Little Grebe – 2016 WeBS

Tachybaptus ruficollis – GWYACH FACH – Breeding resident and winter visitor

Little Grebe counts for the Wetland Bird Survey (WeBS) in Pembrokeshire.  Note that data prior to 1995-96 are incomplete.

The distribution and the breeding population of little grebe in Pembrokeshire have increased dramatically in the past twenty years, but this has not been reflected in the wintering population on the estuary system.

The decline on the estuary is largely accounted for by the decline in the wintering population on Westfield Pill, which was considered a stronghold for the species after being dammed in the late 1980s.  It is possible that, as the Pill has matured and stabilised as a slightly saline lagoon, conditions may not be quite as suitable for little grebe. 

From the mid-1990s, numbers wintering on WeBS sites in the county appeared reasonably stable at around 100 birds, but the total on the estuary has declined.  This was almost certainly linked to the milder winters since then.  If smaller ponds are not freezing over, then birds are not forced to move to the estuary to feed. In 2013-14 there has been a further decline to around 65 birds.  It is likely that there are more birds in the county, particularly on the more recently-created ponds which are not counted for WeBS.

During the cold winter of 2010-11, numbers in the county reached the highest level recorded on WeBS sites.  This could be the result of local movements away from small water bodies that are not regularly monitored, or from other parts of the country.  Across the UK, numbers declined that year, suggesting that birds either moved further south, and/or succumbed to the bad weather.

The slow but steady increase in Little Grebes across Britain, that appeared to begin in the early 1990s soon after the species was first routinely monitored, has continued in recent years; a period during which numbers have risen concurrently in The Netherlands.  This increase has led to large changes in the levels of international and national importance for this species, and the Cleddau Estuary now falls well below the national threshold.

Why the wintering little grebe population in Pembrokeshire as a whole has not increased in line with that in the rest of the UK is unknown.

Annie Haycock (BBS & WeBS local organiser)

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Little Grebe – 2011

Tachybaptus ruficollis – GWYACH FACH – Breeding resident and winter visitor

Breeding

The Little Grebe breeds throughout the temperate and tropical Old World and is resident, dispersive and migratory.

In Pembrokeshire it inhabits still fresh waters in the breeding season so is absent from the fast flowing rivers and streams. It requires waters to be vegetated around the fringes and beneath the surface. It is secretive and inconspicuous around the breeding area and can easily be overlooked, its far carrying, distinctive, whinnying call often being the first indication of its presence.

The breeding status of this species in the county in the past is difficult to evaluate. To Mathew (1894) it was a breeding species but by 1949 Lockley et al stated “apparently does not breed”.

Saunders (1976) commented “Strangely it does not remain to breed, for at least to human eyes, there are several suitable waters.”

However, Bertram Lloyd’s diaries contain records of breeding at Llambed in 1936 and suspected breeding at Slebech in 1937 and Sharrock (1976) indicated possible breeding between 1968 and 1972 in the south west of the county.

Donovan and Rees (1994) quoted breeding at Thornton Reservoir (now defunct) in 1965, at Pembroke Mill Pond in 1975 and at Trefloyne in 1981, with suspected breeding at Bosherston during the 1970’s and 1980’s.

The lack of breeding during the review periods of Lockley et al and Saunders might well have been the result of severe winters in 1939-40, 1947-48 and 1962-63 eliminating a small population which was previously present.

Comparison of the results of the two breeding bird surveys of 1984-88 and 2003-07 indicates an almost fourfold increase in the number of occupied tetrads during the elapsed period. Most birds were on well vegetated farm ponds used for irrigation. Many of the ponds used in 2003–07 had only recently been constructed in the 1980s and only subsequently became vegetated and thus suitable for Little Grebes.

Although most small waters were used by just one breeding pair, some tetrads encompassed more than one such body of water and on some larger waters there was more than one pair, for instance there were four pairs at Marloes Mere. Allowing for these variables, the county total was estimated to be about 70 pairs by 2007, compared to 12 pairs in 1988.

Migration

The Migration Atlas (2002) suggests that most Little Grebes disperse from their breeding area to winter elsewhere. It also states that there are still many unknowns about their migration, citing very few examples of immigration based on ring recoveries. BWP considered autumn and spring records on or near the British east coasts, especially at lighthouses, indicated immigration from the Continent.

There are no records of Little Grebes visibly migrating in Pembrokeshire, possibly meaning they pass at night but there have been none noted at local lighthouses. Diurnal records of birds on the sea at Strumble Head and Skomer and visiting ponds on Skokholm, Ramsey and most frequently Skomer, indicate dispersal at least and possibly longer distance migration as well.

