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The BTO House Sparrow Questionnaire
Preliminary Results
The BTO House Sparrow
Questionnaire was sent out to all BTO/CJ Garden BirdWatchers and
to any other people interested in contributing their observations
to the survey. Preliminary results from the 11,269 useable returns
have been published as an insert to Bird Table 36, which can be
downloaded as a PDF from the following link.
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The House Sparrow
Questionnaire was divided into sections covering the various factors
implicated in the decline of House Sparrows within urban and suburban
habitats. Analyses carried out on the responses to questions within
each of these sections revealed some interesting patterns.
Section
One: Buildings
House Sparrows were more likely to occur at sites where there were
gaps in the roof tiles. Modern tile designs do not have these gaps
and House Sparrow nest sites may be lost where re-roofing takes
place. Just over 25% of respondents reported that they had had such
gaps blocked, many within the last ten years, and 7% within the
last year. The addition of loft insulation (90% of lofts were known
to be insulated) may also influence House Sparrows).
Section Two:
Gardens
Features within individual gardens were found to have little effect
on whether or not House Sparrows were present in a garden, suggesting
perhaps that it is the wider environment that will ultimately determine
the presence or absence of House Sparrows. However, House Sparrows
were more likely to be reported from suburban and urban gardens
than rural ones, something that matches our understanding derived
from other BTO surveys. Not surprisingly, House Sparrows were more
likely to occur at those sites where food was provided year-round
than at those where feeding only took place occasionally or not
at all.
Section Three:
The wider landscape
Some 16 variables describing the landscape outside a garden (such
as the presence of allotments, arable land, schools, parks and wasteground)
were significantly associated with the presence of House Sparrows
in gardens. In broad terms, these associations suggest that House
Sparrows occur with higher frequency where sites are close to farmland
or where they are close to suburban features such as schools, parks
or wasteground.
Section Four:
Predators, competitors and mortality
There were a number of significant associations with other species,
most of which were related to the habitat preferences of House Sparrows
and the other species with which they were associated. It is interesting
to note that House Sparrows were more likely to occur at those sites
where Sparrowhawks were present, possibly suggesting that predation
by these avian predators may not be important. Dead or dying House
Sparrows were recorded at 6% of sites where this part of the questionnaire
had been completed. The likelihood of finding a dead sparrow was
similar across rural, suburban and urban gardens but there was an
interesting association between dead sparrows and the volume of
traffic recorded outside the house, with dead sparrows more likely
to be found at sites near busier roads.
Before we can say for
certain what factors are behind the House Sparrow decline, we will
also need to examine the results from the intensive fieldwork being
carried out in our 1,500 House Sparrow Project survey squares.
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