BISHOP'S STORTFORD AND DISTRICT NATURAL HISTORY SOCIETY
HATFIELD FOREST BREEDING BIRD SURVEY 2014
2nd, 13th, 25th April.
5th, 18th May.
1st, 24th June.
The results are presented in a table in pdf format. Maps have not been produced for those species where the location of nests is uncertain since this would result in false or spurious data, particularly where the species in question probably bred outside the lake survey area.
As in the previous year, predation and/or disturbance were major factors this year in determining the numbers of surviving young. A fisherman who spends some time in the Forest told me that he had seen boaters ignoring the row of buoys and rowing right up to the marsh area. If this type of behaviour becomes commonplace it seems inevitable that breeding attempts will be disturbed. On some visits, absolutely nothing was observed on the Decoy Lake, presumably on account of earlier disturbance by dog-walkers, whose numbers have increased dramatically in recent years.
Great Crested Grebes have had a better year than in 2013 and two broods were recorded, one of at least one juvenile and one of three juveniles.
A pair of Mute Swans again made an attempt to breed at the far end of the Decoy Lake but this nest was abandoned at an early stage and on subsequent occasions only one of the birds was observed, on the main lake on each occasion.
Canada Geese were observed nesting in two places, one of which produced seven young. Greylag Geese numbers peaked at 25 birds on 1st June, but no definite breeding was confirmed in the Lake area. At least two Mallard nests were successful, with broods of 2 and 7 surviving young.
Both Coots and Moorhens were observed on nests and juveniles of both species were observed.
Although the growing vegetation on the tern raft made observation difficult, the Common Terns appear to have been successful this year, with one fully fledged juvenile seen with parents on 11th July.
Other breeding successes included the Swallow, where 5 juveniles were successfully reared in the Fishermen's Shelter and the Reed Bunting, where adults were observed carrying food. Reed Warblers are assumed to have bred in the reedbed at the marsh end of the lake, since territorial behaviour was observed on various occasions. Although juvenile Robins and Dunnocks were both observed, it cannot be stated with certainty where their nests were located since the birds were fledged and hence mobile. However, territorial behaviour of both species was observed within the survey area. Jackdaws presented a bit of a problem this year since their prime nesting tree lost a significant part of its superstructure during the winter gales, including many of the hollow branches. As a result there appears to have been some intense competition for nesting sites within the other unaffected trees, possibly to the detriment of Stock Doves where fewer were observed than in previous years.
16th July 2014.