I have been carrying out bird surveys at the Wildlife Trust’s Lavernock Point nature reserve since 2002, using the British Trust for Ornithology’s Common Bird Census (CBC) method. This means that I have now completed ten survey seasons at the reserve.
I compare the number of territories each species holds on the reserve between years to see if there are any obvious population trends. This enables me to comment on how, or if, the habitat management that has been carried out on the reserve has affected the bird populations. The main habitat management implemented at Lavernock Point has been the cutting of some of the scrub, in order to increase the area of limestone grassland, which is the most important feature of the reserve.
The most significant trend to arise from the surveys has been the disappearance of the Willow Warbler as a breeding bird from Lavernock Point. From having a healthy population on the reserve, this species ceased to hold any territories from 2008 onwards. It’s unlikely that this severe decline can have occurred as a consequence of any change in or loss of breeding habitat caused by the habitat management.
The Willow Warbler breeds in scrub and woodland. Although some scrub has been cleared on the reserve and some of the woodland opened up, there is still plenty of scrub left and most of the woodland hasn’t been touched. Other species that breed in similar habitats, such as the Chiff Chaff and Whitethroat, haven’t experienced a decline.
The reason for the Willow Warbler’s disappearance is probably connected to the wider severe population decline in Wales and England and larger issues, such as pressure during migration and in the winter habitats.
A major reason for me doing these surveys is the simple fact that I love being at Lavernock Point. It’s wonderful to be able to walk through fields full of wild flowers and butterflies and to look out to Flatholm and Steepholm islands and across the channel to Somerset, all while observing the birds of the reserve. It is such a calming, uplifting experience.