Sunday, 9 December 2012

BTO Conference continued...


As a carry on from the last blog concerning the annual BTO week-end conference, the auk colonies have been extensively studied on the Isle of May.  During the worst years when Guillemots in particular were suffering from a lack of food, the social fabric of the colonies effectively broke down with many chicks being left unattended for long periods.  Although there was subsequently some increased predation from gulls, the social breakdown was so severe that adult Guillemots were killing chicks and even tossing them off the cliff!  Not surprisingly the survival rate was extremely low and it is thought that only the very earliest hatched youngsters had any chance of surviving during these very lean years.

Guillemots and Razorbills apparently moult just after the breeding season and become flightless for a short period.  Geolocaters indicate that they spend this time east of Scotland and drift south down the east coast of England during this time.  Puffins however spend their time off the north of Scotland and even go right the way around Scotland and Ireland to winter on the Atlantic seaboard off south west England and Ireland.

The current state of affairs on this seabird city island was summarised as follows:-
  • slight recovery since the crisis of the mid 2000s
  • may be associated with colder winters
  • however it is predicted temperatures will rise again and food webs will change too
  • effects likely will vary regionally
  • offshore renewable energy will represent a threat and significant losses anticipated
A further atlas input titled 'Joining the dots' provided some worrying trends, most of which are already well-known.  This included contracted ranges for 24 out of 28 farmland birds and 15 species have seen populations tumble, all during the period 1970 - 1990.  Other birds of concern include the Short-eared Owl which has suffered a 35% reduction in numbers during the last couple of decades and the Hawfinch has suffered a significant range reduction.

A major outcome of the survey is that it provides the BTO and its partners with the knowledge of where birds are and some idea of their density.  This comes in to its own when assessing the impact of man on the environment, and Windfarm Sensitivity Maps have been created which can be assessed by would-be developers so that future conflict can be avoided.  Just round the corner, the European Bird Atlas is due to start next year, and it is thought that the results of the British and Irish 2007 - 11 atlas will be incorporated within it.

Another couple of presentations championed the use of Birdtrack and other reporting mechanisms such as Breeding Bird Surveys and National Garden Watch not only to report birds but other taxa too.  Examples include butterflies, dragonflies, mammals and amphibians, and in some cases these systems provide more records than specific taxa disciplines or organisations.  Invertebrates are important barometers and it is assessed that global warming means that many are on the march north and colonising, at a rate which averages out at five metres a day!  Small wonder that we see new species of grasshoppers and bush-crickets in the county these days!  In essence the message was that birdwatchers make a very valuable contribution providing they submit their records, and this is further enhanced through team-working and the collaboration of all the scientific and conservation organisations.


Neil M

Post a Comment