Thursday, April 29, 2010

Skylark numbers in SD9627

I completed my BBS early visit yesterday at Blackshaw Head. Among other birds, I saw just a single Skylark which sort of worried me. This prompted me to look back, aided by the BTO website which holds data for all previous years for this square, to see how numbers have moved since 1994 when I undertook my first survey. Having seen the numbers I'd forgotten that in 2008 I only saw 2 Skylarks up there!

The chart here shows Skylark numbers each year and there is a definite downward trend (I still have to add the number from the late visit this year). This is a single 1km square, one observer, twice a year so it isn't statistically significant, but it tells me that I'm seeing fewer Skylarks now than I used to. There have been several small changes to the landscape, such as stable blocks being built and the Pennine Bridleway being improved, but nothing major. My early visit is always done at the end of April so no variation there. The largest step down coincides with the 2001 foot and mouth outbreak.

I'm not sure what this proves, if anything, but I just thought I'd share my concern.

2 comments:

Nick Carter said...

Very useful tool Jeff and shows the value of regular BBS work, I have done my square since 1993 when the pilot work began, will have to look at my figures in the same way. Not looking like i will be able to do an early visit this year, anyone want to take it on?

Jeff Cox said...

If I remember correctly it's only over the hill from me so I can do it if no one else has a burning desire to do so. What date do you usually complete it by Nick?