Year of temperature extremes results in peaks and troughs for wildlife

Press release
A male brambling in the snow
Published : 13 Dec 2018

Fluctuating extreme temperatures ranging from an arctic -14 degrees centigrade[1], to a sizzling +35[2] have resulted in a roller-coaster year for wildlife, says the National Trust.

The prolonged, harsh end to the winter in February and March with the ‘Beast from the East’, mild May and sunny, hot weather in June and July resulted in wildlife reacting in an extraordinary way with some having record years and others struggling.

As one of the largest landowners in the UK, the conservation charity is responsible for a huge amount of habitats and wildlife. 

Keeping a close eye on the weather and its resulting impact on nature gives the Trust some idea of the challenges and opportunities it’ll need to respond to in the future.

Good year

This was a record year for the rare large blue butterfly with numbers reaching a peak, not just in the south west, but globally[3], a good year for bats, including the rare horseshoe bats[4] and there has been an abundance of fruit and fungi.   

There was also unexpected movement by certain species either with numbers increasing dramatically - such as the migrant silver y moth seen in its highest ever numbers at Mount Stewart in Northern Ireland[5] -  or species arriving in new places, such as the dark green fritillary, also recorded at Mount Stewart.

The hawfinch success story continued with numbers of this rare and elusive finch reaching their peak with 400 birds spotted in Sussex and 600 in Surrey during March.

Bad year

At the other end of the scale, the sudden cold snap at the end of February resulted in a massive kill of invertebrates on the east coast with thousands of shellfish (including lobsters) starfish and fish washed up with many birds also suffering badly including guillemots, shags, fulmar and kittiwakes. 

Nettle feeding butterflies such as the small tortoiseshell, red admiral and comma also suffered despite the good weather, which could be because they were targeted by parasites and pesticides, or affected by climate change. 

Dr David Bullock, head of species and habitat conservation at the National Trust said: “This year’s unusual weather does give us some indication of how climate change could look and feel, irrespective of whether this year’s was linked to climate change.
 
“It’s becoming less predictable every year to gauge what sort of weather we are likely to experience, and what this means for our wildlife.

“We need to ensure that we continue to look after the land in our care and work with others to create joined up areas of the countryside, in effect nature corridors, to enable wildlife to move around easily if needed, to survive any type of weather. 

“This is something that we are aiming to do more of with our ambition to create 25,000 hectares of new, high-quality habitat by re-purposing 10 per cent of our land by 2025.”

Background information – the year in further detail

In only the fourth time since the early 1960s[6], the whole of the UK experienced a more ‘traditional’ winter with snow falling across many of the areas of the country in January, February and March.  Storm Eleanor hit our shores early in January, swiftly followed by warmer than average temperatures before winter set back in.

The most severe of the cold weather was heralded by the ‘Beast from the East’ which brought minus double digit temperatures, severe wind chill[7] and snow to many parts of the country and affected much of continental Europe at the end of February.  This was closely followed by storm Emma and the ‘Mini beast from the East’ which saw another swathe of snow cover some parts of the country. 

Many rare birds arrived from the continent in February and March due to the cold weather which was also being experienced throughout Europe.  Birds pushed westwards included the fieldfare, redwing, golden plover, lapwing, snipe, jack snipe and woodcock. 

A scattering of Arctic redpolls were also seen in the east of England, and there were higher than normal numbers of ducks such as goosander, red-breasted merganser and scaup in the north-west.

Snowy owls – predominantly an Arctic species, and a rare visitor to the UK - were also seen at Scolt Head Island in Norfolk in February and St David’s in Wales in late March. 

The bulk of migrants arrived late, particularly swallows and swifts which were still heading north in June.

There were big hopes of a record breaking invasion of rose coloured starlings but after 40 were seen at places including Lundy and Trevose Head in Cornwall in the first week of June things rather fizzled out.
 
Seal pups at both Blakeney and the Farnes have had record years, thought largely thanks to a lack of disturbance and mild weather. 

On the north-west coast at Sandscale Haws, one of the National Nature Reserves that the Trust cares for in Cumbria, the rare natterjack toad population struggled as the heat dried out the pools essential for their survival; some for the first time in 10 years[8].  However, this could result in positive news for the toad next year as the predators of its eggs and tadpoles, such as dragonfly larvae, will have also perished.

The biggest impact was probably on the dune grasslands – which responded positively to the warm weather in that it helped stem grass growth, making the dunes less stable and able to react, as they should, to weather conditions.  This combined with conservation grazing helped to destabilise some areas to create pockets of bare sand which are used by nesting bees and can be colonised by pioneer plants.  

