Autumn - the forgotten season?

Spring, summer, autumn, winter - we all have our favourite. From a young age we learn to identify the distinctive seasons in the UK and how nature reveals when we’re moving from one to the next.

But climate change is threatening the seasons as we know them, and this can impact our wildlife. With records dating back to 1736, Nature’s Calendar is best placed to track, analyse and understand these changes. Yet we know far more about spring phenology than we do autumn.

Spring records outstrip autumn

Thanks to eager eyed citizen scientists across the UK, we have evidence that spring is advancing. Thousands of people have made a ritual of adding records to Nature’s Calendar each spring. From the first bluebell flowering or blue tit nesting, these records give us an insight into the impacts of weather and climate on key biological systems like food chains and bird breeding.  

Delving into the near 3 million phenology records in the Nature’s Calendar database reveals a penchant for documenting spring events. Perhaps it is the fact that the sight of the first snowdrop, fresh green leaf or butterfly a flutter lifts our spirits after a long winter? We're unsure exactly why recording spring events is more popular, but the difference is clear.

We need your help to increase our records for autumn, so that we can better understand phenology throughout the year. 

Tracking autumn events

While spring brings the promise of new life, autumn reaps the rewards of growth and plants and animals prepare for the winter months. The first plump ripe blackberry or shiny conker, the colour changing spectacle of leaves tinting followed by the first, then final leaf dropping from a tree. All these tell-tale signs of autumn can be recorded on Nature’s Calendar. 

Your autumn records help us to answer important questions. What happens, for example, when autumn arrives early and plants like bramble and hazel fruit before the dormice are ready to hibernate? 

The plight of the hazel dormouse

Nature’s Calendar data is being used to investigate how the timings of hazel dormouse hibernation match up with their food availability. As hazel nuts swell and blackberries ripen, hazel dormice (Muscardinus avellanarius) are looking to get enough food to ensure their survival through the winter. Like hedgehogs and bats, these secretive rodents hibernate when food is scarce.

Hazel dormice have an added problem; they don’t eat grass and leaves because they can’t digest the cellulose in them. Instead they need a sequence of flowers, insects, fruit and nuts to almost double their body weight before cosying down for the winter months. Understanding the timings of natural events can inform the management of hazel dormouse habitat in a changing climate.

What were the earliest fruits to ripen last year?

Blackberries, the fruits of the bramble plant, were once again the earliest fruit to ripe (6 August) followed closely by rowan (7 Aug). Holly berries were the last fruit to ripen (28 Sept). While bramble first ripe fruit was two days later than our benchmark year, the average hazel first ripe fruit was four days earlier, on 31 August.

The first time brambles have ripe fruit is by far our most popular autumn event to record, with nearly 400 records. Bramble is an important food source for many animals, giving a long crop through the autumn months. Hazel dormice eat the blackberries as well as the bramble flowers. So having plenty of bramble plants in hedgerows and woodlands is really important for this little rodent.

Hazel is less well recorded, with just under 150 records of first ripe fruit in 2019. The more records we have with a better spread across the UK, the more reliable the data. Location is an important factor in phenology, so we really want to know what’s happening in every corner of the UK. 

What can I record next?

Although the average date for first ripe blackberry in 2019 was 6 August, but keep your eyes on the hedgerows from now onwards. The first has already been spotted this year; an eager eyed recorder found it near Southampton on 24 June. Record blackberries as first ripe when they are soft to touch.

While spring records outstrip autumn ones, a look at our phenology calendar reveals there’s plenty to record later in the year, especially if you track the autumnal changes in local trees and shrubs.

Why not follow a tree through autumn and record all its events, from first ripe fruit or sign of autumn tinting right through to when the last leaf has dropped and the tree is bare. We suggest you find a tree that is local to you, so you can watch it closely for the first sign of each event. There's plenty of trees and shrubs to choose from: oak, horse chestnut, silver birch, elder, beech, rowan and sycamore, to name just a few!