Category Archives: Colonising species

Roesel’s Bush-cricket

It’s the time of year when orthopterans are out in force just about anywhere with any decent vegetation. There are four families represented in Britain: grasshoppers are common and familiar; the larger bush-crickets (which many people just refer to as “crickets”) are less conspicuous but still common; then there are the groundhoppers, which take a bit of searching for, and the true crickets, which are just downright rare. This diversity is the reason for going ever-so-slightly jargony with that first sentence: there isn’t really a single good shorthand name, the best compromise probably being “Grasshopper and crickets”.

They are quite an easy group to get to grips with, as there are only about 30 species in Britain, and the species featured in Vic Savery’s photos below is an easy one to identify: the long antennae and chunky body are characteristic of a bush-cricket, and the pale crescent around the edge of the side-panels of the thorax are a dead giveaway for Roesel’s Bush-cricket (Metrioptera roeselii).

 cricket  cricket 1
Roesel’s Bush-cricket, 12 August 2013, Avonmouth, Bristol, Vic Savery (naturenutz.net)

When the last national Orthoptera atlas was published back in 1997, Roesel’s Bush-cricket was largely confined to the Home Counties, with isolated outlying coastal populations in a few other areas. However, like a number of other species of bush-cricket, its populations have expanded since then, and it now occurs around Bristol. It is well-established in Wiltshire and Gloucestershire and has also spread into Gwent in the last decade. Robert Cropper’s 2011 book “The Orthoptera and allied insects of Somerset” documents surprisingly few Somerset sites: a strong population around Bridgwater possibly marks the southwestern edge of the current British range, although the range expansion is no doubt ongoing, so I’m sure that the species will reach Devon soon if it hasn’t already.

The song of Roesel’s Bush-cricket is a high-pitched buzzing, pitched at around 22 kHz. If like me, your hearing has deteriorated to the point where you can’t hear sounds which are that high-pitched, you’ll need to use an electronic detector to track one down. Vic tells me there were three or four singing at his site, on Kingweston Lane near Avonmouth. In all likelihood there are other sites elsewhere in the city too.

Advertisements

A Spoonbill at Slimbridge

A Eurasian Spoonbill (Platalea leucorodia) is present at the Wildfowl and Wetlands Trust reserve at Slimbridge currently. I visited the site yesterday afternoon, and the bird hadn’t been seen earlier in the day but just after I arrived at the Tack Piece hides, it flew in and started feeding very actively on the shallow pools just in front of me, and then rested up and started preening … cue the camera, and here is a selection of the best photos from the 150 or so that I took.

235 219

Spoonbill is a scarce bird in Britain, although because they’re large and conspicuous, inhabit the sort of wetland sites that birdwatchers visit, and tend to hang around for days, weeks or months, they can give the impression of being more common than they really are. They are on the increase here however, and you stand a reasonable chance of finding one yourself if you spend enough time birding around the Severn estuary: I added Spoonbill to my “self-found list” with one on Goldcliff Pools in Gwent in 2009; this is the second one I’ve seen at Slimbridge and I’ve also seen birds at Steart. They are much less common inland, although my very first Spoonbill was at Chew Valley Lake over 20 years ago, and there was even one a few years ago on a small lake near Swindon.

087 084

Spoonbill numbers elsewhere in Britain have been building up for a while, and double-figure flocks are now seen in most winters in Poole Harbour, with other favoured sites including the Taw/Torridge and Tamar estuaries in Devon. However, East Anglia is doing even better, as birds have now established a breeding colony on the north Norfolk coast. All of this increase is fuelled by a burgeoning population in wetlands in the Netherlands.

227 070

Although their odd appearance might suggest that they occupy an ancient branch on the bird evolutionary tree, spoonbills are really just members of the ibis family that have evolved a specialised feeding technique and the apparatus to go with it. Spatulate bills seem to evolve quite readily in waterbirds, with Shoveler ducks, and a small shorebird, the Spoon-billed Sandpiper, also having them. There are five other species of spoonbill worldwide: two in Australasia, one in Africa, the gaudy pink Roseate Spoonbill (Platalea ajaja) in the Americas, and the endangered Black-faced Spoonbill (Platalea minor) in southeast Asia.You can see some videos of Spoonbills feeding on this page on the ARKive website.