Common Starling (Sturnus vulgaris) adult, winter plumage, feeding in farmyard with domestic cattle© FLPA / Gianpiero Ferrari/REX/Shutterstock

Cattle farmers are recommended to starling-proof feeding areas, as research shows the negative effect the birds have on ration composition could equate to £40,000 a winter.

For her University of Nottingham dissertation, Kerensa Hawkey – now a trainee feed formulator at Mole Valley Farmers – last winter monitored the effect of starlings on 10 farms in Cornwall and North Devon with TMR-fed herds varying in size from 200 to 1,000 cows.

Building design and feeding varied across the farms, with some feeding inside and others via outdoor troughs.

Assisted by Professor Phil Garnsworthy, head of animal science at the University of Nottingham, Ms Hawkey assessed the amount of feed stolen by starlings by comparing weight and compositional changes of TMR samples either exposed to the birds or covered to prevent stealing.

See also: Farmer Focus: Invasion of starlings in the calf shed

They found that starlings ate 18-42% of ration samples – with evidence that starlings were picking out the cereal and protein components.

The subsequent loss in energy and protein totalled £0.97 a cow a day, they found, with loss of soya and wheat in a 240-cow herd over 180 days adding up to more than £40,000.

She also recorded a 14% reduction in dry matter concentration from morning to evening, which could equate to a 7.5 litre reduction in yield a cow a day.

Given the proven financial implications of starling infestation, farmers could benefit from assessing the scale of the issue and, if necessary, investing in starling-proofing.

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“Starling-proofing can be recognised in both the mentality of the farmers and changes to the building,” Ms Hawkey told Farmers Weekly.

“By actively closing doors when entering a feeding area, the number of starling entering can be reduced.”

In terms of investment, she recommends:

  • Ensuring corrugations in the roof do not leave gaps big enough for starlings to get through
  • Add wire mesh across any air vents
  • Add rubber flaps along bottom door edges
  • Any gaps in shed are covered – use foam material to fill awkward shapes