BTO/Nottinghamshire Birdwatchers Atlas Update

Lynda Milner & David Parkin

Tetrad Maps

Members will remember that the BTO (in collaboration with the Scottish Ornithologists’ Club and Birdwatch Ireland) is organising the third ‘Atlas’ survey of the birds of Great Britain and Ireland. This exercise differs from previous projects in that it combines both summer and winter fieldwork, so that we have a picture of the breeding and wintering populations. The fieldwork is projected to last from 2008-2012, to include four full seasons. Summer surveys are undertaken from April to July; winter surveys from November to February. Recording is based upon ‘tetrads’: patches of land extending 2Km by 2Km of the National Grid.

Many members have expressed the wish to see a new county bird book; that edited by Austen Dobbs was published forty years ago, and is now well out of date. We decided to use the results from the Atlas survey as the basis for this book. If we could visit every single tetrad within the county during the four year period, this would give us the first comprehensive overview of the distribution and abundance of Nottinghamshire’s birds. In addition to telling us where the birds are, the results would also identify any ‘hot-spots’ that need protection. Planning authorities now recognise the importance of Sites of Importance for Nature Conservation (SINCs) and will extend protection to these within their jurisdictions. In order to give these sites protection, we need to have good, clear, objective data about their wildlife, and the Atlas results will provide just that. So, the Atlas is important for more than just mapping the region’s birds.

There are two components to the fieldwork: Timed visits and ‘Roving’ records. Timed visits last for two hours, with one visit in each of November/December, January/February (for winter birds) and April/May, June/July (for breeding birds). During each visit, every bird is counted and totalled for each hour separately, to give four counts for the winter and four for the summer seasons. These can be used to give the average number of birds seen per hour in winter and summer, and comparisons of sites will show the relative abundance of each species across the county. They will be used to produce ‘density maps’ for the common species. In addition to these timed visits, ‘roving’ or casual records can be included. These are birds seen at other times (by anybody), and are especially important for the less common birds that can be missed during a timed visit: Willow Tits, Lesser-spotted Woodpeckers, Waxwings, Water Rails, etc.

Field work started in November 2007, so the first winter and summer are now behind us. It is time to take stock of the situation and see where we are. There are 550 tetrads in Nottinghamshire, and each of these has to be visited if we are to complete the survey. During the first winter, 175 of these received the necessary two timed visits. At the time of writing, counts have been returned for two summer visits from 106 tetrads, with single counts from a further 20 (hopefully, the results from the second visits will be entered soon!). Although this total of 126 tetrads may seem lower than the winter results, several recorders do not enter the data ‘on line’, preferring to send paper copies to the BTO for data entry. We anticipate about 30 of these, so the summer cover will be fairly similar.

This means that about one third of the county has already been counted: an excellent start! However (and there is always a ‘however’!), there is still two-thirds of the county to be surveyed. Fieldwork for timed visits is pretty easy. First, you have to accept that you are committing yourself to making four visits to a site, each lasting for two hours. Then, you choose a tetrad. If you are comfortable with using the web, you can find the unallocated tetrads on the BTO Atlas website. Alternatively, you can phone Lynda Milner (the BTO Representative for Notts) and she can help you choose your tetrad. Then you look at the map and decide upon your route. Most tetrads in Notts can be visited without straying into private land, but I have found that all the land-owners that I have approached have been content to allow me onto their property when I have explained the reasons for my visit (some have asked me to tell them if I found anything interesting — Buzzards, Goldfinches, Kingfishers, etc.). You then choose a nice day, turn up fairly early and walk round counting birds. It’s a bit like ‘day-listing’, only it’s ‘hour-listing’. I find it more efficient to do two tetrads in a morning. Choose two that are adjacent; spend an hour counting the first, move into the second for two hours, and then back into the first again, ending up where I started to get back into the car. The two hours do not have to be back-to-back, although they should be on the same day. The summer and winter visits do not have to be in the same twelve-month, though each of the winter visits should be in the same winter, and each of the summer visits should be in the same summer. When the four visits have been made, timed surveying for that tetrad is finished. It is not (thank goodness!) necessary to visit each tetrad every year!

So far, I have only dealt with ‘timed’ visits. Roving records are equally important. I realise from my own experience that I have missed birds that I know occur in the tetrad: Tree Creepers and Tawny Owls are typical examples. I cannot stress the importance of members submitting observations of any birds any where! When we come to produce the maps of the county’s birds, every record will be important. When the book is published, a member may come along and grumble that ‘we’ missed Tree Creeper or Marsh Tit or whatever from tetrad X when he sees them there regularly. If he has not submitted his records, my guess is that the response will be dusty (from Lynda) or more forthright (from me): if you don’t tell us your records, we will not know about them, and they won’t go into the Atlas! Believe me, EVERY RECORD COUNTS!

We will be producing maps from time to time to show how the work is proceeding. Paper copies of the Bulletin do not permit colour reproduction, so the difference between possible, probable and confirmed breeding may not be easily seen; however, colour maps are available on the Notts Birders website.

Tetrad Maps

I have provided some maps of Notts showing results so far. The first two show the extent of timed visits in winter and summer. It is clear that there is something of a bias towards the south and centre of the county: that’s where most people live. If you live in the north (or are prepared to travel for your tetrads), there are plenty of good sites still available.

Tetrads surveyed in winter: yellow=early only; white=late only; black=both periods	Tetrads surveyed in breeding season: yellow=early only; white=late only; black=both periods

The two maps below show the distribution of Wrens across Nottinghamshire. This bird is likely to be recorded from every single tetrad in the county. If you know of records from ‘blank’ squares — let us know.

Wren winter distribution: red=present breeding	Wren breeding distribution white=no evidence; yellow=possible; orange=probable; red=confirmed breeding

Another widely distributed species is the House Sparrow, although this is one that has declined in recent years. It is important that we get a clear idea of where this familiar bird can still be commonly found.

House Sparrow winter distribution: red=present	House Sparrow breeding distribution: white=no evidence; yellow=possible; orange=probable; red=confirmed breeding

At the time of the first Atlas in the 1960s, Skylark was one of the most widespread birds in GB&I. Changes in agriculture and land-management have seen a marked decline across the islands, and here in Notts it is also much less common.

Skylark winter distribution: red=present	Skylark breeding distribution: white=no evidence; yellow=possible; orange=probable; red=confirmed breeding

The next maps show the records of two summer visitors: Willow and Sedge Warblers. Already patterns are emerging: Willow Warblers in the more wooded regions and Sedge Warblers in the wetlands and along the main river valleys.

Willow Warbler breeding distribution	Sedge Warbler breeding distribution

One of the harder birds to include in timed visits. Tawny Owls are readily recorded calling en the evening: but timed visits are typically in the mornings. So, evening and night-time records will be essential if we are to get a decent picture of owls, Woodcock, etc.

Tawny Owl winter distribution: red=present	Tawny Owl breeding distribution: white=no evidence; yellow=possible; orange=probable; red=confirmed breeding

Please help with this important project. Please don’t leave it to someone else!

Get more information on the Bird Atlas.

Lynda Milner: lyndamilner@hotmail.com

David Parkin: bluethroat@btinternet.com