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| Dodgy wildfowl – give them a chance! http://lbcarchive.co.uk/forum/viewtopic.php?f=22&t=18570 |
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| Author: | Matthew Harrison [ Thu Feb 14, 2013 6:51 pm ] |
| Post subject: | Dodgy wildfowl – give them a chance! |
This isn’t a short article, but if you’re prepared to stick with it, I hope you will find it interesting! So grab a cuppa and read on. The inspiration for writing this came from the Barnacle and Ross’s Goose flock I witnessed at the Nene Mouth recently. Perhaps like most birders my instinctive reaction was “they are escapes”, and no doubt they probably were, but should we jump to such a conclusion so quickly unless we can prove otherwise? Some species are always overshadowed by the evil ‘E’ word – Escape! or other such derogatory words such as ‘plastic’, ‘dodgy duck’ or ‘fence hopper’. They pose a dilemma – do we claim them as wild? Should they be reported? More often than not it’s just easier to dismiss them altogether. But is this fair? Well here are some thoughts on two species which come under close scrutiny when making an appearance in a ‘wild state’ within the County (and beyond). Barnacle Goose - There are three discreet populations of the species native range. The Greenland population which winters in western Britain and Ireland, largely on Islay; The Svalbard population which winters on the Solway Firth and the North Russia/East Baltic population wintering in northwest Europe, predominantly in the Netherlands (although occasionally making it to the British east coast, accompanying other goose species during cold weather influxes). In addition to the above there is a well established naturalised population in the UK, (with an estimated population of 2,700 individuals in 2011) from which there is an increasing number of breeding pairs. In Lincolnshire a feral population on the Humber which developed from an injured pair in 1975 numbered 634 individuals in September 2009. These populations do of course cloud the issue somewhat when trying to assess the movements of potentially wild birds. A prime example of this is of a bird which arrived at Frampton Marsh on 24th April 2010 which had been ringed near Roxton, Bedfordshire in July 2005 and in the intervening period had visited 9 counties as far afield as Wiltshire, Powys and South Yorkshire before arriving at Frampton. Birds not associated with cold weather influxes, or making an unseasonal appearance are always going to be suspect. Bear in mind the following however. A single Barnacle Goose at Lound, Suffolk in April 1993 and another at nearby Fritton Lake, Norfolk in June 1993 (which was still present in 1998 when it bred with a female Barnacle Goose and raised 5 goslings) would surely be considered escapes, or at least feral birds, and most likely dismissed. The former, however, had been ringed in Svalbard in 1986 whilst the latter bird had been ringed in Sweden in 1989 so was from the Baltic population. At least the next record should be easier to decipher. A lone Barnacle Goose watched feeding with domestic animals and captive birds at Bessingham (17 miles north of Norwich) on 15th April 1986 was surely an escape and perhaps not even worthy of reporting? Except for the fact that it had been ringed in Donegal, Ireland, just 5 months earlier (in November 1985) and so was presumably from the Greenland population! Still sure that all these birds we are seeing are feral/escapes? Snow Goose - Breeding throughout North America, two races occur. Lesser Snow Goose winters along the Gulf coast of the USA, with more western populations occurring in southern and western regions of the southern USA, while the Greater Snow Goose is found along the Atlantic coast of the USA. Although Lesser Snow Goose is more numerous, Greater Snow Goose is often considered the more likely for vagrancy due to its more easterly distribution. Goose flocks certainly act as a carrier for rarer species, and any Snow Goose seen in the UK accompanying Icelandic Greylag, Barnacle or Pink-footed Geese is likely to be considered a genuine vagrant. . However, the true status of most birds in the UK is difficult to establish as some are undoubtedly escapes from waterfowl collections or offspring from feral populations. Perhaps more than any other wildfowl species that is capable of arriving on these shores as a genuine vagrant, Snow Geese perhaps fall victim to being tarnished with the escape brush more than most. Should we be so dismissive however? In the UK, the Naturalised Goose Survey 2000 revealed a total of 86 individuals at 17 sites, although this total did not include the self-sustaining population in Argyll. In 2010/11, WeBS reported the presence of Snow Geese at 19 sites, with most records being of one or two birds; with the exception of Fairburn Ings where 22 were observed. A self-sustaining flock of feral birds exists on the island of Coll in Argyll, which has numbered between 25 and 45 birds in recent years. Many of this flock were colour-marked in 2002, but no records away from the immediate vicinity of Coll have been subsequently reported, suggesting that records elsewhere in the UK do not relate to birds from Coll. Occasional breeding also occurs elsewhere but reports seem to be genuinely few and far between. The British population estimate of feral birds in 2011 was just 180 individuals. On this basis, presumably escapees account for most, if not all, of the other reports. Or do they? A Snow Goose shot adjacent to The Wash at Dawsmere (near Gedney Drove End) on 2nd December 1978 which had been ringed as a juvenile in a wildfowl collection near Oslo, Norway on 20 July 1976 certainly does not make assessing records any easier and just shows the distances escaped wildfowl can travel. Likewise a flock of 6 Snow Geese seen in Orkney in April 2012 included a bird carrying a darvic leg ring. This bird had been ringed as a gosling in Neuss, Dusseldorf, Germany in June 2009 (amongst a feral flock of Snow Geese) where it remained until April 2010 amongst a flock of 70 birds. In January 2011, it turned up with 9 others on a canal in the middle of Utrecht, Netherlands where it remained for a month before next being seen a few miles north of Koehool, Freisland, Netherlands with 83 others! It then returned to Utrecht in November 2011 (as part of a flock of 6) before next turning up on Orkney on 22 April 2012. Orkney is approximately 1000km from where this particular bird was originally reared. As part of a feral population this bird does avoid the escape category however! And let’s not forget the record of a flock of 18 Snow Geese (including 4 first-winters and 1 blue morph) which were observed flying down the Thames at Broadness and then later seen at Cliffe, (Kent) on 1st March 1980. What were presumably the same birds were then seen at Andijk, Noord-Holland, Netherlands between 18th and 26th April 1980. Surely escapes or feral birds bearing in mind the size of the flock and the time of year? Would much more have been made of such a sighting had one of the birds not been colour ringed which indicated it was a male Lesser Snow Goose ringed as a gosling at La Pérouse Bay, Manitoba, Canada in 1977?! Wild Snow Geese do occur! Should we really dismiss sightings of this (and some other wildfowl species) so freely? Perhaps they deserve to be taken more seriously. Let’s not forget that Snow Goose appears in Category C2 of the British List – (Naturalized established species – species with established populations resulting from introduction by Man, but which also occur in an apparently natural state) as well as Cat A (Wild State) and Cat E (Escapes). Perhaps C2 may be more appropriate than E for many records – and that means they are tickable on your list! Unless their escape origin can be proven should we not treat any potentially suspect wildfowl that is fully winged, have no rings, are in excellent condition, and are perhaps just a little wary as ‘probably wild’ rather than ‘likely escape’? As the above records show, in the bird world things may not always be as they seem and we should always expect the unexpected. Matthew |
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