Category Archives: Birds

The Uskmouth Savi’s Warbler

A Savi’s Warbler (Locustella luscinioides) at the RSPB’s Uskmouth Nature Reserve has now entered the third week of its stay. The bird was found by Mathew Meehan and is the first record for Gwent. It is holding territory in a small strip of reedbed in the centre of the reserve, flanked on one side by a track and on the other by open water, so (unusually for this species) it is quite easy to observe. If visiting, please keep to the paths: as well as the Savi’s Warbler, nesting Bearded Tits (Panurus biarmicus) and Cetti’s Warblers (Cettia cetti) are present in the same area.

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Savi’s Warbler, 1 June 2014, Uskmouth Nature Reserve, Martyn Hall (www.martynhallphotography.com)

If the physical appearance of Savi’s Warbler is a little dull, its song certainly isn’t: it sounds like a loud, prolonged cricket. I emphasise loud: on my first visit, I could hear the bird from at least 100 metres away as I approached. Click here to listen to a recording of the Uskmouth bird by Darryl Spittle.

Savi’s Warbler is at the northwestern end of its world range in Britain, and numbers have fluctuated considerably since it was first discovered here in the early 19th Century. Back then, it bred in Norfolk and Cambridgeshire, but with drainage of the fens, this population died out by around 1850. It remained a rare migrant for the next 100 years, but then established a breeding population again, initially in Kent, then in Norfolk, Suffolk and a few other southern and eastern counties, although still in tiny numbers: the peak population was of c.30 singing males at a total of c.15 sites in 1977-1980. Numbers have since declined, to the point where ten singing males constitutes a good year.

Most of our local birds have occurred on the Somerset Levels, where around a dozen have occurred, with two clusters of records: four birds at the gravel pits around Bridgwater between 1970 and 1988, and five birds in the Ham Wall/Meare Heath area between 2005 and 2010. Chew Valley Lake has had four, the last of which was in 2001. In Gloucestershire there have been just two: at Frampton in spring 2001, and at Coombe Hill Meadows in 2013. Wiltshire has also had just two, at Coate Water, Swindon in May 1965, and at the Cotswold Water Park in 2006. Almost all of these birds have been singing males in spring, so no doubt other individuals have occurred undetected. With the increase in records from the Somerset Levels in the last decade, there’s perhaps a good chance that Savi’s Warbler will become a regular breeding bird here one day.

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A Siberian Chiffchaff on a Bristol dung-heap

Common Chiffchaff (Phylloscopus collybita) is a leaf-warbler familiar to birdwatchers in Britain, as a common summer visitor, and in much of the country as a winter visitor in small numbers. Its eastern cousin tristis, Siberian Chiffchaff, also regularly winters in Britain, and there’s currently one in Boiling Wells Lane, at the north end of St Werburghs. The stream from which the lane gets its name, and a nearby dung-heap, are attracting plenty of insects, keeping our Siberian visitor loyal to a very small area. Here’s a photo:

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A lot of confusion surrounds the status of Siberian Chiffchaff in Britain, more of which below, but they are pretty distinctive birds, especially if you have the opportunity to compare one with Common Chiffchaffs, of which there are up to four at Boiling Wells currently. Siberians are paler birds, particularly on their underparts, which are whitish, lacking the yellowish-buff colours present on Common Chiffchaff. The upperparts are pale grey-brown, usually without the green tones of Common Chiffchaff, although the flight-feathers and the tail can be finely edged with green. Usually there is a warm buff colour on the cheeks and breast-sides, and there can often be a narrow pale wingbar. The bill and legs are black and so are conspicuously contrasting compared with the pale plumage. Finally, both songs and calls are different: the St Werburghs bird gives the typical call of Siberian Chiffchaff, a soft single-syllabled ‘peep’, neither rising nor falling, different from the rising, slightly disyllabic ‘hueet’ call of Common Chiffchaff. If it’s a male, it may start singing later in the winter: instead of the repetitive ‘chiff … chaff’ song, Siberian’s song has a more varied structure to it.

The confusion I mentioned above has a long history. First, in the 1950s and 1960s, several SIberian Chiffchaffs were mistaken for Greenish Warblers (Phylloscopus trochiloides), something that seems hard to believe today, with improved knowledge and better optical equipment. More recently, there has been a wide-ranging debate about the identity of non-calling birds, especially those which differ from the typical appearance described above. Midlands birder Alan Dean has highlighted several such birds which he terms “grey-and-white chiffchaffs”, and believes that these are not Siberian Chiffchaffs, but either eastern Common Chiffchaffs or the result of hybridisation where the two meet.  This has caused many birders to doubt the identity of many of the birds they’ve seen.

Thankfully, things may not be as bad as Alan suggests. Birders based in Poole, Dorset have been studying their wintering chiffchaffs, and concluded that at least some of the birds which do not conform to the typical appearance still call and sing like Siberians. More recently, ornithologists in the Netherlands looked at the DNA of birds trapped for ringing, and discovered that not only did birds identified confidently as Siberian Chiffchaffs have the right DNA, so did a large number of other birds, all of which had been tentatively identified by their ringers as Scandinavian Common Chiffchaffs (Scandinavia is one area the “grey-and-white” birds have been thought to come from). Interestingly, none of the birds in this study had DNA which matched birds from Scandinavia, even though the Dutch ringers had specifically been looking out for them, and all of the normal-looking Common Chiffchaffs trapped were just that.

