By the BTO
It’s been a mixed year for sparrowhawks. British Trust for Ornithology’s (BTO) Garden BirdWatch survey tallied its highest recorded average counts in gardens last January, followed by the lowest-ever numbers for December.
Sparrowhawks are most frequently seen in gardens during the autumn and winter months. It is a time when numbers are swelled with juveniles, and when the smaller birds they prey on are flocking into gardens to feed.
January 2016 saw the highest average counts of sparrowhawk for the time of year but since last summer numbers have been abnormally low, according to Garden BirdWatch. They were only seen in 8% of gardens in December, well below their average and a 5% reduction on the year before.
The BTO suspects that this decline is linked to the wet weather in June, which resulted in a poor breeding season for many smaller birds such as blue tits and great tits, on which the sparrowhawks feed. With fewer young birds around there would have been less available food to feed their own chicks, potentially leading to lower survival in young sparrowhawks. They may also have been directly affected by the wet weather.
Sparrowhawks are not always popular garden visitors, as they feed on other garden birds. Their population crashed in the 1950s and 1960s due to pesticide poisoning, but numbers have since recovered. They are the bird of prey most commonly seen in gardens. The BTO does not yet know whether this sudden Sparrowhawk decline will be a continuing trend.
Claire Boothby, BTO’s Garden BirdWatch Development Officer said, “The surprise appearance of a sparrowhawk is always a dramatic garden event but one that has been witnessed by fewer people than usual this winter. Sparrowhawks rely on the availability of prey, in their case particularly small birds, to survive. A poor breeding season may have had an effect on the number of sparrowhawks seen in gardens.”
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