Breckland Birder

Breckland Birder
Crossbill in Breckland, Norfolk Photo by Paul Newport

Monday, 18 March 2013

The Cetti’s Warbler at Thompson Water, Norfolk

With the expansion of its range from its original foothold in the Norfolk Broads in 1974, it was inevitable that Cetti’s Warbler would one day reach Thompson Water.  I always suspected that this would happen one day and then, in March 2007, I received a telephone call from Ian Cook who told me he heard a strange bird song at Thompson Water whilst he was fishing. Having got him to describe the song my thoughts were of Cetti’s Warbler.
Later that day, I visited Thompson Water and suspicions were confirmed when I both heard and saw Cetti’s Warbler close to on the raised bank.  Further visits to this site saw a continuation of observations of the bird along with song being heard, however, these visits were rewarded in spring of 2007 when I saw both male and female Cetti’s Warbler moving through undergrowth close to with the female carrying nesting material.
The male Cetti’s Warbler continued to sing and unusually he was often seen on exposed perches.  Previous searches of this species at other sites have been difficult; however, my first superb views of this often secretive bird occurred on my home patch.
Between the arrival date of Cetti’s Warbler at Thompson Water and the to the time of writing (March 2013), I have counted a maximum of 5 singing birds around the water (summer 2012), this is an excellent increase in numbers of territories, it also demonstrates the resilience of Cetti’s Warbler given that we have had two severe winters since that pioneer bird of 2007.  Song is not only confined to the breeding season, given that this species is resident, it can also be heard giving its loud burst of song even on the coldest, murkiest days of winter.
The habitat around the periphery of Thompson Water is very much suited to Cetti’s Warbler with dense reed-beds and swampy tangled Willow scrub for cover and breeding. 
Due to its secretive nature it is more likely that visitors to Thompson Water will hear this enigmatic Warbler giving its explosive song from the dense cover around the water, however, if you do see a Warbler species in a thicket with warm red-brown upperparts and a broad, often cocked tail, it is likely to be a Cetti’s Warbler and if it sings, I can guarantee that you will be surprised by the volume of the song for the size of the bird.


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