Willow Warbler – first and last dates

Phylloscopus trochilus – TELOR YR HELYG – Breeding summer visitor and passage migrant.

Previous records summarised in Willow Warbler 1994

YearFirstLast
199325 March19 October
199429 March15 October
199524 March19 October
199624 March9 October
199723 March17 October
199821 March7 October
199930 March28 October
200016 March20 October
200127 March21 October
200225 March21 October
200317 March *14 October
200428 March(8 Oct)
200522 March22 October **
20061 April6 November
20076 April(October)
200831 March13 October
200921 March31 October
20103 April3 October
201126 March16 October
20123 April23 October
201329 March22 September
201427 March14 October
201527 March20 October
201628 March26 October
201719 March27 October
201830 March18 October
201924 March13 October

* 2003 – Remarkably, a wintering bird present Monk’s Haven 14 Feb (SED). This is the second winter record for Pembs, following one singing at Stackpole 9 Feb 1991.

** 2005 –  Final record appeared to be Angle Bay 22 Oct but then another found lingering at The Rhos 5 Dec (J&MB). Only the 3rd record of wintering in the county, the others being in 1991 and 2003.

Records extracted from the Pembrokeshire Bird Reports which may contain more detail.

More about the Willow Warbler in Pembrokeshire

Willow Warbler – 2003-07 breeding

Breeding summer visitor and passage migrant. Not recorded from December to February

Comparison with previous atlas:

1984-882003-07
Breeding confirmed16647
Breeding probable253307
Breeding possible815
No of tetrads occupied427 (of 478)369 (of 490)
Percentage of tetrads89.3%75.3%

This leaf warbler is familiar to many by virtue of its liquid, cascading song. A summer visitor to Britain, wintering in southern Africa, it is normally present in Pembrokeshire from April to September. Scrub, woodland edge and recently planted woodland are its prime habitat, where nests are placed on the ground concealed by vegetation. Willow warblers are normally absent as a breeding bird from the offshore islands, except for the partially wooded Caldey and are not usually found breeding in gardens.

The population estimate which accompanied the 1984-88 survey is now considered to be unsound. Census results from Dyfed Wildlife Trust reserves were applied across the whole county without taking habitat into account, and resulted in an inflated value. Had the findings of the 1988-91 National Atlas been available, a national average value could have been applied and would have resulted in a more realistic estimate of 13,500 pairs nesting in the county.

Comparing the results of the two local surveys indicate a retraction in distribution. The BBS suggests a 20% decrease in Wales between 1994 and 2007, which if applied to Pembrokeshire results in a population estimate of approaching 10,000 pairs nesting by 2007. This accords with the subjective opinion, that Willow Warblers were less numerous during 2003-07 survey than they were during the 1984-88 survey.

Evidence is emerging that this marked decrease is probably due to unfavourable conditions prevailing in the Willow Warbler’s tropical African wintering area.

Graham Rees (County bird recorder 1981 to 2007)

Rees G.H., Haycock R.J., Haycock A, Hodges J.E., Sutcliffe S.J., Jenks P, and Dobbins R. 2008, Atlas of Breeding Birds in Pembrokeshire 2003-07. Pembrokeshire Bird Group.

More about the Willow Warbler in Pembrokeshire

Willow Warbler – 1994

Breeding summer visitor and passage migrant. Not recorded from December to February

1984-88
Breeding confirmed166
Breeding probable253
Breeding possible8
No of tetrads occupied427 (of 478)
Percentage of tetrads89.3%

The Willow Warbler was a common summer visitor according to both Mathew (1894) and Lockley et al. (1949), the latter adding that it was also an abundant passage migrant.

It is a widespread breeding species in Pembrokeshire today (see map) being particularly numerous in some scrub areas, including Castlebythe Common and Waun Cleddau. Using census figures from Dyfed Wildlife Trust reserves as a guide, the average density of Willow Warblers is estimated to be about 100 pairs per tetrad and the total population about 43,000 pairs.

