Preliminary Findings

Before setting up the CTBSG, it has been necessary to get the correct permission to access Cabot Tower early enough in the day to make it worth while, as most movements of the types of birds we will be monitoring take place before the tower is open to the public.

After gaining access, a few trial sessions have taken place, with mixed results.

On Friday the 23rd of September things were looking promising with lots of movements of gulls down the Avon into Bristol, a couple of peregrines, a few cormorant, a large conspiracy of 21 ravens grouped tightly together just overhead, and movements south of 62 meadow pipits, 20 grey wagtails and 5 pied wagtails. The session lasted c2 hrs from 6:45 , winds were light with few gusts (SW 10 – 18mph), it was bright and clear with temperatures of 14°C.

For the second preliminary session on Sunday the 25th, I was joined by Ed Drewitt. After being greeted with a grey heron and a peregrine we registered no movement of any passerines apart from perhaps a couple of grey wags that we heard passing over. We were up there for c1.5 hrs, again from 6:45, winds were more gusty (S 12 – 21 mph), grey with drizzle and temps of 15/16°C.

These results perfectly illustrate the nature of bird migration and its unpredictability. Within the space of 2 days, significantly different results with conditions not too dissimilar. The most likely explanation for the lack of movement on the Sunday, was that the weather had turned after a particularly mild day on Saturday with light winds and plenty of sun. Hirundines were definitely making the most of the Saturday’s conditions, with c1k moving south down the Avon Gorge.

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Birds over Bristol…

Brandon Hill is one of the best places in Bristol to see urban birds and wildlife. The hill is alive with activity all year round, but Spring and Autumn are the best times to see raptors and passage migrants, with sightings of peregrine, sparrowhawk and buzzard on a daily basis and migrant passerines constantly moving through.

This video is of Clifton’s urban peregrine falcons. The first 2 clips are views from Cabot Tower, looking out to the Wills Memorial Tower at the top of Park Street and the spire of Clifton Catholic Cathedral on Pembroke road.

Brandon Hill has a large variety of resident songbirds, with nesting blackcaps and goldcrests, many passage migrants like redstarts, willow warblers, garden warblers and the occasional kingfisher that stop for short periods and seasonal visitors like overwintering redwings.

Cabot Tower has recently reopened to the public, which has given a new perspective from which to view Bristol’s bird life. Since reopening this summer, it has provided unique opportunities to monitor Bristol’s urban peregrines – from Clifton Village down to the City Centre, and so far this autumn, it has delivered some exciting sightings of passage migrants that would have been missed from ground level.

The reason for the formation of the Cabot Tower Bird Study Group is to monitor this visible migration over Bristol, and submit valuable data to the BTO about bird movements over cities. We will also be comparing data with the Tower 42 Bird Study Group in central London.

After movements of willow warbler, garden warbler and chiffchaff in the last few weeks, wagtails and pipits are now starting to pass over regularly. Perhaps skylark next, some Scandi thrushes, siskins or maybe some woodies in October..?

Background…

CABOT TOWER BIRD STUDY GROUP

The Cabot Tower Bird Study Group is a visible migration study and raptor watch that meets *weekly at the top of Cabot Tower during the spring and autumn migration periods, to collectively scan the skies over Bristol for passage migrants and birds of prey.

It is an extension of a wider UK urban migration study, that began in London at the top of Tower 42 in the autumn of 2009. Data collected will be collated with the established Tower 42 Bird Study Group , conceived and run by David Lindo (The Urban Birder), which regularly contributes valuable migration data to the BTO via BirdTrack.

View over central London and Canary Wharf from Tower 42, just before sunrise

Urban visible migration watch with David Lindo – Tower 42, London UK – Autumn 2010

The aim of the initial sessions during the late autumn of 2011 will be to monitor numbers of passage migrants and arriving winter visitors, to monitor Bristol’s urban peregrine and buzzard population and to look out for passing raptors rarer to Bristol (red kite, goshawk, osprey?….).

The group has permission to access Cabot Tower before sunrise (when public access is allowed) and is open to anyone with an interest in birds or wildlife who would like to be involved.

View over Clifton from Cabot Tower, including regular peregrine roosts: the Wills Memorial Tower towards the right, Castlemead to the extreme right and the spires of Clifton Cathedral and Christchurch on the horizon to the left – click for larger image

View from the Wills Tower of Cabot Tower and Brandon Hill – a green oasis in urban Bristol and a regular sojourn for passing migrants

This autumn, we will initially only have space for c.10 people in the group, including birding / photographic equipment. Numbers may be re-evaluated before spring 2012.

