FIELD NOTES
FEBRUARY 2003 continued....
ARTICLES
Sunday 22nd December, 2002
A Window On Global Warming?
The 22nd December was memorable both for its extraordinary mild weather and for the unseasonal observations we made that day.
It started at breakfast when we watched two Jays Garrulus glandarius still collecting and burying acorns in our garden where fresh blossom had appeared on normally summer flowering Hebe. This caused us to reflect on another unusual singular event; the abundant blossom that had appeared on our 40 year old crab tree, Malus 'John Downie', in November.
There was a fine chorus of birds that day which included both Blackbird and Song Thrush in full song. Later that morning we observed a Peacock butterfly Inachis io flying around St. Peter's Churchyard, Tewin. Numbers of this species hibernate annually inside the bells at St. Peter's which are rung at least twice a week. Checks carried out by Peter Walters (Churchwarden) over several years have shown that they remain there, withstanding the noise, vibration and movement of the bells, until emerging in the spring.
The night brought even greater surprises. Returning south along Lilley Bottom Road at 2100 GMT a large mature frog Rana temporaria appeared in our headlights at Stagenhoe Bottom. We stopped briefly to find five more crossing at the same point as well as several crushed corpses in the road. Here were frogs migrating to the adjacent long established breeding pond on December 22nd! Later we learnt that frogs were also seen migrating at about 2230 GMT at Harmer Green, Digswell.
Large numbers of moths were flying that night. In addition to over 100 male Winter Moths Operophtera brumata and two Satellites Eupsilia transversa, our catch included a Pale Brindled Beauty Apocheima pilosaria, a species normally seen here in February and March, which is known to emerge in mid-winter during exceptionally mild weather. Quite exceptional, however, was a live example of the brown lacewing Wesmaelius subnebulosus. This is an early spring species which our records indicate normally flies through the summer into late autumn.
Any members who are interested in the changes that are taking place are encouraged to participate in the phenology study (see below).
Tom and Janet Gladwin
SURVEYS
Have You Seen Your First Bumble Bee, Seven-Spot Ladybird, Or……
Your Observations Could Be Valuable
Through my schooldays in Hertford and the 1950's I approached the end of March with increasing excitement and expectation as I awaited the arrival of the first summer migrants. Would I see my first Sand Martin and first Brimstone butterfly, and hear my first Blackcap and Chiffchaff before the month ended? How great have been the seasonal changes since. Sand Martins may now be seen in the first week of that month, summer migrants such as Blackcaps and Chiffchaffs now over-winter in Hertfordshire, and it is not unusual to see the first Brimstone butterflies in January.
In Digswell, the leaves on our local ash and oak trees regularly open some two to three weeks earlier than when we moved into our home here in 1959. This winter (2002/3) early spring moths such as the Pale Brindled Beauty and March Moth appeared in our traps in December and January respectively.
As I evidenced in the Society's Newsletter (Field Notes. No.1. April 2002) the emergence of the Orange-tip butterfly has advanced by two weeks. These are just some of the responses of our native plants and animals to environmental changes, especially weather and climate. Winters have on average become milder with some birds nesting earlier, and autumns progressively delayed. In addition there have been a series of extreme weather events during the last fifteen years producing exceptionally high temperatures, droughts, floods and storms of unusual force.
Phenology, the study of the timing of recurring natural seasonal events, is essential to our understanding of climatic and weather changes and the response of our wildlife, both now and in the future. Such is the concern about climatic change, and global warming in particular, that the UK Phenology Network (UKPN), jointly run by the Woodland Trust and Centre for Ecology and Hydrology, was established in 1998 to collect and study information on the timing of natural events.
The project, appropriately titled Nature's Calendar, involves interested observers recording and submitting easily identified events. In spring these include the first budburst, leaf and flowers on familiar trees, the first flowers on easily identified plants such as Bluebell and Lesser Celandine, the first sighting or hearing of summer birds such as the Chiffchaff and Cuckoo, and the appearance of the first insects such as Bumble bees, Seven Spot Ladybird, and common butterflies.
Nobody is expected to record every event. At present the study has over 18,000 registered recorders of which just over 2,000 recorded more than 12 events in the spring of 2002. As stated in the Spring 2003 edition of Nature's Calendar News, "even one or two records are valuable".
The historic phenological studies carried out in Hertfordshire, especially from 1876 to 1918, which were the subject of annual reports in the Society's Transactions, are proving of immense value. How interesting and valuable it would be to be able to compare the situation now with that of over 100 years ago.
Like me, are you still excited on hearing the first Cuckoo, seeing the first Swallow, finding the first Bluebell? If so please participate in this important study.
I will be pleased to supply copies of UKPN's attractive booklet Guide to recording spring and autumn events in Nature's Calendar and recording form on request. Please return the recording forms to me and I will forward them to UKPN.
Just as a reminder, here are the first dates that we are looking for:
The first budburst and first leafing of Alder, Ash, Beech, Silver Birch, Horse Chestnut, Elder, Hawthorn, Larch, Pedunculate Oak, Sessile Oak, Rowan and Sycamore.
The first flowers of Wood Anemone, Blackthorn, Bluebell (wild), Lesser Celandine, Horse Chestnut, Coltsfoot, Lady's Smock (Cuckooflower), Elder, Garlic Mustard, Hawthorn, Hazel, Purple Lilac, Oxeye Daisy, Primrose, Dog Rose, and Snowdrop (wild).
The first arrivals of Blackcap, Chiffchaff, Cuckoo, Turtle Dove, Spotted Flycatcher, House Martin, Sand Martin, Swallow, Swift, Willow Warbler, Wheatear and Whitethroat.
The first song and nest building of Blackbird, Rooks, Blue Tit, Great Tit and Song Thrush.
The first Bumble-bee, Queen Wasp, Seven-spot Ladybird, Brimstone, Comma, Green-veined White, Holly Blue, Orange-tip, Peacock, Red Admiral, Small Tortoiseshell, Small White, Speckled Wood, Frogspawn, Tadpoles and Newts.
When did you first cut your lawn.
Please let Tom (contact details below) have your records for this coming Spring and any from last year that you have not yet sent in.
Tom Gladwin
99, Warren Way
Digswell
Welwyn
Herts AL6 0DL.
Tel: 01438 714700.
Email: tomandjanet.gladwin@btinternet.com
Page Six >>
|