Winter

Outside of the breeding season Little Grebes have been recorded on all of the estuaries and main freshwaters, as well as on many small ponds.

The Little Grebe was originally classified as a winter visitor by Lockley et al (1949) and Saunders (1976) when there were no known breeding birds in the county and they noted them on small ponds, lakes, reservoirs and estuarine arms. Only Saunders put any numbers to these occurrences, citing up to 20 on the Gann lagoon and 32 in Hook Reach.

Largest concentrations recorded between 1983 and 2005 were: Cleddau Estuary 69, Nevern Estuary 9, Teifi Estuary 8, Freshwaters 97.

Donovan and Rees (1994) estimated the average county winter population to be about 150 birds. Within the cover achieved by the Wetland Birds Survey team over 100 are on record for most recent winters, the maximum being 162 in the winter of 1996/97. However the survey could not cover all the small waters on which Little Grebes have been seen but seldom reported, so the 150 estimate on average is probably realistic or possibly a slight under estimate.

Haycock (2008) noted a decline in Cleddau Estuary numbers from about the 1990’s and suggested this could be due to Westfield Pill becoming less suitable for this species. She also pointed out that the mid- winter population for the whole county was reasonably steady overall.

Normally they have started to appear on the estuaries in August and September and reached peak numbers by November to January, thereafter numbers diminished with most having departed by April.

Sea Empress Oil Spill 1996

When the oil – spill caused by the grounding of the Sea Empress occurred, 15th – 21st February 1996, the Milford Haven waterway was badly contaminated, most heavily as far upstream as the Cleddau Bridge. Little Grebes quickly left this area, moving to safer places, notably to Westfield Pill where their presence rose from 39 to 52 birds. None were recorded dead or visibly oiled, so their rapid evasive action was evidently effective.

Graham Rees. Pembrokeshire County Bird Recorder 1981-2007

DONOVAN. J and REES. G. 1994. Birds of Pembrokeshire, Dyfed Wildlife Trust.

HAYCOCK. A. 2008. A review of the status of wetland birds in the Milford Haven Waterway and Daugleddau Estuary, A report to the Milford Haven Waterway Environmental Surveillance Group. Unpublished.

LLOYD. B. 1929-1939 Diaries, National Museum of Wales.

LOCKLEY. R. M, INGRAM. C. S. and SALMON. H. M.1949. The birds of Pembrokeshire, West Wales Field Society.

MATHEW. M. 1894. The birds of Pembrokeshire and its islands, R. H. Porter.

SAUNDERS. D. R. 1976. A brief guide to the birds of Pembrokeshire, Five Arches Press.

SHARROCK. J.T. R. 1976. The atlas of breeding birds in Britain and Ireland, Berkhamsted, T. & A. D. Poyser.

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Little Grebe – 2003-07 breeding

Tachybaptus ruficollis – GWYACH FACH – Breeding resident and winter visitor

Comparison with previous atlas:

1984-882003-07
Breeding confirmed631
Breeding probable39
Breeding possible511
No of tetrads occupied14 (of 478)51 (of 490)
Percentage of tetrads2.9%10.4%

The little grebe inhabits still fresh waters in the breeding season so is absent from the county’s fast flowing streams and rivers. It is secretive and inconspicuous around the breeding area and can easily be overlooked, however its distinctive far–carrying, whinnying call often betrays its presence. The nest is a floating platform of vegetation which is anchored to reeds and overhanging branches.

Comparison of the results of the two surveys indicates an almost four-fold increase in the number of occupied tetrads during the elapsed period. Most pairs were recorded on well-vegetated farm ponds used for irrigation, where there is an abundance of food in the form of small fish and invertebrates. Many of the ponds used in 2003-07 had only recently been constructed in the 1980’s but have subsequently matured, becoming vegetated and therefore suitable for Little Grebes.

Although most small waters are used by just one breeding pair, some tetrads encompass more than one such body of water and at Marloes Mere for instance, there have been four breeding pairs. Allowing for these variables, the county total was estimated to be about 70 pairs by 2007, compared to 12 pairs in 1988.

Graham Rees. Pembrokeshire County Bird Recorder 1981-2007

Rees, et al. 2008, Atlas of Breeding Birds in Pembrokeshire 2003-07. Pembrokeshire Bird Group.

