Thursday, 26 February 2009


In 1990, after an absence of over 60 years as a breeding bird in Hertfordshire, a pair of BLACK-NECKED GREBES bred successfully in South Hertfordshire. The birds first appeared at the beginning of June and began displaying almost immediately. They were observed daily and on the 10 June, were observed carrying weed into a Typha bed in the SE corner of the reservoir. By the end of June, only one bird could be found, and after careful scanning, the other bird was found sitting on a nest, well hidden at the edge of the reedbed.
On the evening of 22 July, both adults were out on the water and closer inspection revealed three young on the back of one of the adults. The feeding of the young was done by both parents with the distribution of food down to the determination of the individual. By 7 August, one juvenile was already independent and by 18, one adult had departed. Two juveniles remained until 5 September.
This was the first confirmed breeding of Black-necked Grebe in Hertfordshire since 1928 when a pair were believed to have bred on Wilstone Reservoir.
In 1991, a single calling bird in breeding plumage returned on 18 May with a juvenile there from 12-19 July, whilst a displaying pair returned from 30 April to 4 May 1992, with another pair on 28 May 1992. The following year just singles turned up on 26 and 29 April and 5 May 1993, with the same again on 2-5 July and 17 September 1994.
Following a blank year in 1995, an adult and a juvenile was present from 31 July to 5 August 1996, with the adult remaining until 8 August and a juvenile again on 24 August, with a pair again present from 23 March to 5 April 1997.
1998 spawned another bout of breeding success and following a pair present on 24 May, successful nesting was finally confirmed on 27 June. At least one adult remained with four young until 26 July with the young birds remaining until 7 September.
In 1999, two pairs summered with breeding attempted but unsuccessful. A single adult arrived on 1 April, followed by 3 birds from 22 April to the end of May. Two formed a pair and were often seen displaying, increasing to two pairs throughout June with nest-building observed. Up to 3 birds stayed throughout July with just one remaining until 11 September.
With the new Millenium, successful breeding took place including the remarkable fostering of a chick by a pair of Great Crested Grebes. The first bird of the year arrived on 19 March, with 7 the next day. Up to 6 were then present from April-June peaking at 7 adults again in July. It appeared that nesting attempts by 2 or 3 pairs failed following a period of heavy rain, which may have washed out nests. However, in early July 2000, a newly hatched brood of Great Crested Grebes was seen to include a single Black-necked Grebe chick Although it received some aggression it was fed fish rather than the more invertebrate diet, and brooded on the adult's back. The chick grew quickly and was independent by the end of the month, although it continued to associate with Gret crested rather than Black-necked Grebes. It remained until at least the third week of August when finally, a late brood of two Black-necked Grebes appeared, presumably the results of a second brood. One bird probably fledged, with the last adult seen on 27 August.
With fortunes mirroring the species' national success in 2001, where the population increased to at least 70 pairs, the small but increasing Hertfordshire population eventually reared three broods. The first two birds appeared on 22 March, increasing to 6 during April, 8 during May and a peak of 11 on 2 June. Early breeding attempts probably failed as the three broods totalling only four young appeared late in the season again. The last bird was noted on 17 September.
In 2002, the breeding population increased slightly again to four pairs nesting, although only one chick was ever seen most probably due to the wet weather all spring. The first two returned on 2 March and increased to a peak of 10 birds on 10 April. The last was seen on 25 September.
2003 was a record year with five pairs having unusually high success with five broods each of two young being reared. The first two birds arrived on 6 April, a month later than in 2002, and increased to a peak of 11 birds as the month progressed. However 2003 was eclipsed by 2004, when an incredible 9 pairs bred with eight broods hatching and at least 12 young fledging. The first two birds arrived on 17 March and increased to a peak of 18 in April. Following such a good year, four birds remained to overwinter.
In 2005, five broods were recorded, rearing 13 young, the largest number to date. The first bird arrived on 27 February, with up to 14 present March-August with a peak of 21 on 15 April. Numbers declined to a maximum of 7 in September and 1-2 until 13 November.
Despite a record number of 25 birds present in April 2006 and up to 16 during May to July, none was recorded as breeding. The last bird lingered until 29 October.
Breeding took place in 2007 and 2008 (details not available) with a single first-winter remaining into January-February 2009.

No comments:

Post a Comment