Clouded Yellow Colias croceus
Habitat
The Clouded Yellow is an unpredictable annual migrant to Britain arriving from southern Europe in spring and dispersing northwards, occasionally occurring in huge numbers - about once every decade. It may be expected in many habitats where there is an abundance of nectar sources.
Identification
It has rich deep-yellow wings with solid black borders, which, on the female, are dotted with yellow spots. There is a pale female form helice. It almost always rests and feeds with its wings closed.
Flight times
The first arrivals are usually seen in May and June, with further immigrations possible between July and September. Numbers are supplemented by locally bred butterflies as it has a very rapid breeding cycle. It may be recorded until October.
Food plants
Food plants are clovers, Lucerne, and Common Bird's-foot-trefoil.
Distribution Maps
2005-2009
2010-14
2015-19
2015
| No of tetrads | 23 |
|---|---|
| First sighting | 05/06/2015 |
| Last sighting | 21/10/2015 |
2016
| No of tetrads | 17 |
|---|---|
| First sighting | 03/06/2016 |
| Last sighting | 14-09/2016 |
2017
| No of tetrads | 14 |
|---|---|
| First sighting | 25/05/2017 |
| Last sighting | 24/08/2017 |
2018
| No of tetrads | 15 |
|---|---|
| First sighting | 18/04/2018 |
| Last sighting | 08/09/2018 |
2019
| No of tetrads | 17 |
|---|---|
| First sighting | 08/07/2019 |
| Last sighting | 19/09/2019 |
2020
| No of tetrads | 20 |
|---|---|
| First sighting | 11/04/2020 |
| Last sighting | 31/08/2020 |
2021
| No of tetrads | 7 |
|---|---|
| First sighting | 30/05/2021 |
| Last sighting | 08/08/2021 |
2022
| No of tetrads | 21 |
|---|---|
| First sighting | 20/03/2022 |
| Last sighting | 09/11/2022 |
2023
| No of tetrads | 7 |
|---|---|
| First sighting | 09/05/2023 |
| Last sighting | 10/09/2023 |
Similar or Easily Confused Species and ID Hints
The rich golden yellow of the Clouded Yellow and bold black margins on the upper sides make it unlike any other British butterfly.
Brimstone Gonepteryx rhamni
The pale "Helice" form of the Clouded Yellow could be confused with a Brimstone. All forms of Clouded Yellow and Brimstone rest with their wings closed, hiding the bold black margins. The key differences being the shape of the rear edge of the wings and the shade of yellow, Brimstone having a slightly greenish tint, particularly the females.