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Little Grebe – 1994

Tachybaptus ruficollis – GWYACH FACH – Breeding resident and winter visitor

Map produced by the West Wales Biodiversity Information Centre
1984-88
Breeding confirmed6
Breeding probable3
Breeding possible5
No of tetrads occupied14 (of 478)
Percentage of tetrads2.9%

Mathew (1894) stated that the Little Grebe was a breeding species in Pembrokeshire but was more frequent in the winter months. Lockley et al. (1949) considered that it did not breed but was numerous in the winter. Saunders (1976) also regarded it as a non-breeder.

Lloyd proved breeding at Llambed in 1936 and suspected it at Slebech in 1937. Breeding was proved at Thornton in 1965, at Pembroke Mill Pond in 1975, at Trefloyne in 1981 and was suspected at Bosherston Pools during the 1970s and 1980s. The Dyfed Wildlife Trust Breeding Birds Survey of 1984-1988 discovered that about a dozen pairs of Little Grebes bred. The localities included Llambed where the grebes were particularly secretive and difficult to see, just as Lloyd noted in 1936, and it is tempting to think that they may have bred there throughout the intervening years.

The Little Grebe is more widespread and numerous in the winter months, when it can be found on estuaries and fresh waters, often occurring on quite small farm irrigation reservoirs. Up to five birds is normal at most localities but there are sometimes larger gatherings at favoured spots: up to seven in the Nevem Estuary, ten at Bosherston Pools, 13 at Carew/Cresswell, 32 at the Gann and in Hook Reach and 40 at Pembroke Mill Pond, the total winter population being about 150 birds. The numbers and pattern of occurrence noted by Lloyd (1925-1937) are consistent with that seen today, suggesting that Lockley et al. were interpreting a similar situation when they described this bird as “numerous”.

Little Grebes have not been seen migrating during the day and it is presumed that the occasional occurrence of birds at Skokholm and Skomer and on the open sea off Strumble Head refer to grounded night migrants. 

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

LLOYD, B. 1925—1939. Diaries. National Library of Wales

SAUNDERS, D.R. 1976. A brief guide to the birds of Pembrokeshire. Five Arches Press

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Little Grebe – 1980s winter

Tachybaptus ruficollis – GWYACH FACH – Breeding resident and winter visitor

The BTO winter atlas showed that Little Grebes were present in about 56% of Pembrokeshire 10km squares during the winters of 1981-82, 1982-82 and 1983-84, being found on both fresh and estuarine waters.

The darker the colour, the higher the relative total count for each 10km square.  The darkest blue represents over 9 birds, 25 being the Pembrokeshire maximum.

Graham Rees. Pembrokeshire County Bird Recorder 1981-2007

Data collected by volunteers for the BTO. Lack, P. 1986 Atlas of wintering birds in Britain and Ireland. T & A.D. Poyser.

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Little Grebe – 1936

Tachybaptus ruficollis – GWYACH FACH – Breeding resident and winter visitor

Extracts from the diaries of Bertram Lloyd, 1936.

14th March: 1 Llanbed Pools, Mathry

26 June:  Llanbed Pools, “We saw 2 well grown young persistently uttering the peep—peep hunger call, though for an hour or more left by their parents, Later we saw one parent feeding a young bird. The parents were particularly furtive here, apparently avoiding the open parts of the not very large pond by Lambed farm. This is the first sight have ever had of nesting Little Grebes in the county and possibly this was the first nesting pair—though I have never been at this pond before in the breeding season.”

5 July “now well grown.”

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Little Grebe – 1894

Tachybaptes fluviatilis – Resident.

The Little Grebe, or Dabchick, as it is most commonly called, is the smallest of the Grebe family, and is the only one that nests in Pembrokeshire, and commonly throughout the British Isles. It is more frequently seen in the winter months, because then there is less cover of aquatic vegetation in which to conceal itself.

We have seen it on the Cleddy, beneath Stone Hall, and in hard weather noticing two or three on the water in company have occasionally stalked them, as from a distance we have taken them for Teal; but as we approached their diving at once revealed to us what they were. The Little Grebe frequents pools, lakes and the still waters of rivers and streams wherever there is sufficient cover to hide, and here it can easily escape detection, as it will dive, and when it comes up again to breathe will do so among the leaves and rushes by the bank, where it only thrusts its head above the surface and cannot be seen. We have amused ourselves by watching them diving in this way in our fish ponds, and although quick sighted and familiar with their habits, they very frequently managed to come up somewhere where we could not see them.

Like all the other Grebes this small species visits the tide-way in the winter, where we have seen and shot it in salt water.

Mathew M.A. 1894, Birds of Pembrokeshire and its Islands

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