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 (County bird recorder 1981 to 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.

More about the Little Grebe in Pembrokeshire