LINCOLNSHIRE 2017 ROOKERIES SURVEY
HELP WANTED COUNTING ROOK NESTS IN LINCOLNSHIRE THIS MARCH/APRIL
I am looking for as many Lincolnshire birdwatchers as possible to complete the following excel spreadsheet and return to the email address shown.
I will collated the collected data and will submit to BTO and the http://www.rookeries.uk/ website.
DOWNLOAD a recording sheet at http://www.lincsbirdclub.co.uk/Articles ... s_2017.xls
A standardised methodology allows comparisons with past and future surveys. The following methodology has been adopted from that used by national surveys (in 1975, 1980 and 1986) and the last Lincs survey - Lincolnshire Rooks and Rookeries 1980 (completed after Dutch Elm Disease).
The aims of the survey are to;
• Record (and map) the location of as many rookeries in Lincolnshire as possible;
• Count the number of nests in all rookeries surveyed;
• Record other pertinent data, e.g. tree species in which nests are located;
• Provide an estimate of current breeding population for Lincolnshire (and compare with the 1980 survey).
A rookery is defined as any group of nests 100m or more from the next nearest group. Whilst this is an arbitrary definition it has the advantage of being relatively easy to apply in the field and hence repeatable. In some local situations, this may require amendment. A consequence of this definition is that a single rookery may be spread out over a large area or an area with many nests could comprise a number of rookeries.
The difficulties of counting nests in rookeries are well known; the most obvious problems concern the counting of nests in conifers, the counting of multiple nests, the difficulty (in large rookeries) of arriving at a similar total each time, and the inaccuracy that can result from counting nests from a distance.
Rookeries can, of course, be located at any time of year, but it is best to count the nests as late in the season as possible. The best period to count nests in a rookery is between 15th and 30th April as all nests should then be complete and in use, but the trees will not yet be in full leaf obscuring the nests. Counts made earlier in the season will be accepted as a visit may not be possible during the best time. There is no need to differentiate between occupied and unoccupied nests as this can present difficulties and be time consuming, but should this be recorded, please include a note. Generally, a single nest in an isolated tree is likely to be that of a Carrion Crow, but single Rook nests can occur and should be recorded as a rookery. Where it is impossible to get an accurate nest count, e.g. where nests are in conifers, please make an estimate of number of nests. Where possible, please record the tree species in which nests are built. Not all nests in a single rookery will necessarily be in the same tree species. Such data may prove useful when trying to assess the impact of various tree diseases, e.g. ash dieback fungus, on nesting Rooks.
Surveyors are asked to record the following for each rookery:
Rookery name;
the six-figure national grid reference (NGR);
date of count;
number of nests;
number of nests in each species of tree used.
Based on instructions produced by Ben Carpenter for the Oxfordshire Rookery Survey 2013 and 2014
Need help obtaining a six-figure national grid reference (NGR) – then use http://www.bnhs.co.uk/focuson/grabagrid ... /index.htm
Any questions, please email andrew@forktail.co.uk
Rook with pine cone - taken by Roger Bark Nov 2012