Green Heron

Butorides virescens (Linnaeus, 1758) (1, 0)

Photo © Iain H Leach

STATUS

Nearctic. Polytypic.

OVERVIEW

Not admitted onto the British List until 1974, the reason being the reluctance to accept natural transatlantic crossings.

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RECORD

1). 1889 Cornwall Penrice, St Austell, immature, shot, 27th October, photo, now at Royal Cornwall Museum, Truro.

(M. A. Mathew, Zoologist 1890: 105-106; J. E. Harting, Zoologist 1890: 181-182; Eds., Ibis 1890: 386-387; Saunders, 1899; J. Clark, Journal of the Royal Institution of Cornwall 17: 131; Clark, 1907; R. Hudson, British Birds 65: 424-427; Penhallurick, 1978: 414, photo p. 404; BOURC (1974), Ibis 116: 578; BOURC (1993) 135: 220).

History M. A. Mathew of Buckland Dinham, Frome (1890) in The Zoologist, 3rd series, Vol. XIV. pp. 105-106, says: 'Towards the end of last year I saw in the shop of Mr. Foot, the birdstuffer, in Bath, a small heron which was new to me, and which he told me had been shot at large by a gamekeeper in Cornwall during the past autumn.

From an inspection of some skins at the South Kensington Museum of Natural History, I have since been able to determine that this is a young example of Ardea virescens, the Common Green Heron of the United States. The bird shown to me was in perfect feather, and had no appearance of being in confinement, and must be looked upon as another addition to the long list of stragglers from North America which have visited this country.' [So many instances are on record of the occurrence in Great Britain and Ireland of the American Bittern, Ardea lentiginosus, that there is à priori improbability of its smaller relative A. virescens having also found its way accidentally to this country. At the same time it should be borne in mind that so many ornamental water-birds are now-a-days imported by dealers that the chance of some of these making their escape and being found at liberty in perfect plumage is being daily increased. Considerable caution should therefore be exercised before regarding any New World species as a genuine immigrant unaided by man's intervention. We have yet to learn whereabouts in Cornwall, and under what circumstances, the specimen above referred to was taken. - Ed.]

J. E. Harting (1890) in The Zoologist, 3rd series, Vol. XIV. pp. 181-182, says: 'In The Zoologist for March last (p. 105) Mr. Murray Mathew reported that he had seen a small heron, which he believed to be Ardea virescens of the United States, in the shop of Mr. Foot, taxidermist, of Bath, who informed him that it had been shot in Cornwall in the autumn of last year.

Within the last few days the owner of the bird in question, Sir Charles Sawle, Bart., has been good enough to bring it for my inspection, and at my suggestion it was exhibited by him at the last meeting of the Linnean Society on April 17th.

His account of it is that on the 27th October last his keeper, William Abbott, was trying for the proverbial "early Woodcock" on some low-lying ground known as Hay Bottom, at Penrice, St. Austell, when the bird was flushed by a spaniel which almost succeeded in catching it. The keeper shot it, and, seeing that it was a bird with which he was quite unacquainted, sensibly kept it to show his master, who forwarded it for preservation to Foot, of Bath, as already stated.

There it got labelled by someone who ought to have known better, "Nanking Night Heron", which it does not in the least resemble. On seeing it I had no hesitation in pronouncing it to be Ardea virescens, as suggested by Mr. Mathew, although not a young bird, as he supposed, but a fairly adult one. Possibly he may have regarded it as immature because it does not present the brighter green colour and long dorsal plumes which characterize the breeding plumage.

In order to be quite certain of the species, in company with Dr. Sclater and Mr. Sharpe, I compared it with a number of skins of A. virescens at the Natural History Museum, when it was apparent that Mr. Murray Mathew's identification was quite correct.

As to how this wanderer from the United States of America found its way to Cornwall, I can only hazard the conjecture that it may have come off from the shore at twilight (Bitterns like Herons are very crepuscular in their habits), and may have perched on the rigging of some vessel which may have shortly weighed anchor and carried it out of sight of the coast. On nearing land again after crossing the Atlantic, it may have taken wing as soon as it perceived the shore, and have gradually moved to the place where it was found and shot.

