Friday, 1 June 2012

CSI: South Marsh East

Currently the marshes should be alive with dozens of chicks from the record numbers of black-headed gulls breeding there.  However a visit on Tuesday and everything appeared ominously quiet on the two gravel islands.  Donning the waders a visit was made and the scene of a mass murder uncovered:

In total thirty four black-headed gull nests and broods were lost, along with between two and three common tern nests.  Only one adult appeared as a casualty - seemingly died of fright and undamaged:

A further two nests appeared to have been abandoned with the eggs still in:

The perpetrator was a mystery.  The islands are protected by a deep and wide fox trench around the perimeter and thoughts were turning to otters which have been observed taking nestlings last year.  However the return trip revealed tell tale prints on the island in front of the hide:

That of fox.  Whilst they are giving great photographs at Watton on Flickr there is no hiding the nature of the beast; that said they cannot be blamed for what comes naturally.  Some would say the expanding gull colony (243 birds counted in April) needed thinning out.  Unfortunately 2X18's young were amongst the casualties.  The terns were unfortunate but it is early enough in the year for them to try again - and already they have moved onto the new tern rafts at Watton with at least three pairs now present - thanks to Tony McLean for this picture:
There are also terns nesting elsewhere on South Marsh East and South Marsh West too - so all is not lost:
The massacre is attributable to the dry spring; because of the low levels in the marsh all birds including the avocets were nesting close to water line and when the rains came we couldn't raise the level.  Because of this the fox found the small access causeway across the trench.  The fear was it might next find the avocets.  A new pair has taken up residence on the Marsh and are seemingly doing a much better job than last time.  A proper nest is in evidence with changeovers in incubation and serious defence against gulls:

With the causeway still present there was a risk of disaster - however luckily there are some guys with diggers handy round the corner who have very kindly cleared it making the interior only accessible by boat again now.  Big thanks to Shane and his team from the EA for this.  Fans of peace and quiet will be pleased to know that all works come to an end tomorrow on the river bank for good, but as previously reported the results should be a great legacy.

Interestingly the avocets seem to feed on Watton and also Hempholme today - again suggesting a lack of food items in South Marsh.  And ultimately black-headed gulls wouldn't seem to be in any danger as a species - this family is one of many still present on South Marsh East alone:

So on to other lighter news:

Well done to John Wilkinson on Monday for finally rounding us up some black terns albeit briefly on D Res.  Also to Mandy James for greenshank the same day.  There have also been further dunlin, redshank and curlew and up to three common sandpipers - thanks to Tony McLean for these:

Likewise HVWG:
Paul Mountain had water rail on North Marsh last night which is great proof of presence in breeding season.  Marsh harrier was over South Scrub yesterday with continued cuckoo actvity.  Drake garganey on South Marsh East too with up to 17 little gulls at a time.  Mistle thrush are hopefully going to nest again after the wet weather last month:

Thanks to Tony McLean for this one of sand martin on the colony:
And also HVWG for these:

And Andy Marshall for this of house martins collecting mud on the access road tonight:

Butterfly developments continue - thanks to Dave Ruffles for these common blues:

Green veined white (DR):
Four spotted chaser (DR):
Blue-tailed damselflies (HVWG):

And the mystery 'whale of Watton' - a substantial fish often seen in the shallows during the warm weather - possibly a carp? (DR):
Possibly a bit big for these two:
Hobby hawking from D res distantly on tuesday:
Finally we're running late on spotted flycatcher this year.  If anyone has seen one we'd love to hear - but we fear it could have become extinct on the site in line with the species national declines.