The warm weather also resulted in the rare sight of northern blue fin tuna off of Lizard Point in Cornwall, and record numbers of Mediterranean gulls.  Conversely kittiwake numbers in the south west are on the decline most likely due to a drop in numbers of the small fish that they feed upon.

Other species attracted to this most south-westerly point of the country and now colonising and breeding included various dragonflies such as the small red-eyed damsel, southern migrant hawker, red-veined darter and vagrant emperor.

Some of our rarer butterflies such as the large blue and silver studded blue have had bumper years, largely due to warm, dry weather from May onwards, with some species such as chalkhill blue having second or third broods in late summer and into the early autumn. 

Wasps also made a strong come-back in the north-west and north Wales after a poor 2017.

There was a mixed picture for trees.  Many feared the cold would have damaged early buds, but once temperatures climbed and spring arrived – albeit later and shorter than in previous years - trees quickly sprang into life.  With it came moist air which meant that fruit trees had enough moisture in them to survive the heat that then followed.  This resulted in a bumper year for fruit including apples, brambles, damson, pears, figs and sloes. 

On the flip side however, the dry summer encouraged the spread of pests with the box moth and oak processionary moth spreading north and west from London and the south-east.
 
Many Trust places saw more evidence of ash die back this year than previously with signs of the disease in both young and old trees.

Once the hot weather arrived the majority of the country experienced dry and sweltering conditions with temperatures soaring above 30 degrees for several days, culminating in a two month period of hot weather that even surpassed the summer of 1976.  Fields and meadows looked parched across the country and farmers struggled with having enough lush grass for their animals forcing them to feed animals with hay and silage from earlier harvests[9].

Parch marks were another summer phenomenon; revealing parts of our history never seen before particularly the layout of the former mansion at Clumber Park in Nottinghamshire and the layout of the 19th Century garden at Hardwick Hall in Derbyshire[10].

The wild fires in the uplands which burned for three weeks through June and July on Saddleworth Moor in Greater Manchester and Winter Hill in Lancashire ripped through over seven square miles of moorland and bracken, destroying precious habitat for ground nesting birds and reptiles in particular.  The peat that burned will take thousands of years to recover and it will take up to 40 years for heather to become mature and diversify.

Much of the country experienced a ‘second spring’ in the Autumn with strong grass growth, with some parts of the country recording a second showing of spring flowers such as violets and primrose.

Animal ecologist, Peter Brash said: “This year’s weather has been the most remarkable of my lifetime, with a bitter March leading into a pleasant spring and a heatwave summer which actually exceeded the famous ‘long hot summer’ of 1976, and an exceptionally mild autumn. 

“The impact on wildlife has been massive, with many species reacting in an unprecedented manner such as large blue butterflies which had a record breaking year and migrant moths such as the hummingbird hawkmoth were also widespread this year.

“The good year for adult butterflies might not be good news for caterpillars however as numbers crashed after the 1976 drought due to larvae not having adequate food as a consequence of plants withering in the heat.  Next year will therefore be one to watch.”

Further month by month highlights

January

  • Warmer than average temperatures across Britain (except for Scotland and the far north of England) resulted in some bats coming out of hibernation to feed at dusk

February

  • Started mild but quickly became much colder with below average temperatures
  • Lots of movement of wading birds down into the south-west along coasts and rivers looking for unfrozen ground to include woodcock, snipe and common sandpiper and also rarer birds such as the green sandpiper

March

  • Another cold and snowy month, lapwing and golden plover, redwings and fieldfare all moving to south and west coasts.
  • The Lizard – at the tip of Cornwall experienced third bout of snow which is virtually unheard of in any one winter

April

  • Extreme flooding at Charlecote Park in Warwickshire at Easter with 60 per cent of the parkland completely under water.
  • Marsh harriers breeding and hares boxing at Orford Ness in Suffolk.

May

  • Large movement of swallows mid-month (almost a month late), swift movements late than usual with birds still travelling north in June.
  • Avocet and lapwing breeding on the grazing marsh at Orford Ness

June

  • Storm Hector hit north Wales and northern England with high winds and heavy rain resulting in fallen trees and a storm surge that wiped out colonies of beach nesting little terns.

July

  • The rarely seen purple emperor butterfly was spotted at Sheringham Park for a third year running, suggesting Norfolk now has its first breeding colony[11]
  • The dark green fritillary butterfly was spotted at Mount Stewart in Northern Ireland for the first time.  This is thought to be thanks to restoration of the parkland. 
  • Large numbers of the rare silver studded blue butterfly up at Bolt Head in Salcombe, Devon.
  • Migratory locust was spotted on the Lizard, and co-incided with a small number of other records along the south coast.

