The Pitsford Black-necked Grebe

This Black-necked Grebe has been present at Pitsford Reservoir since I first found it on 14th September. Black-necked Grebe has been thin on the ground in Northants this year and it’s only the second one to be discovered in the County in 2012. I took some rather poor video footage today while the bird was off the dam. My attempts at videoscoping can only get better … 🙂

Latest Reports: email and text alerts

Some important news concerning the receipt of email and text alerts from Northantsbirds has emerged today. For those using ifttt.com as a conduit for receiving news from Twitter by email or SMS this organisation has announced that, from 27th September 2012, it will no longer offer this service as a result of Twitter policy changes that will affect how applications can interact with Twitter’s data. As a result of these changes, ifttt.com will be removing all Twitter ‘triggers’, disabling the ability to receive tweets by email and SMS. In short, anyone who has elected to use this service, by creating ‘recipes’ using the #Northantsbirds hashtag, will no longer be able to receive latest reports from Northantsbirds by this method.

This does not affect anyone who is receiving text alerts direct from Twitter (i.e. not via ifttt.com). So, from 27th September, the only method of receiving immediate Northantsbirds news will be by SMS text alert, directly from Twitter, to a mobile phone – and this can’t be a bad thing! To receive these alerts simply follow @bonxie on Twitter, register your mobile phone details on your Twitter account and then select ‘turn on mobile communications’ from the dropdown menu next to the ‘following’ button on the @bonxie profile page.

For those interested, a full explanation of ifttt.com’s changes to the way it will be operating with regard to Twitter can be found at tinyurl.com/bn4resq 

The Daventry ‘Blue-winged Teal’

The discovery of a female Blue-winged Teal at Daventry Country Park yesterday morning looked set to initiate a local twitch as well as attracting more birders from further afield. Initially located at the south-eastern end of the reservoir it eventually moved toward the dam, where it remained for the rest of the day, favouring the small Lovell’s Bay directly opposite the ranger’s office.

With the arrival of more birders, however, it became apparent that some observers were not entirely convinced that this individual was, in fact, a ‘pure’ Blue-winged Teal. With the bird showing well – at times down to around fifty metres – a feather-by-feather analysis was soon being undertaken as this individual’s parentage was thrown into question.

Blue-winged Teal ‘with presumed Shoveler genes’, Daventry CP, 17th September 2012 (Allan Maybury)

The feature which cast the most doubt on the birds ‘purity’ was the structure of the bill. It appeared too long and too broad and spatulate for a Blue-winged Teal, recalling that of a Shoveler, a species with which Blue-winged Teal is known to occasionally hybridise.

Blue-winged Teal ‘with presumed Shoveler genes’, Daventry CP, 17th September 2012 (RW Bullock)

Suddenly the ‘H’ word was being bandied about and a number of birders formed the opinion that this bird must, therefore, be a Blue-winged Teal x Shoveler hybrid.

Blue-winged Teal ‘with presumed Shoveler genes’, Daventry CP, 17th September 2012 (RW Bullock)

This speculation was further fuelled by other features which were believed to be anomalous, i.e. a dull yellowish base to the underside of the lower mandible and, just visible (when blown up) in the photographs above, some yellow/ochre pigmentation at the base of the upper mandible. The legs and feet, too, were thought to be a shade too ‘orangey’ for Blue-winged Teal. Apart from these apparent bare part anomalies, however, there was nothing else radically wrong with the bird.

It appeared to be an adult (juveniles/first-winters have dull, greyish legs) and the thin white border behind the blue coverts, along with the dull green/blackish speculum, indicated it was a female. The remainder of the plumage (loral spot intensity, supercilium and eyestripe extent and prominence) and the dark iris colour were spot-on for Blue-winged Teal, as was the overall cold plumage tone, suggesting an absence of Cinnamon Teal genes in this individual.

Blue-winged Teal ‘with presumed Shoveler genes’, Daventry CP, 17th September 2012 (RW Bullock)

I trawled through a number of  images on the internet and found some which were good matches for leg colour (it is nowhere near as orange as that of a Shoveler – see the video below for comparison) and it would appear that, according to BWP, the bill colour is not ‘wrong’ for Blue-winged Teal at all. So, is it really a hybrid or is it conceivably a Blue-winged Teal with an abnormally large bill? Did some Shoveler genes get in there somewhere a few generations back? It surely cannot be a first-generation hybrid with so few Shoveler-type characteristics evident. The internet search also revealed a variation in bill size (drake Blue-winged Teals are known to have larger bills than females) although, admittedly, nothing quite as large as the bill on the Daventry bird … Images of a presumed Blue-winged Teal x Shoveler hybrid can be found here while a gallery of pure Blue-winged Teal images can be viewed here. When I was watching the bird in the early evening it was feeding constantly, either alone or with one or two Shovelers. Both the teal and the Shovelers engaged in a ‘hostile pumping’ display when they got too close to each other, i.e. a feeding territorial display (see video), which is said to be common behaviour among ‘blue-winged’ ducks. Despite rumours to the contrary it was fully-winged as is illustrated in the accompanying images.

VIDEO Blue-winged Teal ‘with presumed Shoveler genes’, Daventry CP, 17th September 2012 (Mike Alibone) 

This very interesting and instructive individual is worth seeing if you get the chance.

It is also worth pointing out that Blue-winged Teal remains a true rarity in Northants with three records comprising an adult drake at Ditchford GP on 13th April 1979, a female or eclipse drake at Thrapston GP from 25th August to 14th September 1985 and an adult drake at Earls Barton GP from 25th February until 1st March 2001.

Many thanks to Bob Bullock and Allan Maybury for supplying the stills used to accompany this post.

Phylloscopy

This morning I spent some time at Stanford Reservoir with the Stanford Ringing Group. With summer all but over, the number of birds trapped was relatively low with 48 new birds of 13 species ringed (25% of which were Swallows) and 18 retraps of 11 species.

When not singing or calling, two of these species, Chiffchaff and Willow Warbler, present perennial ID difficulties for many birders in the field but not, of course, in the hand where biometrics and key features not obviously visible to field observers make separation easy. However, one of these features – namely wing structure – can be used in the field, if the bird stays still long enough for it to be assessed! Willow Warbler has longer wings than Chiffchaff, which is illustrated well in the below set of photos of two of the individuals trapped at Stanford this morning.

Wing comparison Willow Warbler (left) and Chiffchaff, Stanford Res, 1st September 2012 (Mike Alibone)


These two photos show the diagnostic emarginated 6th primary of Chiffchaff and its absence in Willow Warbler – not visible in the field, of course – but in the image of Chiffchaff the short first primary is tucked away and not visible and the second primary is barely visible behind P3.

Willow Warbler (left) and Chiffchaff folded wing structure, Stanford Res, 1st September 2012 (Mike Alibone)

The above two show the difference in length of primary projection: in the Chiffchaff it is little more than half the length of the visible tertials while Willow Warbler has a much longer primary projection – often the same length as the tertials and at least three quarters the length in the shortest instance (click on image to enlarge).

Now have a go and apply this to the bird below, recently photographed by Doug McFarlane in Moulton.  See here for the correct answer!
The final image is a bright juvenile Willow Warbler which, with its vivid yellow upper breast and whitish belly, is a pitfall for the unwary, sometimes accounting for erroneous reports of Wood Warblers in autumn …

Juvenile Willow Warbler, Stanford Res, 1st September 2012 (Mike Alibone)

Many thanks to John, Mick, Adam and Dawn for putting up with me and allowing me to photograph ‘their’ birds at Stanford this morning!