Approx 4cm long.
No interactions present.
It might be more likely to be Map-winged Swift owing to its being extrememly common in our neck of the woods, Common Swift appears to have only 2 reliable records in N.I. since 1980.
Your larva above is a very good likeness for the Map-winged Swift in ukleps. I've never actually seen the larva but have seen the adult many times- its very prolific on moorland.
... the distribution of Common Swift! I was searching online and saw images of Common Swift larvae and thought, thats it!
I'd be happy if you want to add the Map-winged swift ID.
It certainly does look like the Map-winged Swift larva but Im not sure Im confident enough to add the ID based on the potential for there to be other candidates. Maybe just let the hare sit for others opinions ot be offered, or if you think its it then go ahead?
Had another look in ukleps Philip, the details are exact. Little paired spots on top of the segments and a double wrinkle between each segment. I think its it and would happily agree the ID.
Also had a look at Ghost Moth, similar but not as similar as Map-winged. Do you have any other images of your caterpillar, eg a side view?
I took one other picture which was from the same angle and even more blurred. (I was with someone who, understandably, gets a bit annoyed when I constantly stop to take pictures of bugs, plants, birds and lizards!)
Great website! Just had a look and the length of the larva alone (I thought approx 4cm but 35mm is close enough) suggests Map-winged Swift. It certainly was not as small as '20-25mm'.
Yeah if it was over that then its unlikey to be the Common Swift.
Lat/Lng: 54.5656, -5.9324
OS grid ref: NW458260