Nature in Avon Volume 77 Bristol Naturalists’ Society Registered Charity No: 235494 The Bristol Naturalists’ Society aims to stimulate a greater awareness of natural history and geology in the Bristol area. It is a thriving and friendly Society with something of interest for everybody, young or old, professional or amateur. It is actively involved in a long term programme of education, research and conservation. Each year its talks, trips and publications are enjoyed by hundreds of people wanting to find out more about our natural world. For details of membership and activities please see the website at: www.bristolnats.org.uk Nature in Avon ISSN 0068-1040 Receiving Editor: Dee Holladay, [email protected] Editorial Committee: Ray Barnett, Tim Corner, Clive Lovatt, Mark Pajak, Nick Wray. 2 Nature in Avon Volume 77 CONTENTS Editorial . 1 Winter Hoverflies of the Bristol Region Jon Mortin 2 Peregrines Ten Years On Ed Drewitt 8 J W White’s Racy Botanical Articles Graham Avery 13 Lower Writhlington Tip, Radstock Simon Carpenter 20 Chills and Thrills of Plant Sex Alex Morss 29 New Moth Records to the Bristol Region Ray Barnett 35 Land of Limestone and Levels: Lincoln Garland Defining the West of England & MikeWells 42 Phenology Report, 2016 and 2017 Richard Bland 53 The Queen's Hitchhikers Alex Morss 55 A Slime Flux Jean Oliver 59 Slimbridge 72 Years Ago Richard Bland & Martin Davis 61 Seeds of Change Nicholas Wray 66 Geology and Landscape of the Bristol Region Richard Arthur 80 Bristol & District Invertebrate Report, 2017 Ray Barnett 85 Weather Report for 2017 Richard Bland 95 Society Annual Report 2017 103 Treasurer's Report for 2017 113 3 4 Editorial How encouraging to see that natural history recording is alive and well, and that social media is encouraging a new generation to join in! There are Facebook groups and identification websites for almost every group of animals and plants, and Citizen Science is the new buzzword. John Mortin reports that recording of hoverflies has markedly increased as a result of the setting up of Facebook groups, Simon Carpenter describes a family day at Writhlington Batch where hundreds of people searched for fossils, and Alex Morss describes an increasingly popular New Year Plant Hunt organised by the Botanical Society of Britain and Ireland. Some 6,000 people and hundreds of school children have visited the Ballast Garden in Bristol Harbour; Nick Wray gives us a fascinating account of its creation. The records of both hoverflies and plants in flower at New Year also indicate the influence of changes in weather patterns on our natural history, Richard Bland gives us more details of this in both his Phenology and Weather papers. Ray Barnett has also cited weather patterns in his report on Moth populations, with increasing numbers of new species from more southern climes. Ed Drewitt highlights how climate, as well as the usual suspects, intensive farming and pesticide use, have affected populations of Peregrines and other birds of prey. BNS has a long history of distinguished experts in all fields and many were interesting characters. Graham Avery brings us some delightful letters written by JW White about his botanical field trips and Richard Bland reports his discovery of a letter written by Peter Scott describing the visit which lead to the setting up of the Slimbridge Wildfowl Trust. Richard Arthur has given the non-geologists an introduction to the geology of the region, highlighting at the same time a helpful internet resource for visualisation, while Lincoln Garland and Mike Wells ask us to pause and consider the geographical nature of our region as a whole. I hope you enjoy this issue. Thanks to all the contributors and also to the committee for their help and advice. Dee Holladay [email protected] 1 Winter Hoverflies of the Bristol Region Jon Mortin Introduction Hoverflies are members of the Syrphidae family of true flies (Diptera). There are around 283 species currently recorded in the UK (Ball & Morris 2015) although only 166 species have so far been recorded in the Bristol Region. Many people are familiar with at least the more common and colourful hoverflies which can be seen sunbathing or visiting pollen and nectar sources both in the countryside and in gardens. Until recently hoverfly recording was largely carried out by specialised entomologists, but in the last few years many other people have contributed records. Popularisation of this group of insects first began with Stubbs & Falk’s book in 1983 (revised in 2002) but the publication of “Britain’s Hoverflies” in 2013 and the launch of the UK Hoverflies Facebook Group (also in 2013) have both encouraged much wider participation. BRERC also published a guide to the easily identified hoverflies of the Bristol Region in 2011. Many people have gained more confidence in