Tiny bird - the firecrest - thriving in woodland areas of the East, says new report

The firecrest, which normally prefers life in Continental Europe, is becoming more common in woodland areas in Norfolk, say authors of the latest Rare Breeding Birds Panel (RBBP).

The tiny colourful bird first colonised the UK half a century ago, but the population has risen, and the latest reports suggests there may be over 1,000 pairs nesting in Britain. At least 116 of these nest in Norfolk, the majority of which are found in Thetford Forest.

Four firecrests weigh less than an ounce and the bird competes with the goldcrest for the title of Britain's smallest bird.

In 2010, the latest year to be covered by the RBBP report, there were reports of at least 800 pairs of the tiny woodland bird. But experts believe there could be well in excess of 1,000 pairs now nesting in the UK, all in England and Wales, because of its resemblance to the goldcrest.

The warmer summers seen in recent decades favour the firecrest, and during the winter it leaves its nesting sites to winter along the coast of South West England or on Continental Europe.

However, the RBBP report paints a bleak picture for the Dartford warbler, which appears to have declined substantially in the last few years, because of the harsh winters leading up to 2010.

The report shows that in some parts of its range, the robin-sized warbler has suffered particularly badly. In Suffolk, the population dropped to only 91 pairs from 135 pairs in 2009.

Ben McFarland, area manager for the RSPB on the Suffolk Coast said authorities had been working to reverse the decline of the Dartford warbler by regenerating and improving its favourite heathland habitats.

'Historically, the rapid increases in the numbers of Dartford warblers may have been partly due to some of the milder winters we've experienced, because the Dartford warbler stays put on the breeding grounds all year-round. Hopefully the winter of 2012 may have allowed the birds to recover, but it's safe to say that the changing climate is having a significant impact on the future of this species,' he said.

Other notable events featured in the RBBP report include suggest that the golden oriole – a striking thrush-sized yellow-and-black bird – did not nest in the UK in 2010 and the purple heron and pink-footed goose were both recorded as nesting for the first time.

Mark Holling, secretary of the RBBP, said: 'These shifts shown by some nesting birds fit the pattern of climate change with species moving from further south in Europe to colonise the UK.'