clancy's Rustic- this species was not recorded in the UK until as recently as 2002, although it has since established itself as a fairly regular moth in the southern parts of the UK

A head shot of the Scarce Bordered Straw (another migrant species)

Nephopterix angustella, or the Spindle Knot-horn

Angle shades

A few of the many different forms of Beaded Chestnut that can be encountered- they can look superficially similar to the Lunar Underwing if you are not careful, but the upper kidney mark is a downward-pointing 'slit' in the Breaded Chesnut, compared to being a rounder oval in the Lunar UW


Aside the moths, there were a few other interesting invertebrate species to look at, including bush-crickets. I was surprised to see four different species of bush-crickets whilst at the observatory, three of which turned up almost exclusively in the obs porch! This selection included the rare Southern Oak Bush-cricket (Meconema meridionale), which is a very recent colonist of the UK, and is only present in the far south of the UK. Dark Bush-crickets (Pholidoptera griseoaptera) and Long-winged Coneheads (Conocephalus discolor) were also cool to see...

Southern Oak Bush-cricket (Meconema meridionale)


  1. Hi Ben, lovely pics. Hate to be picky but Portland Moth was actually named after the Duchess of Portland, not the Isle of Portland. I think there is only one 'modern' record of this species on the island in 1995. Cheers

  2. Thanks for commenting! Cheers for the info on that one- I had no idea that it was named after the Duchess. Nor that the species was super rare there. Thanks for correcting :)