Changes in farming practices blamed for fall in house sparrow population
Sparrow populations in Britain are in sharp decline as a result of changes in farming practices, according to a new study. Localised "extinctions" are clearing the birds from many areas with an 80 per cent decline noted in one breeding population.
Details of the study are published this morning in Nature and the authors from the University of Oxford blame agricultural intensification for the decline. Changes in practices have reduced the availability of winter food supplies for the house sparrow, Passer domesticus, which lives in restricted groups around farmyards.
"Key changes resulting from agricultural intensification that are likely to have reduced winter food supplies for house sparrows in recent decades are the switch from spring sowing of cereals to autumn and an increase in bird-proof storage of grain and other animal feed stocks," the authors report.
The findings are nothing new and are happening for many birds, according to Mr Oran O'Sullivan, general manager of Bird Watch Ireland. "It is quite a common feature across Europe with farmland species," he said yesterday.
"Farmland bird populations have declined dramatically across the EU between 1968 and 1995 with for instance, skylarks declining by 60 per cent and tree sparrows by 83 per cent. The importance of agricultural habitats for birds in Ireland cannot be underestimated. Of 18 red listed (endangered) species in Ireland, more than 50 per cent depend on agricultural habitats."
House sparrows are also in decline here in rural and urban settings, he said. The UK group was studying a population in Oxfordshire that had been monitored since 1971 and similar statistics are not available here. Five years of survey work however does show that house sparrow populations were less frequent than might be expected, Mr O'Sullivan added.
His group with Duchás divides the State into one-kilometre squares and notes the species found in each square as a way to monitor populations. "The house sparrow is recorded in only 40 per cent of survey squares. That isn't great," he said. "There is also a downward trend in gardens. The urban areas have done badly too."
He does not condemn farmers for making changes on their farms, given that many arose as a result of our membership of the EU. "With the CAP (Common Agricultural Policy) and entry to the EU everything changed, we were more efficient with our agriculture."
Hedgerows were lost, fields enlarged and planting cycles changed. The corncrake, once widespread across Ireland, declined rapidly because of a switch from hay to silage. Earlier silage cutting has almost wiped out the corncrake, which now only occupies a few locations including the River Shannon Callows, Mr O'Sullivan said.