Tundra Peregrine

Probable Tundra Peregrine on the Amble Marshes

Colin Selway

This individual was first seen at Amble Marshes Cornwall 12th December 2010 and first reported as a Lanner Falcon. I watched it for the first time at Amble Marshes on 2nd January 2011 at a fair distance, near the back of the reserve, and I could well understand why Lanner was suggested. My first impressions were, of a large, long-tailed, powerful falcon, with wings very long but broad-based, showing a very whitish head/nape and underparts, darker upperparts with a clean dividing line level with the wings across the lower nape. I thought it could even be a Saker or Saker x Peregrine hybrid, especially as the two central tail feathers appeared to show a slightly different density or shade of barring.

I later found a reference to a similar difference documented by Clayton M White in his description of immature Tundra Peregrine Falcon (tundrius); “Diagnosis and Relationships of North American Tundra-Inhabiting Peregrine Falcons”, The Auk, Vol 85, April 1968. This feature can also be seen on some immature birds of the nominate race. Later, seeing the Amble bird more often, and getting more close-up views some showing the wing-tips reaching to the tip of the tail, the legs and feet to be a dull yellow (the thicker section of the toes nearest the claws being the brightest yellow) and the outermost primary longer than the third, all helped to confirm immature Peregrine Falcon, but the jizz and behaviour was strikingly nothing like any Peregrine I have watched before. As for the appearance, while I fully accept that plumage in this group is subject to age, sex and a great deal of individual dependent variation, certainly in the local population that variation tends to range within definite limits, for me the Amble bird stood out as a typical example of an immature Tundra Peregrine (tundrius) ticking all the right boxes. The white forehead, distinctive head pattern and colour with a dark stripe running behind the eye, below and parallel to a much lighter superciliary stripe, a light break running from the corner of the gape though the malar/moustache, not always obvious but sometimes unmistakable, extensive whitish-buff edgings to mantle and upper-tail coverts, narrowish linear streaking to the central underside, very light streaking on trousers, very light lower belly and undertail coverts with some light barring to longest outermost undertail coverts only.
I cannot stress enough the caution that should be applied to accessing digital images particularly of this Falcon, in the field, even in very good light this individual always, in contrast to the local immature Peregrine appeared cold and lacking any rufous or warm tones, a whitish-buff at most, a bit like viewing a normal plumaged Buzzard next to a Rough-legged . Not every photographers main motivation is to try to record as accurately as possible a rare race, quite understandably the majority, especially if they have a good image, try to compose, with no intension to mislead, the most pleasing picture to the eye possible, most often this is achieved automatically by the computer software.

As this Falcon is extremely unlikely to be generally accepted as an immature tundrius, plus the occurrence of a dark headed immature, or adult tundrius phenotypes is even more likely to be overlooked, the best anyone can do is to describe and record for possible future reference. Indeed time is fast running out for anyone to be able to prove tundrius as a occasional migrant or winter visitor to the UK.
Only recognized as a sub-species in 1968 by C M White, the rapid dilution of genes from introductions, repopulation programmes using a mix of races, plus escaped falconer’s stock means contamination is inevitable on both sides of the Atlantic. It may help to support the case for considering the Amble Marshes Tundra Peregrine, in that, there appears to have been a possible small influx of phenotypically similar immature Peregrine into the southwest of England this winter, plus a record of a similar falcon following a ship out of sight of land between New York and Miami, one in the Port of Rotterdam on 19th October 2010, and one at Chew Valley Lake on 28th December 2010. These last three records are all within the plumage variation range of the nominate form peregrinus. The first of those records was almost certainly closer to America than to the mid Atlantic, and merely underlines the fact that migrating Peregrine Falcon do fly over open ocean, they would have no choice migrating from Greenland south, and for a very long time the North Atlantic has been dotted with football pitch sized floating platforms, some possibly with available prey species on board, certainly enough time for generarations of adapting highly migratory Peregrine to successfully utilise these stepping stones as a migration strategy, in much the same way and timescale as the nominate form, plus some races have adapted well to life in urban areas.

The four remaining records in Cornwall and the Isles of Scilly this winter (Tresco, Isles of Scilly from 6-26th October 2010, Treen, Cornwall, 17th October 2010, Amble Marshes, Cornwall, 12th December 2010 to 26th January 2011 and Davidstow, Cornwall, on 16th January 2011) cannot be in my opinion be so easily dismissed as merely odd untypical Peregrines, there are good photos in circulation of the first three individuals and a poor video plus a good description of the Davidstow bird. I remain convinced that the Davidstow individual is a different bird although it was recorded only approximately 14 miles from the Amble Marshes bird it appeared to be much lighter below with a slightly different nape pattern. It’s true that colours can deceptive in a poor quality video but a structural difference can be seen in the tail end corners, the Amble Marshes bird having a more clearly worn tail end showing sharper Kite like corners, The Davidstow bird still with some wear to the tail tip though showing much more rounded corners and more even brighter barring across the upper tail. As for notes on behaviour I can only provide details for the Amble Marshes Falcon except for Derek Julian’s account of the bird at Davidstow, he noted that it was perched on an exposed pine branch and it flew off in pursuit of another Peregrine Falcon, appearing to drive it away. Tony Blunden describing his Treen sighting as ‘a slow fly-over’. It was reported of the Tresco Falcon sometime during its stay on Scilly, that it killed and consumed a Kestrel!