There has also been a study in western Russia, looking at if and how frequently the two hybridise. The answer? Yes, just like us humans, some chiffchaffs are confused about chiffchaffs and hybridisation does occur. However, it only occurs in a narrow zone some tens of miles wide where the two populations overlap. West of this for several thousands of miles are normal Common Chiffchaffs, while normal Siberian Chiffchaffs are found east almost all the way to the Pacific Ocean. Numerically, hybrids are so rare that they can’t really be the cause of Alan Dean’s puzzle.

There are dozens of other Phylloscopus warblers in Europe and Asia, and many of these are difficult to tell apart visually, but have distinctive calls and/or songs – indeed, several new species have been described based on this in the last twenty years or so. Siberian and Common Chiffchaffs seem to be another one of these species-pairs. Historically, Siberian Chiffchaff has been considered a geographical race of Common Chiffchaff, however given what we now know this is not really appropriate. Because of the narrow hybridisation zone, they are probably best considered “semispecies” (biological jargon which means that, although not everything’s completely sorted out in the overlap zone, evolution has basically done its job and the two are on separate future trajectories).

I did a little bit of birding PR today with the owners of the dung-heap: they had wondered if all the people with cameras who had been visiting this week were from Bristol City Council and were eyeing up their land for house building. I showed the bird to them and explained why it was attracting interest, and I think they’re now happy that their visitors are all just perfectly normal people who just happen to like looking at birds on dung-heaps. They regularly turn the dung, exposing more of the chiffchaff’s food, so hopefully it will hang around for quite a while.

Here’s a map showing the area the bird frequents:

Uskmouth Reserve’s Penduline Tit

This male Penduline Tit (Remiz pendulinus) is entertaining the crowds at the RSPB’s Uskmouth Nature Reserve, near Newport, at the moment, feeding on dead flowerheads of Bulrush (Typha latifolia), right by the reserve’s visitor centre.

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Eurasian Penduline Tit (to give it its full English name, as there are about nine other species in Asia and Africa) is one of several bird species which have spread northwest from eastern Europe in recent decades. The first British record was in the 1960s, at Spurn, the famous migration watchpoint in Yorkshire, but now almost 300 have occurred here, including several small flocks. There has long been speculation that Penduline Tits might colonise southeast England, but so far it hasn’t happened – and we can say this with a fair amount of certainty as the nest is a conspicuous pouch which is constructed hanging from a tree branch above or close to water, and one of these would surely have been noticed considering how well-watched Britain’s wetlands are.

The Uskmouth bird can be identified as a male by its large black mask, with a rusty bar across the forehead, whitish head, intense chestnut upperparts, and small reddish-brown breast-streaks. Females have a narrow face-mask, pale grey head, paler upperparts and plain underparts, and juveniles have a completely plain pale brown head.

Uskmouth’s bird is the first for Gwent, but there have been several on this side of the estuary (see below), and with the trend towards increasing numbers, plenty more can be expected.

  • Westhay Moor, two birds from January to March 1997
  • Berrow reedbed, three birds in December 1997 and February 1998
  • Shapwick Heath, two birds in December 1999
  • Ham Wall, four birds in January 2004
  • Portbury Wharf, two birds in January 2012

Uskmouth reserve is just west of the small village of Nash, east of the river Usk, south of Newport, and is signposted from junction 24 of the M4 motorway.

People? What are they?

I’m stretching my geographical boundaries a little farther than normal to the northwest with this post, but I think the subject deserves it. This is a juvenile Long-billed Dowitcher (Limnodromus scolopaceus), which turned up last week on Rhaslas Pond, just east of Merthyr Tydfil, and has spent the weekend entertaining birders and photographers at point-blank range. Rhaslas is a small artificial reservoir in the middle of bleak moorland, which goes to show that rare (i.e. lost) birds can turn up anywhere.

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Long-billed Dowitcher is generally thought of as a North American bird and those occurring at this time of year are most likely to have originated in the Canadian Arctic and been brought across the Atlantic by low pressure weather systems. However, there is also a significant population in Arctic Russia, and some Long-billed Dowitchers occurring here, particularly adult birds in late summer, probably come from that direction. The third possibility is that once here, they stay and migrate up and down the East Atlantic flyway, with godwits or other European shorebirds.

There are much better photographic efforts than mine on the Cardiff Bird Club blog. The photo below shows just how close everyone was able to get (the red arrow points to the bird); indeed, while I was there it kept walking towards the photographers rather than away from them.

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Arctic-bred shorebirds have been known on previous occasions in Britain to be just as tame: there was a Buff-breasted Sandpiper (Calidris subruficollis) in Somerset a few years back which allowed an equally close approach, for example. Most famous of all is an Upland Sandpiper (Bartramia longicauda) which occurred on the Isles of Scilly in the 1980s which was so tame it took a worm out of a birdwatcher’s mouth. These birds are invariably juveniles on their first southbound migration and the theory is that because they’ve never seen people before, they don’t associate us with danger: bad news for the individual bird, but great news for birdwatchers.

