Thursday, 6 June 2013

Landing pad for Little Bitterns

Jig jig jag jag, ping ping, boom, woof....woof....woof”.  Singing Reed Warblers everywhere, Bearded Tits feeding young and I can hear six booming Bitterns around me.  A Great White Egret flies by and a hidden Garganey rattles from a nearby reedy pool.  As it gets dark a Spotted Crake whips from the ditch next to the path.  Where am I?  Another foreign jaunt?  No, in deepest England on a wetland that didn't exist 20 years ago.  Woof....woof....woof, Oh, did I mention the singing Little Bittern.

Where wetland colonists are concerned, a recent study has shown that the six species that have established populations in the UK since 1960 all started to breed in protected areas.  Furthermore we know that larger sites are more likely to attract colonising species.  Such areas have been described as ‘landing pads’ for colonising species, allowing them to become established before viable populations spread out.  Ham Wall (and the wider Avalon Marshes in which it sits) is living proof of this as we hopefully see the first stages of Little Bittern establishing a regular population in the UK. 
Climate change analysis predicts that Little Bittern may colonise southern England. Although populations on the continent declined sharply over recent decades, the cause of which is considered to be drought conditions in the wintering areas, some recovery has been evident in the last ten years.  The Ham Wall birds returned this year as usual in early May and feeding flights will hopefully be evident soon.  The Avalon Marshes ‘heron hot spot’ is rapidly taking over from Suffolk as the key area for (Great) Bitterns in the UK, with 35 boomers this year.  At Ham Wall there are 12 boomers with at least 5 nests pinpointed so far from feeding flights.  

Previously I had looked at the developing reedbed ‘rejuvenation’ area, which as predicted, attracted good numbers of waterfowl in its early flooded phase.  A singing Pied-billed Grebe, along with Ferruginous Duck and Ring-necked Duck, were the highlights.   There were still plenty of duck on show during my visit – Pochard, Tufted, Shoveler, Wigeon and a couple of Garganey - but high water has pushed any waders to the margins.  Just a dozen Black-tailed Godwits, a few Redshank and a Whimbrel were visible.  However, as water levels drop by late summer, the area should increasingly attract a good range of autumn passage waders and waterbirds.

below: rejuvenation area and reed-nesting Grey Herons

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