You only have to compare this summer with last to realise how much
things can change from one year to the next, both in terms of the weather and
its effects on birds and other wildlife. Short term differences in bird populations
and their breeding success are of interest to those studying such things but it
is the longer term changes that are of wider interest. In the case of birds,
information on how well the populations of many of our breeding species are
doing comes from the BTO/JNCC/RSPB Breeding Bird Survey (BBS), the latest
report from which has just been published.
As a volunteer myself, I appreciate the tremendous value of the survey
and the importance of the information collected by the 2,592 volunteers who
participate in BBS. Participation is simple enough, involving two visits to a
survey square and the recording of what birds are seen and heard, and in what
numbers. The survey, which began in 1995 as a replacement for the Common Birds
Census operated by BTO, provides a measure of population change for a wide
suite of species, highlighting those that have shown significant increases or
decreases in their populations over time.
The latest report highlights the continued decline of turtle dove (down
by 85% since 1995), cuckoo (down 50%), spotted flycatcher (down 49%) and
starling (down 53%), among many others. Some species are, in contrast,
increasing. These include: goldfinch (up 109%), blackcap (up 133%), nuthatch
(up 88%) and great spotted woodpecker (up 139%). Not all of the increases are
welcome, however, with Canada goose, greylag goose, ring-necked parakeet and
red-legged partridge all showing sizeable increases in their populations.
One of the great strengths of the survey is that the information can be
viewed at the regional level, something that has revealed some fascinating
differences in how species have been doing. Cuckoo is one of several species in
which populations in England are in decline but those in Scotland are stable or
even increasing. There are a number of possible reasons why this might be
happening, one of which is related to a changing climate, but more work is
needed to be certain of what is going. Fortunately, the efforts of us
volunteers provide the information needed to support this work.
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