An obvious objection to this theory is that it could have eaten nothing under the circumstances for eight days. But Bitterns like Herons may have great powers of fasting....I have only to add that, in the opinion of Dr. Sclater, this bird should be referred to the genus Butorides, the species of which possess characters that naturally place them between the true Herons (Ardea) and the Little Bitterns (Ardetta), and in this opinion Mr. Sharpe concurs.'

In an Editorial (1890) in The Ibis, Vol. XXXII. pp. 386-387, he says: 'At the Meeting of the Linnean Society on the 17th April last, Sir Charles Sawle exhibited a specimen of the North American Little Heron, Butorides virescens, which had been shot by his keeper, W. Abbott, on the 27th of October, 1889, on his estate, Penrice, St. Austell, Cornwall.

The specimen was brought to Sir Charles in the flesh, and forwarded to Mr. Foote, birdstuffer, Bath, for preservation....this is the first recorded example killed in Great Britain.'

Saunders (1899: 386, 2nd ed.) in a footnote, says: 'A specimen of the American Butorides virescens, said to have been shot in Cornwall in October 1889, was exhibited at the Linnean Society in April 1890, by Sir C. Sawle (cf. Zool., 1890, p. 105 and p. 181).'

J. Clark (1907) in the Journal of the Royal Institution of Cornwall, Vol. XVII. p. 131, under 'American Birds in Cornwall', says: 'Was shot by the gamekeeper of Sir Charles Sawle, Bart., at Penrice, St. Austell, on October 27th, 1889, and exhibited for the owner by J. E. Harting, at a meeting of the Linnean Society in April, 1890 (Zool., 1890, pp. 105 & 181).

The specimen is now in the Museum of the Journal of the Royal Institution of Cornwall.'

J. Clark (1907 (1): 339) in the Victoria County History of Cornwall, says: 'Little Green Heron - The only British representative of this wanderer from tropical and temperate America was shot at Penrice, St Austell, on 27 October, 1889, and exhibited at the Linnean Society in April, 1890, by Sir Charles Sawle. The specimen is now in the museum of the Journal of the Royal Institution of Cornwall [Truro].'

Robert Hudson (1972) in British Birds, Vol. LXV. pp. 424-426, says: 'Until the early 1950s, leading British and Irish ornithologists were notoriously reluctant to admit the possibility of natural transatlantic crossings by land birds. This was the attitude of Howard Saunders, one of the most influential ornithologists of the Victorian era, and the same line was followed by, among others, R. J. Ussher in Ireland and Dr. E. Hartert and H. F. Witherby in Britain.

Records of Nearctic waterfowl, waders and gulls were acceptable, as were those of American Bitterns Botaurus lentiginosus and Yellow-billed Cuckoos Coccyzus americanus in view of the numbers that occurred; but most records of other North American species were dismissed as due to assisted passage or importation.

More recently, especially since meteorological analysis by Williamson (1954) and a survey of Nearctic land bird records in Europe by Alexander and Fitter (1955), transatlantic crossings have been regarded as natural phenomena.

The Records Committee of the British Ornithologists' Union has given retrospective acceptance to old records of Sandhill Crane Grus canadensis (Co. Cork, September 1905), Slate-coloured Junco Junco hyemalis (Co. Clare, May 1905) and Black-and-white Warbler Mniotilta varia (Shetland, October 1936). Doubtless some other early occurrences of Nearctic species merit reconsideration where documentation is possible; the present note concerns one more which has recently been reconsidered. The Green Heron Butorides virescens is a common migratory species in eastern North America, but the record under discussion here is the only occurrence known in Europe.

This individual, at Penrice, near St Austell, Cornwall, on 27th October 1889, was almost caught by a spaniel before being shot by the gamekeeper to Sir Charles Sawle, Bt. It was sent to a Bristol taxidermist, in whose shop it was seen and identified by Mathew (1890), the contemporary chronicler of Devon bird-life; subsequently it was forwarded to the British Museum (Natural History) where the identity was confirmed by Harting (1890), Dr. P. L. Sclater and R. Bowdler Sharpe.

