The BTO atlas, breeding and winter seasons, 2007-2011

Harry Green

BTO Regional Representative Worcestershire. Tel: 01386 710377 or email

The collection of data for this Atlas is now into the last winter. Next summer (2011) is the last breeding season for recording. For Worcestershire the recording effort has been good but there are still gaps to fill. Please help to plug the gaps.

As a reminder, the atlas records are collected for the Breeding season (beginning April to end July) and winter season (beginning November to end February) in two ways. Roving Records are literally observations made anywhere and the main aim is to build a complete list of species in each 10x10 km square of the National Grid for both winter and summer. Timed Tetrad Visits (TTVs) are recording visits to 2x2 km squares within a 10x10 km square, according to the standard grid, and counting the birds seen during either a one hour or a two hour visit. The TTVs entail two visits to each tetrad in winter (early November & December, late January & February) and two in summer (early April & May, late June & July). These records are of course added to the 10x10 km species list but they also enable BTO to make population estimates for each species. The aim is to cover all 450 tetrads in BTO Worcestershire if possible, both winter and summer.

In addition, observers are encouraged to make evening or nocturnal visits in the breeding season to records owls, nightingales, water rails and maybe nightjars and quail)

Observers can submit records either on paper forms or on the Atlas web site ( The use of the internet is making this an outstandingly efficient project as it is easy to submit records through the web site so they go directly on to the database. Paper records are still of course essential and valuable but these take longer to be entered. The web site also shows which tetrads are not surveyed and enables an observer to select those they would like to survey. As Regional Representative this information is sent to me so I can allocate the tetrads and confirm this with the observer. If you would like to take part and would like to discuss possibilities please contact me especially if you are not an internet user. I can supply paper forms and allocate tetrads.

The absolute minimal number of TTVs required per 10x10km square in eight. However the more that can be covered the better. In several of our neighbouring counties (Shropshire, Herefordshire, Gloucestershire) the aim is cover every tetrad and to produce a local tetrad atlas of wintering and breeding birds. Although an atlas is not being produced for Worcestershire we have now covered a great many tetrads so complete coverage becomes a goal to aim for! The simplest way to see which tetrads are not covered is at the web site where you can volunteer to fill a gap!

For the summer (breeding) recording the highest possible evidence of breeding is an important aim. The categories are of course to do with nesting e.g. nests with eggs or young, or the sight of an adult carrying food to a nest or carrying faecal sacs away, or seeing an adult enter or leave a nest or nest site, or the sight of freshly fledged young. This evidence is required for each species in each 10x10km square.

The final aim to record the maximum number of species (all that occur) winter and summer so the atlas can give a true picture of distribution. One good way to check what has been recorded and what may be missing is to visit the web site.

Evidence of breeding owls is particularly important as records are scarce.

If you are or want to become a BirdTrack user please join that system! The records from BirdTrack are incorporated into the atlas database. BirdTrack gives a useful way of keeping your own records (you can always access them) and also making them useful for other surveys. If you visit a site regularly please consider joining BirdTrack – visit the Atlas or simply the BTO web site for further information.

Also never assume somebody must have put a record in so you don’t need to bother. Some of our keenest bird watchers of the twitching fraternity don’t contribute to the Atlas – many do of course – b ut it would be a great shame if Worcestershire’s Lapland Buntings and all these waxwings did not get recorded.

Finally, if you have an interesting record for the Atlas and you don’t want to be bothered with the web or paperwork please give me a ring and I’ll make sure your record is used.

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