Low butterfly numbers so far in 2024

A greenish yellow butterfly resting on some vegetation
Brimstone. Photo: Warren Port

Butterfly numbers in Dorset reported to this website are down 50% on this time last year.

At the moment (early July) we have 12,815 butterflies recorded, compared to 25,949 at this time last year.

Some species don’t fly in the first six months of the year, but looking at a few which do and comparing to the same months last year (we have left out months where sightings were zero or very few, but all six months are included in the totals):

Brimstone

A greenish yellow butterfly with some brown spots nectaring on a yellow flower

Brimstone. Photo: Donald Simcock

March sightings up: 273 in 2024 compared to 134 in 2023

April sightings well down: 254 to 625

May sightings down: 378 to 707

June sightings down: 45 to 71

Total Jan to June: Down – 984 in 2024 compared to 1,599 in 2023


Orange Tip

A white and orange butterfly with some black markings on a blue flower

Orange Tip and Holly Blue. Photo: Caroline Stringer

April sightings up: 151 to 110

May sightings down: 225 to 362

June sightings: 3 to 15

Total Jan to June: Down – 380 in 2024 compared to 488 in 2023


Holly Blue

A blue butterfly with black and white markings on a green leaf

Holly Blue. Photo: Jill Franks

April sightings up: 59 to 43

May sightings down: 122 to 447

June sightings down: 23 to 69

Total Jan to June: Down – 204 in 2024 compared to 559 in 2023


It is difficult to theorise about the reasons as yet, but total butterfly sightings in 2023 were up 30% on 2022, so we are comparing to a very good year. Short term fluctuations in numbers may be weather-related, so we will be looking to see if our very wet 2023/4 winter may have been implicated; different butterflies overwinter in different stages (see the list on our overwintering page) and some may be more affected by weather than others.

We will watch the rest of the year with interest and hope that numbers overall pick up.

Please send in all the butterfly sightings you can via our Recording Form so we know what butterflies are out there.

5 thoughts on “Low butterfly numbers so far in 2024

  1. Kevin Symes

    I have just returned from a walk through Lodmoor sanctuary, Weymouth, one cabbage white butterfly, a number dragonflies,
    There are a number of Buddleia bushes, however no sign of Peacock,Red Admiral, Tortoiseshell, very surprised at their absence,
    Compared to previous summers .
    Hopefully the situation will improve in the coming weeks.
    Kind regards
    Kevin Symes.

    Reply
  2. Lesley McAuley

    Don’t know much about butterflies but I do know the cat brought in a HUGE moth last night that made my sister scream! Its wings were wider than the glass I caught it in, which has a diameter of just over 3 inches. Released safely

    Reply
    1. Lyn Pullen Post author

      It was probably a Hawk-moth of some sort: they are large! Thank you for seeing it safely released: they do no harm and act as pollinators.

      Reply
  3. Ralph Acampora

    I started my first butterfly garden with many different milkweed & nectar plants. Many of the plants still need to bloom and I have seen only a small white butterfly so far.

    Reply
  4. Gary Holderness

    My own experience so far this year is that butterfly numbers are down.
    I think it’s down the wet winter and colder than usual day time spring/summer temperatures we have in general been experiencing.
    Certainly up to this time (mid July)

    Hopefully August and September will be warmer, less windy and a little dryer.

    Reply

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