Carrion Crow - 1949 status

Corvus corone corone

Common resident, nesting on cliffs, trees, in bushes and on derelict buildings.

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

Carrion Crow - 2003-07

The all black appearance of the Carrion Crow means it is easily confused with the Rook. The curved bill and lack of a bare throat differentiates it from the Rook, as does the call and keeping its nest in a discrete territory rather than in a colony. The bulky stick nest, placed high in a tree, is usually conspicuous before leaves appear. In Pembrokeshire they also nest on cliff ledges.

The estimate that accompanied the 1984-88 survey was based on the distances between nests in a small number of random localities. With no other information available at the time, this was used to calculate a county total breeding population of 18,000–21,000 pairs. With the benefit of hindsight this is now considered to be an inflated total. The 1988-91 National Atlas showed Pembrokeshire contained Carrion Crows at maximum abundance and if their UK average density is adjusted to allow for this, suggests a county population of about 10,000 pairs, which seems realistic. The 2003-07 survey found no marked difference in distribution from the 1984-88 survey, so there has probably been no change in the size of the population.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 354

Orange = breeding probable = 51

Yellow = breeding possible = 48

Total tetrads in which registered = 453 (92.4%)

Carrion Crow - 1994

Breeding resident

Mathew (1894) and Lockley et al. (1949) agreed that the Carrion Crow was a common resident.

They were formerly persecuted throughout Pembrokeshire: 134 were killed on the Cawdor Estate at Stackpole in 1821 (Carmarthen County Records Office, Box 1-234) and Lloyd counted 150 on a gibbet at Slebech in 1930. Although still sometimes shot by game preservers and shepherds, they are now largely unmolested.

They breed over a wide area, mostly in trees but also on cliff ledges, and have occupied most of the offshore islands (see map). They used to breed on Ramsey, but were eradicated, at least temporarily, by trapping during the 1980s, and have declined at Skomer, perhaps due to increased competition for food and nest sites from Magpies. The distances between nests were noted in a number of areas of the county during 1986 and 1987 and used to estimate an average density of 40-45 pairs per tetrad, suggesting a county population of 18,000-21,000 pairs.

Groups of non-breeding birds, sometimes up to 100 strong, gather on the estuaries during the summer to feed on shellfish, notably at Fowborough and the Gann. This habitat is also utilised by family parties after the breeding season and throughout the winter, when up to 200 may gather.

Lockley (1957) stated that roosting flocks of up to 100 were common in Pembrokeshire but most modem records refer to 60 or less, though 208 were counted gathering at Dowrog in November 1988.

They are perhaps partial migrants, judging by records of birds overflying remote offshore areas such as the Smalls or flying in or off the sea at headlands, and a nestling ringed at Bardsey was later found in north Pembrokeshire.

Hooded Crows, which occur most years on the islands of Ramsey, Skokholm and Skomer, or at the coast in localities such as Fishguard Harbour, St David's, Solva and Martin's Haven, undoubtedly come from elsewhere, most likely from Ireland. They have turned up in every month and individuals have sometimes made prolonged stays. One which wintered at Fishguard Harbour in 1986/87 was seen displaying in the spring and may have attempted to breed.

Fieldwork 1984-88 (based on 478 tetrads) 

Red = breeding confirmed = 390

Orange = breeding probable = 22

Yellow = breeding possible = 47

Total tetrads in which registered = 459 (96%)

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

Carrion Crow - 1970s breeding

Red = breeding confirmed

Orange = breeding probable

Yellow = breeding possible

Carrion Crow - 1980s winter atlas

The BTO winter atlas showed that Carrion Crows were present in all 10km squares during the winters of 1981-82, 1982-82 and 1983-84.

The darker the colour, the higher the relative total count for each 10km square.  The darkest blue represents over 130 birds.

However, it should be noted that the figures show a high correlation with the number of recording cards returned (therefore related to recording effort) for each 10km square. 

BTO atlas

Carrion Crow - 2010

Corvus corone

Breeding resident.

The Carrion Crow was assessed as common and widespread in Pembrokeshire by Mathew (1894), Lockley et al (1949) and Donovan and Rees (1994). They were persecuted by gamekeepers during Mathew’s time, a hint of the scale being the record of 134 killed on the Cawdor estate in 1821. This continued into the Lockley et al era, an example being 150 counted on a gibbet at Slebech in 1930. Such carnage diminished during the two World Wars when many gamekeepers were recruited to the armed services. Control measures are still attempted but on a small and localised scale, so they are now unmolested over much of their county range.   

Nesting in trees, on old buildings and cliff ledges, the Carrion Crow has been found breeding all over the county, including the major offshore islands. Its breeding distribution was plotted in 1984 – 88 by a survey using tetrads as a grid and this was repeated in 2003 – 07.

Breeding surveys	1984 – 88	2003 – 07
Total tetrads where found	459	453
Confirmed breeding	390	354
Probable breeding	22	51
Possible breeding	47	48

An estimate of the breeding population was attempted following the survey of 1984 – 88, which was based on the distances between nests in a small number of random localities. With no other information available at the time, this was used to calculate a county total breeding population of 18,000 – 21,000 pairs. With the benefit of hindsight this is now considered to be an inflated total. The BTO’s New Atlas of 1988 – 91 showed Pembrokeshire contained Carrion Crows at maximum abundance and if their UK average density is used as an adjustment, a county population of about 10,000 pairs results, which seems more realistic. The 2003 – 07 survey found no marked difference in distribution from the 1984 – 88 survey, so there was probably no change in the size of the breeding population.

Being a successful breeder the Carrion Crow produces a surplus component to its population, comprised of immature birds that are too young to breed or adults which cannot find a vacant breeding territory. In places these form flocks which have been most noticeable on parts of the estuaries such as Fowborough and the Gann. This “reservoir” enables territories made vacant by various means, like shooting, to be recolonised.

There are several records of Carrion Crows flying in off or out to sea at headlands and islands, as far out as The Smalls, but the only concrete evidence of migration was of a nestling ringed on Bardsey Island which was recovered in north Pembrokeshire. 

Graham Rees.

(Covers records up to and including 2010)

Carrion Crow - 1894

Species account from M Mathew, 1894, "The Birds of Pembrokeshire and its islands"

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