I must have watched Amble Marshes falcon this winter for a total of between two and a half to three hours from the Tower Hide, each time the falcon arrived it always, without exception, flew in at low level causing panic among the Duck and Waders. The duck, mostly Wigeon and Teal, would settle on the open areas of water and although they would call desperately they appeared to stay still as the Falcon flew very low overhead checking the flock over sometimes briefly hovering. The waders would adopt a different strategy, they would bunch up and fly high sometimes landing a safe distance away on the marsh, sometimes flying off towards the estuary. Both proved to be a successful strategies as I only once observed the Falcon attack a Black-tailed Godwit which was at low level, as it came in to land. It was then chased off at high speed out of sight towards the estuary just above the hedge tops. In the whole time of watching this individual I never ever observed it to be higher than 60 feet, with all short banking glides noting that the wings were held flat with primaries pointed slightly upwards, and it always departed the Marshes in the same fashion, Sparrowhawk like, just above the hedge tops towards the Camel Estuary. My only sighting of this falcon away from Amble Marshes, but still on the Camel Estuary was at Treraven Meadow on 17 01 2011 where it acted in exactly the same way. But most of its time observed on the Amble Marshes it spent perched on flat open ground, in an area of flood plain with the river Amble running through the centre, a grazed field with open areas and patches of Juncus. This behaviour seemed a little odd as there was certainly no shortage of low fence posts, large rocks or tree stumps providing, you would think, ideal lookouts. On the ground it appeared to be either watching the wildfowl or searching for food while walking on the ground, it did manage to catch a small unidentified rodent and swallow it, in fact it’s the only thing I did see it actually kill. The only other prey that I watched it come close to killing was Herring Gull! In all I witnessed three different Herring gull attacks all appearing not to be instigated by the Gulls, but rather by the falcon focusing on a particular Gull that happened to be in range, it’s hard to say if the Falcons motivation was due to hunger or annoyance but each attack involved a short straight chase just above the ground ending in the Falcons talons just inches from the Gulls neck, on one occasion knocking body feathers out of the neck, serious attack or not there’s no doubt that Gulls took it very seriously screaming in distress then departing the scene. There was absolutely no evidence of the Gulls mobbing this falcon.

At the moment the minimum requirement for a tundrius acceptance would be nothing less than a ringing recovery, at best all there is to do is to describe interesting records of individuals or groups, differing in plumage or behaviour, be it suspected sub-species or geographic cline, from the nominate form peregrinus. As this individual falcon, and possibly a second! are still being seen intermittently around Amble Marshes and Davidstow (last date at both sites on 3rd January 2011) allowing anyone really interested enough a chance to see this bird for themselves, and perhaps to draw their own conclusions. I just thought it would be a novel idea to post some observations now, rather than several months later, after the falcon or falcons had departed.

Photos by Adrian Langdon and Bob Mitchell

Update 12th February 2011

The Probable Tundra Peregrine was seen again at Amble Marshes 11th February 2011 when it was present for most of the morning at least. I watched the bird for over two hours and in that time I watched it chase and kill a Starling. From its position perched in the middle of a large field the Falcon flew directly towards a small flock of Starlings and took one cleanly, a few feet above the ground. It then completely consumed it’s kill on the ground, occasionally being tormented by a small group of Carrion Crow. They eventually drove the Falcon from the ground into a small tree, something I had never observed before with the original observations. With plenty of time to observe this last bird more closely I could detect some apparent differences in its appearance from the original Amble Marshes Falcon, including, the nape appeared more heavily marked dark, the tail end less heavily abraded and the uppertail more boldly barred, legs/feet evenly coloured dull yellow and showing no bright yellow at all, this leading to the conclusion that this later falcon (from 3rd February 2011) could be the possible Tundra Peregrine first noted perched on tree at Davidstow!

Last sighting

A Probable Tundra Peregrine was noted over Wadebridge on 12th February 2011 when it then flew towards the Estuary at 10:10.

It may appear a little odd that I have not mentioned before the possibility of calidus (Palearctic Tundra) especially as there appears to be, as yet no reliable established criteria for separating it from the (Nearctic) tundrius, in fact some people hold the view that the apparent variation in tundrius may be blocking calidus from the British list. I take the rather simplistic view that the Amble Marshes Peregrine appears to show the longest wings of any Peregrine noted by me, and tundrius has the longest migrations of the group, plus I feel it much more likely that a small influx of these phenotypes into the West of England only, would be much more likely to be from the New World, in much the same way as we appear to get more records of Greenland white-morph Gyr Falcon than of the Norwegian grey-morph. Then while there is Bergmann’s Rule, (larger sizes normally found in colder environments), it appears that only Peregrine Falcon from the Old World conform to that rule, and although being quite large you could never describe the Amble Marshes Peregrine as being compact, some observers have even described it as Kite like at times!