SHAG IN GREATER MANCHESTER

by Ian McKerchar

Above: 1st winter Shag at Withins Reservoir by Paul Wilson

 

This article arose when I received the remarkable series of photographs taken by county photographers Jill Islam and Paul Wilson, a sequence of images that would have been outstanding from anywhere around the coast of the UK but to have come from a reservoir thirty miles inland in Greater Manchester where Shag remains a county rarity makes them even more exceptional.

This first winter individual was seen briefly at Elton Reservoir and then at it's 'stone's-throw' close neighbour reservoir Withins but the full details of it's occurrence will no doubt (and quite rightly) be published in the annual county bird report for 2008. This short article is intended to give Jill and Paul's wonderful images the full attention they deserve and to utilise them to highlight the structural identification differences between Shag and Cormorant.

Above: 1st winter Shag at Withins Reservoir by Jill Islam

Shag has acquired more than 25 records in Greater Manchester although only one of those previous records was in August and the full detailed analysis of county Shag records can be found here. Oddly, it appeared that the 2008 Greater Manchester bird occurred during an inland influx of the species throughout the UK during August, which up to the time of writing this article (25th August 2008), had risen to a total of atleast 27 inland birds throughout the UK, including a remarkable 6 individuals together at Draycote Water in Warwickshire! An occurrence of this size seems not to have been mirrored in any August in previous years since the year 2000 at least, although 2005 experienced a somewhat smaller influx and 9 Shags together at Holme Pierrepoint, Nottinghamshire in August 2007 was particularly outstanding.

Above: 1st winter Shag at Withins Reservoir by Jill Islam

This Withins Reservoir individual was staggeringly confiding at times (hence these terrific photos!) but that isn't as usual as one might expect, even for an inland bird and one individual in Birmingham City Centre, West Midlands in December 2005 was similarly as confiding as this bird, spending it's time on a canal (surrounded by buildings on all sides) right in the city centre and was found frequently waddling along the towpath!

Ageing immature Shags isn't necessarily all that easy as they show considerable variability within their age groups and undergo almost continuous body moult from their first autumn until they acquire the full adult plumage some 2 (and occasionally 3) years later but this bird's combination of rather uniformly 'new' upperparts (lacking any contrast of new and old feathers), combined with the yellowish-white iris (with a little hint of green already) and pointed longest scapulars would appear to age this individual as a 1st winter, as juveniles largely lack the metallic green 'gloss' so evident on the head and neck of this bird.

Above: 1st winter Shag at Withins Reservoir by Jill Islam

Most often, Shag will be separated from Cormorant by it's combination of size, structure and jizz, being smaller and slimmer although observers should be aware that female Cormorants (particularly of the race sinensis) can appear very small and particularly Shag-like, especially if seen without any comparison. Without these jizz features, as we have in isolated images such as these, we can concentrate on the more delicate structural features of the head and bill particularly and below, we can compare them to similar photographs of Cormorants of the race carbo.

   

Above: Left, 1st winter Shag at Withins Reservoir by Jill Islam and right, 2nd winter Cormorant at Seaforth by Ian McKerchar

In the two images above, the structural features of the head are prominent when compared against each other, namely:

  1. Shag's much steeper forehead against Cormorant's lower, more evenly sloping forehead (but beware of Shag's forehead profile appearing less steep when diving). The highest point of the crown on Shag is clearly just in front of the eye, whereas in Cormorant it is (under normal conditions) well beyond the eye at the rear of the nape.

  2. Shag's more evenly parallel bill, looking longer and slimmer compared to Cormorant's more tapered bill which appears slightly more wedge shaped.

  3. Note the Shag's eye is surrounded by feathered skin and appears isolated as apposed to the Cormorant's eye which is surrounded by bare skin, obviously yellow in this instance but darker feathering on the lores can confuse maters, especially at range, when it can appear more Shag-like.

  4. The bare skin below the eye extends rearward only along the gape line on Shag, projecting beyond the eye but remaining feathered beneath it, whereas on Cormorant the facial area below the eye to the chin is extensively bare-skin and obviously yellow or orange coloured (note that Shag never shows any orange colouration on the facial skin).

  

Above: Left, 1st winter Shag at Withins Reservoir by Jill Islam and right, 1st winter Cormorant at Pennington Flash by Jon Taverner

The above images once again clearly demonstrate the structural features of the head as outlined above but note that in these images the neck of the Shag appears thicker than that of the Cormorant which looks much slimmer (the opposite should be true!), no doubt much of this is due to the two images not being to scale but the Cormorant has also been involved in actively diving and the plumage is still wet giving a temporarily sleeker and slimmer appearance to the neck.

Above: 1st winter Shag at Withins Reservoir by Paul Wilson

The above image illustrates how the shape of the crown can alter when wet after actively diving, compare it to the image above that of the Cormorant and it looks very similar in shape but this is only ever a temporary appearance in Shag. Note how isolated the eye looks, clearly surrounded by dark feathering.

Above: 1st winter Shag at Withins Reservoir by Paul Wilson

Although not possible to make out in the above image, Shag's slimmer appearance is notable in flight too (particularly against Cormorant's heavy in-flight appearance with larger head and thicker neck) and has a straighter neck than the more obviously kinked neck of Cormorant. Shag actually has only 12 tail feathers and Cormorant 14 but attempting to utilise this feature in the field is nigh on impossible and it is included here more for interest than as a major identification factor but the above image does however admirably display the distinctive pale panel across the forewing on 1st winter Shags such as this individual, a feature due to feather wear on the wing coverts.

Above: 1st winter Shag at Withins Reservoir by Jill Islam

 

Acknowledgements

I would of course like to thank Jill Islam and Paul Wilson for taking these striking images in the first place and for allowing me to utilise them in this article and to Simon Warford for getting Jill's images to me and Jon Taverner for the use of his Cormorant image.

 

References

Identification Guide to European Non-Passerines, BTO Guide 24, Kevin Baker.

 

Ian McKerchar, August 2008

 

 

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