www.ukbutterflies.co.uk

I have some thoughts but hardly a hypothesis.

First emergences - and I'm not talking about species that hibernate as adults - have become very much earlier in my almost 80 years of butterflying.  For example, Orange Tip is now seen by the end of March.  In my younger days, it was end of April if I was lucky.  Dukes are now mid-April.  When I first met the Duke in about1970, it was a late May species.
 
Climate change is real, but let's not get into the usual discussions as to the reasons.  Milder winters and earlier springs might account for some of today's emergences.  But I offer - for discussion - two other possible factors.

There are more enthusiasts these days who these days track down the early flyers, so maybe greater observer coverage alone might bring forward the 'first sightings'.

But that alone can't explain the early reports in this miserable spring.  Could cleaner air (less coal burning, for example) be a factor?  Some countries still have heavily polluted air.  I wonder what is happening in say China or India?

This all needs research, so let's have the comments.

Jack

It's not just the butterflies, Jack.

For example, when I was a kid it was unusual to see daffodils in bloom prior to the spring equinox. Back then, they were very much an April flower.

Similarly with bluebells, they were generally to be seen through May, along with 'Mayflower', a.k.a., cuckoo flower.

That's long since become a thing of the distant past.

These days, I can expect the following almost EVERY year:

First daffs out in late January

Daffodils in full pomp by mid-March and largely gone over by the end of the first week in April.

First Bluebells out in late March, and virtually gone by May.

Cuckoo flower routinely flowering in late March. It no longer lasts until May (except for some isolated growths that are in shaded areas).

Of course, this is from a British perspective so I cannot vouch for other areas on earth, but I'd be surprised if they weren't experiencing similar phenomena.

Perhaps at altitude it is different as in these places spring is much later, even at lower latitudes.

This year, I saw my first butterfly on 5th January and my first daffodil in flower on 6th January. There isn't much scope for it being any earlier!!

You asked for comments outside of the climate change box Jack.

I agree with a lot of what David wrote too. Undeniably many flowers and insects are appearing earlier year on year.

This year I saw a ridiculously early Cowslip and a few absurdly early Bee Flies. The buddleia and hydrangea in my garden are much more advanced than previous years. The dandelions on my lawn appeared a few weeks early.

I am actually going to agree wholeheartedly with your suggestion that more reported sightings might be a factor. I can say categorically that a lot of my early sightings this year have been because I have spent considerably more time outdoors and travelled about considerably more than in previous years.

I imagine milder weather brings more people outdoors and in turn sightings.

All winters and springs are different, and each species reacts in a different way. This year the orange-tips are out early but the sallow blossom is running late.

This year, here in east Anglia spring has arrived early, but not exceptionally so. Certainly the Snowdrops and Daffodils were early, but things have slowed since then, due to the rain and lack of sunshine. There is some hawthorn on the road verges in flower, but most of it is in bud, as is the horse chestnut, and will flower close to the usual time.

As for the daffodils in flower in January, this may be because of the introduction of new varieties, such as Rijnvelds Early Sensation, which flower much earlier than ordinary ones. However, the April flowering of the Bluebells is real, as they were a May flower in the 80’s and 90’s. Interestingly, they still do flower in May in Cornwall.

A great topic of debate!

essexbuzzard wrote: ↑Sat Apr 20, 2024 9:56 pm However, the April flowering of the Bluebells is real, as they were a May flower in the 80’s and 90’s. Interestingly, they still do flower in May in Cornwall.

I joined the thread to make a comment on Bluebells. Here in South Derbyshire they have been flowering in early to mid May until very, very recently. This year, mid April and some a week prior to that.