The first Willow Warblers usually arrive during the last few days of March or the beginning of April, though occasionally from 15 March and one was at Skomer on 6 March 1966. Large numbers pass through, with many falls of 100 or more at headlands and islands, including 250 at Skomer on 23 April 1987 and an exceptional 1,000 there on 18 April 1985. Passage continues until mid-, sometimes late, June.

Autumn passage extends from mid-July to early October with stragglers to 24 October. One bird was singing at Goodwick on 28 November 1959. Autumn falls are generally smaller than those in spring, with 40 to 50 birds typically occurring at any locality. Larger counts, up to 150, have been noted, and an exceptional 3,000 birds were at Skokholm in August 1948.

Grey-brown and silvery coloured Willow Warblers have been noted at Skokholm in April and May, and the north European and Siberian subspecies acredula was identified in the hand on 7 and 12 May 1960.

One was seen and heard singing at Stackpole on 9 February 1991.

Donovan J.W. & Rees G.H, 1994, Birds of Pembrokeshire

More about the Willow Warbler in Pembrokeshire

Willow Warbler – 1949

Phylloscopus trochilus trochilus

Common summer visitor, and abundant passage migrant, arrives last week in March.

He also mentions, under the section of the book on Land-Birds:

The first Willow-Warblers are trapped at Skokholm during the last week of March.  This is one of the largest small bird migrations in Pembrokeshire, and for the whole month between mid-April and mid-May there are days when the county swarms with these charming singers.

R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society

More about the Willow Warbler in Pembrokeshire

Northern Willow Warbler – 1949

Phylloscopus trochilus acredula

Recorded at Skokholm 25 and 27 May 1936, and 2 and 12 May 1937.

R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society

More about the Willow Warbler in Pembrokeshire

Willow Warbler – first and last dates

Phylloscopus trochilus – TELOR YR HELYG – Breeding summer visitor and passage migrant. Previous records summarised in Willow Warbler 1994 Year First Last 1993 25 March 19 October 1994 29 March 15 October 1995 24 March 19 October 1996 24 March 9 October 1997 23 March 17 October 1998 21 March 7 October 1999 30 […]

Willow Warbler – 2003-07 breeding

Breeding summer visitor and passage migrant. Not recorded from December to February Comparison with previous atlas: 1984-88 2003-07 Breeding confirmed 166 47 Breeding probable 253 307 Breeding possible 8 15 No of tetrads occupied 427 (of 478) 369 (of 490) Percentage of tetrads 89.3% 75.3% This leaf warbler is familiar to many by virtue of […]

Willow Warbler – 1994

Breeding summer visitor and passage migrant. Not recorded from December to February 1984-88 Breeding confirmed 166 Breeding probable 253 Breeding possible 8 No of tetrads occupied 427 (of 478) Percentage of tetrads 89.3% The Willow Warbler was a common summer visitor according to both Mathew (1894) and Lockley et al. (1949), the latter adding that it was […]

Willow Warbler – 1949

Phylloscopus trochilus trochilus Common summer visitor, and abundant passage migrant, arrives last week in March. He also mentions, under the section of the book on Land-Birds: The first Willow-Warblers are trapped at Skokholm during the last week of March.  This is one of the largest small bird migrations in Pembrokeshire, and for the whole month […]

Northern Willow Warbler – 1949

Phylloscopus trochilus acredula Recorded at Skokholm 25 and 27 May 1936, and 2 and 12 May 1937. R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society More about the Willow Warbler in Pembrokeshire

Willow Warbler – 1894

Phylloscopus trochilus A not very numerous summer visitor. A nest found at Stone Hall, near a pond much frequented by Herons, was entirely lined with the small grey feathers of those birds. Mathew M.A. 1894, Birds of Pembrokeshire and its Islands More about the Willow Warbler in Pembrokeshire

Willow Warbler

Breeding summer visitor and passage migrant. Not recorded from December to February