Cercedilla Field Notes: Butterflies

This morning we went for a walk in the European Redwood forest of Cercedilla, and I was captivated by 4 or so white butterflies dancing among themselves and immediately wanted to get a picture of one of them to ID it, but they were too involved in their mesmerizing dance to settle on a flower for a picture so we continued our walk. A bit down the trail my wife said “There is one!” and so I caught it (virtually) and uploaded it to iNaturalist and will use this post as a place to document and reference the different buttefies I discover in Cercedilla!

  • Melanargia lachesis

    • English: Iberian marbled white
    • Spanish: Medioluto ibérica
    • iNaturalist Obervation ID: 297553457
    • Notes:
      • Picture from 13/07/2025.
      • The butterflies fly in one generation from June to August.

  • Nymphalis polychloros

    • English: Large tortoiseshell
    • Spanish: La olmera
    • iNaturalist Obervation ID: 297559959
    • Notes:
      • Picture from 17/02/2025.
      • Near as I can figure this must have been one that hibernated over winter and had just woken up (was probably born in summer 2024 (I think we have the making of a new Bryan Adams song[1])).

  • Callophrys rubi

    • English: Green hairstreak
    • Spanish: Cejialba
    • iNaturalist Obervation ID: 350855112
    • Notes:
      • Picture from 18/04/2026.
      • A single-brooded species, flying from March to June depending on altitude.
      • The undersides of the wings (what we see in the picture) are a brilliant iridescent green — actually produced not by pigment but by microscopic structures in the wing scales that refract light. The uppersides, rarely seen since the butterfly almost always rests with wings closed, are plain dull brown. You can just make out the characteristic tiny white “hairstreak” streak on the hindwing, and the fine antennae with white-ringed tips.

  • Vanessa cardui

    • English: Painted Lady
    • Spanish: vanesa de los cardos
    • iNaturalist Obervation ID: 354310988
    • Notes:
      • Picture from 26/04/2026.
      • The most widespread of all butterfly species.
      • It migrates from North Africa and the Mediterranean to Britain and Europe in May and June occasionally reaching Iceland

  • Pieris napi

    • English: green-veined white
    • Spanish: blanca verdinervada
    • iNaturalist Obervation ID: 354312694
    • Notes:
      • Picture from 26/04/2026.
      • In southern Europe there are three or more partially overlapping generations from March to October.

  • Zerynthia rumina

    • English: Spanish festoon
    • Spanish: la arlequín
    • iNaturalist Obervation ID: 354313672
    • Notes:
      • Picture from 26/04/2026.
      • Endemic to the Iberian Peninsula and southern France.
      • The flight period is generally in April and May with the possibility of a very small second brood in September.

[1]
ChatGPT generated song about the Large tortoiseshell:
🎸 Summer of ‘24 (Tortoiseshell Wings)
(to the tune and spirit of Bryan Adams’ “Summer of ‘69”)

[Verse 1]
I hatched out in late July
Up on a cherry tree so high
The sun was burnin’, sky was blue
Just broke free from my cocoon

I learned to fly that afternoon
My jagged wings in orange hue
Danced through the woods, wild and free
No one could catch the wind like me

[Pre-Chorus]
Oh and I felt so alive
Nectar buzzin’ through my veins
Didn’t know it at the time
But I’d be gone before the spring

[Chorus]
Those were the best days of my life
The summer of ‘24
(Yeahhh)
I was a tortoiseshell in flight
Didn’t care what came before
I was born to roam
And find my home
Behind that old oak door
In the summer of ‘24

[Verse 2]
Me and my kind, we ruled the skies
Drank from thistles, played in pines
Watched the swallows swoop below
Hung with beetles, dodged the crows

But the winds began to shift
The flowers closed, the light grew dim
The songbirds flew, the forest sighed
It was time to say goodbye

[Pre-Chorus]
Found a hollow deep in bark
Tucked my wings and shut my eyes
I held on through cold and dark
Waitin’ for that spring sunrise

[Chorus]
Oh, those were the best days of my life
The summer of ‘24
(Yeahhh)
Frozen still, but still alive
Dreamin’ of those woods once more
I’ll rise again
When warmth begins
And take to skies I soared
Since the summer of ‘24

[Bridge]
And now the snow has gone
The light is climbin’ high
I feel it in my wings again
It’s time to kiss the sky

[Final Chorus]
Yeah, those were the best days of my life
(Summer of ‘24)
I was just a spark in the sun
Now I’m back to fly once more
And though I’ll fade
I’ll never trade
That season I adored
The summer of ‘24
Yeah, the summer of ‘24

Thanks for reading and feel free to give feedback or comments via email (andrew@jupiterstation.net).