August

  • Warm weather meant that blackberry picking came early with foragers finding enough to make pies at the end of July. The bumper harvest continued throughout August.

September

  • Wicken Fen struggled with the drying out of its fenland habitat which has resulted in wading birds and wildfowl going elsewhere to find food.
  • Storm Ali hit Northern Ireland uprooting several trees with recorded winds of up to 91mph and some National Trust properties were forced to close.
  • A grey phalarope was spotted at Charlecote Park in Warwickshire.  It is incredibly rare to see one so far in-land.  This little bird breeds in the Arctic and will winter in the Atlantic off west Africa or possibly the Caribbean.

October

  • Fungi out in abundance after the rain that followed the long dry summer.
  • Some very late, third broods of adonis and chalkhill blue butterflies spotted in the south-west and clouded yellow butterflies, speckled wood and small tortoiseshell and red admiral all spotted in Dorset on 25 October.
  • Bats still on the wing at the end of October.
  • Big influx of bramblings with an exceptional flock of around 500 birds at Croft Castle in Herefordshire where they have been feeding on beech mast and in stubble fields.
  • Solitary bees spotted across the south east (they usually fly in the spring)

November

  • Goat and sheep count in Cheddar Gorge found that sheep numbers were steady with around 100 accounted for; but goat numbers were down because so few kids survived the ‘Beast from the East’ as they were born between January and March.
  • Deer will be going into the winter in good shape because of the strong growth of grass and other vegetation.  Whether this leads to higher deer numbers in 2019 depends on the severity of this winter.
  • An influx of rough-legged buzzards, with twice the average number seen.  But they seem to have flown onwards as numbers of over-wintering birds seem now to be same numbers as usual.

December

  • Mild weather at the beginning of the month with wasps, honey bees, hoverflies etc still on the wing.

Ends-

Editor’s notes
[1] Recorded in the Cairngorms in Scotland on 1 March.  With the wind, this actually felt like -30 degrees centigrade.  https://www.metoffice.gov.uk/climate/uk/interesting/february2018-snow

Faversham in Kent recorded temperatures of -14.2 degrees on 28 February.

[2] Temperatures of +35.3 degrees centigrade were recorded in Faversham in Kent on 26 July.  https://www.bbc.co.uk/news/uk-45399134

[3] Despite this summer’s record numbers, numbers next year will most certainly drop due to the drought which will have damaged the ant nests which the caterpillar is reliant on for feeding before it pupates.

[4] Bats did well mainly because they got some good feeding in due to the drier weather before going into hibernation.

[5] 355 recorded on 1 September.  Northern Ireland is the upper limit of their range.  The Silver Y Moth was just one moth to have done particularly well this year.  Other uncommon moths seen at Mount Stewart include the black rustic, dark pine knot-horn, lunar yellow underwing and round-winged muslin.

[6] The country experienced bad winters in 1981/82, 1985 and 2010.

[7] The daily maximum temperature on 1st March 2018 at the National Trust’s Tredegar (Blaenau Gwent) was only -4.7 °C; the lowest March daily maximum temperature on record for the UK, and the ‘feels like’ temperature was widely around -10 °C.

[8] In a wet winter there can be more than 40 seasonally flooded pools, whereas in a dry summer, like this year, less than five pools retained any water at all. 

[9] Rob Macklin, head of farming for the National Trust says: “Farmers have had a mixed year with the prolonged winter resulting in many farmers being forced to pay a high price for winter feed in March when they would usually expect to start turning their animals out into the fields for grazing.  The late spring and dry summer meant that silage yields were lower for some than usual, although silage and hay harvests were generally good although earlier than normal.  With the hot weather some farmers had to tap into these resources early due to lack of grass during the prolonged dry spell. 

“Thankfully though, once it rained and after a second flush of growth thanks to the mild and dry autumn, animals have been able to stay out in the fields for longer – in some instances by two-three weeks which has helped re-balance food stocks for this year.”

[10] For more see: https://www.nationaltrust.org.uk/features/parch-marks-revealing-hidden-history

[11] The purple emperor is Britain’s second-largest butterfly. Despite its size, it’s one of our most elusive insects. It is rarely seen because it typically spends most of its time flying high in the tree canopy. 

B-roll footage is available to download via Dropbox at: https://www.dropbox.com/sh/of1aq12hluv5ii0/AACgWH9hXn0-lHmep8IclvQpa?dl=0