For more information, please comment below and I will add your email to the mailing list.

*frequency of watches may be increased during conditions propitious for migration.

THE IMPORTANCE OF URBAN WILDLIFE STUDY

Urban wildlife studies are becoming increasingly important. Around 90% of the UK population now live in urban centres and that figure is on the increase. With the development and spread of towns and cities, there is an increasing amount of urban habitat, which often results in decreased biodiversity and the suffering of native flora and fauna, unable to adapt to a rapidly changing environment.

Understanding how wildlife is effected by human development through research is the best way of learning how best to manage future development to reduce the detrimental effects it has on our native species.

Studying urban wildlife and managing urban habitat to encourage its spread are also important in getting the urban population interested and involved in nature and conservation. Of the 90% that now lead an urban lifestyle, only a small percentage have more than a passing interest in wildlife and natural history, and of those with an interest, most are likely to visit rural locations to enjoy their birding and wildlife-watching. Understandably, this is because rural locations often present much better opportunities to see wildlife in its natural habitat. This is also why scientific studies of British wildlife have traditionally been undertaken in rural habitats – with the conservation of rarer and more exotic species often high on the agenda. However, the majority of city dwellers are not particularly interested in nature and conservation, as it isn’t a big part of their everyday lives and it is not immediately obvious why it should concern them. Not surprising then that they are not likely to lend their support to an initiative to save wrynecks or nightjars for example, when they are unlikely to have ever heard of them. Organisations and societies whose raisons d’être are to conserve UK wildlife are now waking up to this and have realised that if they want to get the support of the masses, they must first get them interested and enthusiastic about local and accessible wildlife and conservation issues that are relevant to them.

Managing urban habitats to encourage wildlife back into cities, and dedicating time to the study of naturally occurring urban wildlife is the first step. Making the public aware of the richness of the urban nature that surrounds and is relevant to them is the next step. By making people aware of and excited about their local wildlife and encouraging them to share in the enjoyment of it has the positive effect of making them care more about it – and if people know what something is, a bit about it and most importantly where they can see it, then they are much more likely to want to protect it.

Increased engagement between people and wildlife in towns and cities, and increased understanding of the wider issues that effect the wildlife that is relevant to them, builds a respect and appreciation of the natural world, which in turn encourages increased support for other issues, including rural conservation.

The Tower 42 bird study group in central London is more than a testament to this. The group meet weekly during the spring and autumn migration periods atop the roof of one of London’s tallest skyscrapers – Tower 42 in the centre of the City of London. T42 is possibly the most urban location in the UK, and is in all likelihood the last location anyone interested in the study and spectacle of visible migration would choose to set up a watch. But this is precisely why it is important. Their findings (recently including sightings of little egrets, migrant meadow pipits, soaring buzzards, sparrowhawks, peregrine falcons and historical sightings of honey buzzard and red kite) are helping to build up a clearer picture of exactly how the spread of the urban environment is effecting the behaviour of our native species, whilst at the same time inspiring urbanites to expect the unexpected when it comes to urban wildlife, even in the most unlikely of places.

BRISTOL

Bristol is the largest city in the south-west of England and like London, is not exactly considered a migration hot-spot. However, it does get its fair share of passage migrants and occasional rarities. It consists of a mixture of habitats, including mixed woodland, parkland, grassland, farmland, hedgerows, rivers, streams, canals, standing open waters and small ridges and valleys within its larger urban zone. Notable features are the River Avon, which runs through the heart of the city, down the Avon Gorge and into the Severn Estuary. Bristol is also surrounded by all kinds of zoogeographical regions, with large oak woods and moorland in nearby Devon and Wales to the west, the Severn Estuary, Wye Valley, Forest of Dean and Slimbridge WWT to the north, the extensive farmland of the Cotswolds to the east, Chew Valley and Blagdon Lakes and the Somerset Levels to the south, and further south, the Mendips and upland heaths of the Blackdown Hills and Quantocks. It is also far west enough to pick up the occasional migrant moving south-east into Britain from Canada or Greenland before making the journey south to the continent and Africa.

CABOT TOWER

Cabot Tower has unimpeded 360º views across the city and is the best vantage point in Bristol to view urban visible migration.

Setting up the CTBSG has only been possible with the help of David Lindo and Ed Drewitt, and the support of the BOC and the Avon Wildlife Trust.

Sam Hobson