Little Gulls at Chew Valley Lake

These two Little Gulls (Hydrocoleus minutus) were at Chew Valley Lake this afternoon. Usually, when Little Gulls turn up at Chew, they feed over the centre of the lake, way beyond camera range, but for some reason, these two birds chose to frequent Herriott’s Pool, the small body of water separated from the main lake by the A368.

CVL Little Gull adult CVL Little Gull juvenile

These two are a non-breeding-plumaged adult (left) and a juvenile (right). Little Gull is the world’s smallest gull, much smaller than a Black-headed Gull (Chroicocephalus ridibundus). Adults have deep dark grey underwings, and the pale grey upperwings lack the finger of white along the front edge that Black-headed Gull shows. In breeding plumage they have black hoods and pink-washed underparts. Juveniles have a contrasting pattern of black, grey and white, lacking the gingery-brown tones of juvenile Black-headed Gulls. The black stretches from wing-tip to wing-tip across the back (the bird in the picture above has its wings fully outstretched; when the wings are in normal beating mode, the black forms a ‘W’ shape). Juveniles moult into first-winter plumage later in the autumn, replacing the black on the upperparts with pale grey, but the black on the wings remains, so the W is a good feature throughout the winter (note that juvenile and first-winter Kittiwakes have a similar pattern, but as long as you have a Black-headed Gull nearby for a size comparison you shouldn’t get the two confused).

Little Gulls do not regularly breed in Britain. Their main breeding colonies lie to the east of us, in marshes from eastern Europe and Scandinavia into Russia. They mainly occur in Britain on migration, in April and May, and then again from August to October. Flocks at Chew Valley Lake are usually of single-figures, or occasionally into double-figures. These numbers are typical for large wetland sites in Britain. There are two areas in Britain which regularly attract much large numbers, however: the Mersey coast, and the east Yorkshire coast. The former often attracts hundreds, and the latter has been known to host thousands. Small numbers of (usually first-summer) birds oversummer in Britain, mainly on the east coast, and occasionally make nesting attempts, although so far these have all been unsuccessful. Interestingly, breeding Little Gulls have successfully colonised the east coast of North America in the last hundred years, so the establishment of a British colony may be a possibility one day.

For more information on birds at Chew Valley Lake, Rich Andrews’ CVL Birding website is highly recommended.

Whinchats

I bumped into three Whinchats (Saxicola rubetra) this afternoon at Stockwood Open Space, in the thistly rough grassland between the sports pitch and the main path. One of them was co-operative enough to enable me to get a photo.

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At this time of year, all ages and both sexes of Whinchats look pretty much the same, with a buffy stripe above the eye (the supercilium), dark droplet-shaped markings on the upperparts, and pale orangey-buff underparts. Spring males, however, are boldly marked, with a distinctive head-pattern (a white supercilium and dark cheeks) and the orange on the throat and breast is more intense, like this bird.

Whinchats don’t breed around Bristol: these birds are on migration, south to their wintering areas. After they leave Britain, these birds are likely to move south through France to Spain or Portugal, where they will feed up, ready for a flight across the Sahara to their wintering zone in the savannah from Senegal eastwards; returning birds in the spring are usually seen from the second half of April.

Green Sandpiper

Autumn is here: the first of the post-breeding shorebirds are on their way south. At Slimbridge, while I was watching the Spoonbill, there were at least six Green Sandpipers (Tringa ochropus) feeding on the edges of the same pool. I was going to illustrate this post with my own photos, and then Vic Savery sent me this excellent shot:

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Green Sandpiper, 1 July 2013, Slimbridge, Gloucestershire, Vic Savery (naturenutz.net)

Green Sandpiper is the earliest of our sandpipers to appear on southbound migration, always being seen somewhere locally from the end of June onwards, so no need to panic about winter being on the way just yet. Any freshwater wetland with reasonable areas of exposed mud will be graced by Green Sandpipers over the next few months. The birds turning up at the moment are adults, whereas juvenile birds will occur from August onwards (a pattern common to most migrant shorebirds). Green Sandpipers also overwinter in the region in moderate numbers, tending to inhabit shallow slow-flowing streams and ditches and marshy sites.

Green Sandpipers nest in bogs from Scandinavia eastwards through Russia. Unusually for a shorebird, they nest in trees, in disused birds nests. Occasionally, pairs nest in Scotland. A lookalike species, Solitary Sandpiper (Tringa solitaria), replaces Green Sandpiper in North America. They have occured in southwest England after Atlantic storms in autumn several times, usually on the Isles of Scilly, but there was one in Devon a few years ago, so it’s possible that one could turn up near Bristol one day.

Here are a couple of my own Green Sandpiper photos as well, showing a Slimbridge bird in some different poses, and highlighting how birds can look different in different lighting conditions. You can also see, by looking closely at individual feathers, that this is a different bird from the one Vic photographed.

 Green Sandpiper Slimbridge 28 June 2013 b  Green Sandpiper Slimbridge 28 June 2013 a