Nightjars 2004 Survey

17 July 2005 |

Nightjar © Jerry O'Brien

2004 saw a repeat of the national Nightjar survey, the last one having been carried out by the British Trust for Ornithology in 1992. There was an excellent response from BTO and other volunteers in Berkshire and with the large number of 1km squares needing to be surveyed (98 in total), this was perhaps as well! The large number of survey areas reflects the importance which the Berkshire BTO region now has for this species and nearly all the sites were ones known to have held one or more breeding pairs in recent times, thus most surveyors managed to see or hear at least some of the target species.

Most survey sites were made up of a number of 1km squares which meant that many included territory, or even whole squares, which were quite unsuitable for Nightjars. This was necessary in order to ensure that all the habitat surrounding a central, typically heathland, area was checked. Additionally on the list were a few random 1km squares, included as a kind of control to test the scale of overlooked Nightjar territories within any region. Berkshire had seven such squares, none of which produced any Nightjar records or indeed any likely habitat in most cases which, while disappointing for the surveyor, provided useful reassurance that we were otherwise looking in the right places! Nationally, a number of new Nightjar territories were discovered this way, so it was obviously a worthwhile exercise.

The survey itself was quite easy to do - surveyors were asked to visit all suitable habitat within their allocated area at least twice during the breeding season and record the number of churring males.

The Berkshire results, compared with the last survey of 1992, were remarkable. In the 1992 survey a total of 39 churring males were located whereas in 2004 the comparable area produced 96, although it must be said that our coverage in 2004 was probably more thorough. Very few sites have reduced their Nightjar count since 1992 and only one seems to have lost them totally, which is excellent news. To put this in perspective, part of this apparent increase may have been due to less complete site coverage during the previous survey but there have undoubtedly been substantial increases in many places particularly in the southeast of the county, where the Berkshire BTO region overlaps parts of Surrey and Hampshire. The heathlands between Crowthorne. Bracknell and Camberley and those around Pamber Heath, Padworth and Wokefield Common now hold good numbers of breeding pairs.

Nationally, a total of 4,132 individual males were detected in 2004, which constitutes a 34% increase since 1992 (3,093 males). It would appear from the foregoing that Berkshire has done even better but, given the relatively small sample size and the aforementioned difference in surveyor effort, this may not necessarily be true. However it is probably safe to say that Berkshire numbers have increased by at least a third since 1992. Here is a summary of the Berkshire site counts. It should be noted that some site names are somewhat generic and may include birds from surrounding areas; also, as BTO regions are mapped by 10km grid square, not all records come from within the county of Berkshire

Results of 2004 Nightjar survey
SiteNo. of churring malesCount comparison with 1992
Wickham Heath2Up
Snelsmore Common3Same
Newtown Common1Same
Greenham and Crookham Commons5Down
Bucklebury Common1Down
Tadley Common2Up
Silchester Common4Up
Pamber Forest2Up
Padworth Common5Up
Wokefield Common7Up
Bramshill Plantation16 *See footnote
Gorrick Plantation4Up
Crowthorne/Bracknell heaths (Berkshire section)37Up
Crowthorne/Bracknell heaths (Surrey section)14Up
South Ascot heaths7Up
Windsor Forest2Up

* Figure not used in comparison with 1992 survey due to differences in coverage