identifying hoverflies by using the available guides and uploading photographs to the Facebook Group and getting identifications (where possible) as well as helpful feedback (including confirmation of correctly identified ones). Winter Hoverflies One consequence of the increased recording of hoverflies in recent years has been a surprising number of records generated in late Autumn and Winter (at a time when entomologists had traditionally put away their nets). It’s not immediately clear whether this trend is due to the extra out-of-season recording effort or to a real change in hoverfly activity, due perhaps to climate change or to the increased availability in winter of both native and non-native flowering plants. Most of the species which tend to be spotted are known to hibernate as adults and can emerge on a sunny winter’s day to sunbathe or feed on any available nectar source. This article summarises (and illustrates) the 14 hoverfly species which have so far been recorded in the Bristol Region from November (although not strictly a winter month) through to February. Records are also included of some hoverflies which could not be identified to species from a photo alone (but of known genus). The winter hoverfly species so far recorded in the Bristol Region (in order of total winter records) are as shown in Table 1. From the table it can be seen that the majority of records (64%) were from November (when temperatures are generally higher) with very few records from January. 2 Winter Hoverflies – Jon Mortin November December January February Total winter Species records records records records records Eristalis tenax 15 5 1 9 30 Episyrphus balteatus 16 4 1 4 25 Melanostoma scalare 10 0 0 0 10 Meliscaeva auricollis 2 1 1 5 9 Eristalis pertinax 6 0 0 1 7 Sphaerophoria sp 4 0 0 0 4 Sphaerophoria scripta 3 0 0 0 3 Syrphus sp 2 1 0 1 4 Syrphus ribesii 1 1 0 0 2 Eupeodes luniger 1 0 0 1 2 Helophilus pendulus 1 0 0 0 1 Baccha elongata 1 0 0 0 1 Platycheirus albimanus 1 0 0 0 1 Meliscaeva cinctella 1 0 0 0 1 Xanthandrus comtus 0 1 0 0 1 Syrphus torvus 1 0 0 0 1 Total 65 13 3 221 102 Table 1: The winter hoverfly species so far recorded in the Bristol Region Year January February November December 1970 0 2 1 1 2006 0 0 0 1 2007 0 1 2 0 2008 0 5 0 0 2009 0 0 0 0 2010 0 0 0 0 2011 0 0 0 2 2012 0 1 2 2 2013 0 0 2 0 2014 0 1 6 2 2015 0 0 1 2 2016 0 4 19 1 2017 0 1 30 1 2018 3 5 N/A N/A Table 2: Dates of records 3 Winter Hoverflies – Jon Mortin Dates of records The earliest records of winter hoverflies on the BRERC database are from 1970. These were all records of Eristalis tenax found hibernating in caves (so not actually on the wing and active). Records of active hoverflies range from 2006 to 2018 with the majority of records from the last few years (see Table 2). From this table it can be seen that hoverfly sightings in the real winter months (December to February) have always been quite rare with no obvious trends. November sightings, however, have increased dramatically in recent years (see graph below). This may reflect mild Novembers in recent years and it would be interesting to see if there is a correlation between local climate and hoverfly sightings. There may also have been an increase in recording activity in recent years. Nectar sources Winter hoverflies are generally spotted in warm sheltered locations especially where pollen and nectar sources are available. Parks, gardens and hedgerows are generally ideal habitats. Ivy is a popular nectar source at this time of year but many other plants are worth checking (if still in flower) such as Hogweed and Yarrow. Ornamental winter-flowering shrubs such as Viburnum tinus and Fatsia japonica are also favoured by many species. Photographic records Not all hoverflies can be identified from photographs but the ones found in the winter months can often be reliably identified provided the right features are visible. Here is a selection of photos to illustrate the appearance of the species referred to in this article. 4 Winter Hoverflies – Jon Mortin Episyrphus balteatus (Marmalade Hoverfly) Eristalis tenax (Drone Fly) on Mexican 28/11/2016 (Bristol) Orange Blossom 07/11/2016 (Bristol) Sphaerophoria scripta Eristalis pertinax on Ivy 03/11/2017 (Bristol) 06/11/2016 (Yatton) Meliscaeva auricollis on Mexican Helophilus pendulus Orange Blossom. 10/11/2016 (Bristol) 06/11/2016 (Yatton) 5 Winter Hoverflies – Jon Mortin Syrphus ribesii Baccha elongata on Hogweed 13/11/2016 (Shirehampton) 22/11/2014 (Severn Beach) Melanostoma scalare on Ivy Meliscaeva cinctella on Fatsia 13/11/2016 (Sea Mills) 11/11/2017 (Bristol) Syrphus torvus on Ivy Eupeodes luniger 07/11/2013 (Sea Mills) 28/11/2016 (Bristol) 6 Winter Hoverflies – Jon Mortin Platycheirus albimanus on Radish Xanthandrus comtus 13/11/2016 (Shirehampton) 06/12/2014 (Bristol) References Ball S.