Tuesday, 14 May 2013

Spring at Upton Broad and Marshes

Nigel Robson, Volunteer Bird Recorder for NWT

Birdlife at Upton from February, through March and well into April reflected little change due to persisting cold easterly winds. Mark Crossfield of the reserve staff now regularly watches birds at Upton and his records are combined with mine for this and future posts.

The wintering pintail was last noted at the river lagoons on 14 March, at which time oystercatchers arrived in their breeding ground, six weeks later than the shelducks. Gadwalls were assembling on the grazing marshes, peaking at 48 on the 26th, and at the same time shovelers were gathering on Great Broad, with a maximum of 20 on the 24th. A few dunlin passed through, including a group of seven on the 26th. Teal remained the most numerous duck at the marshes with some 200 staying into April, by which time a few Wigeon had joined them.

After a paucity of starlings on the grazing marshes during the winter months, hundreds appeared on 28 March. The wintering peregrine was there to take advantage, once causing the flock to rise in a spiralling cloud before diving in from above - and moments later making off low with a bird in its talons. Other raptors regularly seen were a resident pair of marsh harriers, a recently arrived pair of buzzards in the woodland, sparrowhawks and kestrels. Barn Owls appeared not to be reduced in number despite reports throughout the country of a high mortality during the cold weather, though they tended to keep hunting throughout the day which may be an indication of reduced availability of prey.

The anticipation of spring was finally realized in mid-April with the sounds of chiffchaffs, soon followed by blackcaps, whitethroats, sedge, willow and grasshopper warblers, and finally reed warblers. The cuckoo was back before the end of the month, as yet remaining a familiar sound across the marshes every spring.

Pairs of waders occupied their territories on the marshes. Conditions were not as optimal as had been hoped after the ample winter rainfall, high winds causing water in some shallow scrapes not linked in with the dyke systems to evaporate quickly. Nonetheless the lowest grazing marshes attracted some 8-10 pairs of lapwing, three of redshank and one each of oystercatcher and little ringed plover.
Whimbrel, photo by Lawrie Webb
Some of the regular passage migrant species were well represented towards the end of April, and others less so. There is always a strong passage of whimbrel at Upton, and this spring a steady build up of numbers reached 73 on the 28th. Unlike last year, no bar-tailed godwits were seen amongst them. A pair of pintail was present at the river lagoons on the 21st. A pronounced fall of migrants on 27th included many yellow wagtails (including blue-headed forms), two white wagtails, seven wheatears, a whinchat and a stonechat on the marshes, and four ring ouzels and a lesser whitethroat in the tall hedgerows.  Up to 34 golden plover were well concealed in an adjoining wheat crop for several days during this time. Waders stopping on passage on the exposed mud of the tidal lagoons were fewer in number and variety this April than last (the first year of the lagoons existence) with a few snipe and the odd common sandpiper and greenshank. Visually the conditions seemed favourable enough – possibly invertebrate richness has reduced after the first spring following the laying down of the dredgings, or there may simply have been fewer birds about during so late a spring.  

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