No reason was ever given for not then admitting the species to the British and Irish list; if the authorities of the period suspected it might have been an escape from captivity, their fears were not stated at the time. Saunders (1899) 2nd edit., Hartert et al. (1912) and the B.O.U. (1915) all hid behind the phrase 'said to have been shot', but there is no reasonable doubt that the specimen was shot when and where reported, this being tacitly admitted by Witherby et al. (1940-52) with the words "...was shot in Cornwall...".

The specimen is now preserved in the County Museum, Truro, Cornwall, where it has recently been re-examined by R. D. Penhallurick, to whom I am grateful for providing photographs and a plumage description.

The bird is in adult-type plumage, characterised by having the crown black glossed with green, dark green-glossed upperparts apart from some brown edgings among the wing-coverts, rich chestnut cheeks and sides and back of neck, whitish foreneck with vertical lines, and unstreaked grey-brown underparts. In this specimen, however, the elongated, lanceolate scapulars are considerably shorter than those of the nuptial plumage, as previously reported by Harting; while the erectile feathers of the crest, too, are shorter than in breeding dress. Presumably these feathers were still developing when the bird was killed.

This adult-type plumage is first acquired in the late summer or autumn of the second calendar year, but it is not possible to age the Cornish specimen further. I have long considered this record a genuine one. The occurrence in late October in a western county is suggestive of a wild vagrant. More important, and a factor not appreciated by previous authors, was the simultaneous occurrence of two American Bitterns in Ireland, one shot in Co. Kildare on 31st October and the other in Co. Londonderry on some day at the end of that month (Zoologist, 1890: 24, 26); these records demonstrate that meteorological conditions over the North Atlantic had been compatible with west-east crossings.

Moreover, the fact that the Green Heron was almost caught by a spaniel suggests that it may have been exhausted. The Zoologist accounts of the heron made slight reference to the escape possibility, but, despite the wide circulation which that Journal had at the time, nobody came forward to report a loss or even a possible source; indeed, there is no evidence that any were being held in British collections. The Cornish specimen was in unworn plumage and bore no marks of captivity (Mathew).

The Green Heron occupies a wide range of damp habitats, both freshwater and marine: ponds, rivers, wooded streams, marshes, mangrove swamps and shores. The breeding range extends over North and Central America south to Panama, and throughout the West Indies; seven subspecies are recognised. The nominate race occupies eastern North America from southern New Brunswick, southern Quebec, southern Ontario and central Minnesota south to the Gulf States and Mexico; except for some birds in Florida, southern Texas and Mexico, it is a migratory population, wintering mainly south of the breeding range as far as Colombia and Venezuela. The main passages through North America occur in March-April and September-October; the species has straggled on several occasions to Bermuda, Manitoba, Nova Scotia and Newfoundland, and once to west Greenland. (Data in this paragraph are taken from Palmer 1962).

The Green Heron is sometimes considered to be conspecific with the Green-backed or Striated Heron Butorides striatus, which has a wide range in South America, in islands of the Pacific and Indian Oceans, and in warmer parts of Australasia, Asia and Africa. The two appear to overlap in Panama, however, and for this reason they are usually treated as distinct species, though a very close relationship is apparent.

Of recent years there has been increased realisation of a vagrancy potential among the Ardeidae. As evidence for this, one can cite transatlantic crossings by Least Bitterns Ixobrychus exilis (to Iceland and the Azores), a Great Blue Heron Ardea herodias (pages 442-443) and American Bitterns (now about 60 European records); the colonisation of the New World by the Cattle Egret Bubulcus ibis, and Caribbean recoveries of European-ringed Grey Herons A. cinerea and Little Egrets Egretta garzetta. The migratory behaviour of the Green Heron makes it another likely candidate for a transatlantic crossing.

This case was submitted in November 1971 to the B.O.U. Records Committee which, as a result, has now admitted the Green Heron to the British and Irish list, placing it in category B since the record is more than 50 years old (see Brit. Birds, 64: 429, for definitions of categories). The honorary secretary, Dr. J. T. R. Sharrock, has asked me to say that the committee will be glad to re-examine other old records where documented cases are presented; normally these will need to include at least indirect evidence of meteorological conditions at the time of occurrence.'

Admitted nationally in their Eighth Report as the first for Britain (BOURC (1974) Ibis 116: 578).