Spines, sockets and a sculptured mystery...

We're off to the beach today - not literally, but it is time to go back to a wet and windy visit to Cley Marshes (Norfolk, England) on Dec 4th 2009. Why? Well, when I was there, I picked up some sea urchins which were neatly cleaned out and had been washed up on the beach following rough weather. They've been on my curio shelf ever since, and earlier today I decided to have a closer look in order to (a) identify the species, and (b) look at the structure in more detail. What I didn't expect was (c) - investigate a mystery item...

So, starting at the start, the ID was straightforward enough. The specimens were all 25-40mm in diameter, somewhat flattened on top and greenish with spines (of those still bearing spines) fairly short, mostly of about the same length, and green with purplish tips. This, along with investigation of the plates and pores, makes them specimens of Psammechinus miliaris, a common species around the coasts of Britain (Hayward & Ryland, 2000).

40mm specimen with spines

25mm specimen without spines

Looking more closely, the structures become more and more fascinating. Firstly, the spines - these look like simple structures, but a closer view reveals a world of detail. The spines themselves are grooved and at the base, fit into pores like a ball-and-socket joint in a human skeleton - there are even traces of the muscle fibres attaching them and allowing the joint to be flexible, and the microstructure of the urchin's plates can be seen in the foreground..

Basal joint/attachment of spines.

Greek columns? No, a garden of spines

There are other structures too. The basal joint has pale 'drumsticks' or cotton-buds' littered about and these are numerous all over the specimen. As far as I can tell, these are the remains of 'pedicellariae' - small articulated structures (they are often toxic) which can be used to defend against predators (such as sea stars) and may have other functions (some bear tiny 'jaws' with three 'teeth'). The spines even move aside to allow poisonous pedicelliarae easier access to the threatening predator - small attackers may be paralysed and larger ones driven away. There are also some small secondary spines, but these don't have the differentiated tip shapes.

Looking at the top, the periproct (anal area) and surrounding plates can clearly be seen. There is a large plate (the 'madreporite') with numerous small pores and one larger gonopore, plus four other genital plates, each also with a gonopore - as the names suggest these are involved in reproduction.

The periproct, surrounded by four genital plates and the larger madreporite (upper right).

Now, back to the spines, and towards the mystery... Looking at the spinal bases and surface structures, I kept noticing tiny (around 0.5mm) roughly oval objects attached to the spines, mostly pink, a few more-or-less colourless. With all the other small structures and debris, I initially didn't think much of them until I realised that they were at different points on the spines (and so probably separate from them and not, for example, bits of broken-off spine tip), and then a bit of lucky lighting showed up what looked like a suture or coarse sculpturing. So, are they some other part of the urchin, or something entirely separate?

Above and below, mysterious pink ovals

 

Though tiny, they look almost like little shells, but for now, they are known as UPOs (unidentified pink objects). So, dissecting pin in hand, I managed to extract one (it was quite well attached) and put it under the microscope. This is what I saw...

Top image x40, middle pair x100, bottom image x400

First of all, I must admit I had no real idea what the UPO might be. It looks like a tiny bivalve or maybe brachiopod, but I've no clue about the size or form of, say, early post-larval bivalves, even of common species. It appears to have an attachment structure and threads at what I'm currently calling the 'hinge' or 'base'. A join/suture separates two 'valves'; this is straight basally, and sinuous apically. There is coarse surface sculpturing, although this is fine on the paired bulbous structures.

*** UPDATE - MYSTERY SOLVED ***

I posted images on iSpot and sent some to the Marine Biological Association (MBA), in the hope of more information appearing soon - and iSpot did its job after just a day. I had wondered if it was something unusual, or something very familar to marine invertebrate specialists, but otherwise not so widely known about. It was even suggested that it might be a seed blown onto the stranded urchin as there are plant seeds with sculpturing not unlike this. However, an iSpot user came up with a much more straightforward suggestion which turns out to be correct - it's the tip (or 'business end') of a pedicellaria, and so part of the urchin after all. I had been completely thrown by the unfamiliar structure without a stalk, but of course in hindsight it's obvious - the stalks seen all over the surface have in many cases got flat ends because the tips have become detached. There are few good images around showing this structure, but once I knew what I was looking for, I came across this site (the only one so far) with excellent photos, including the whole structure - the text is in Japanese, but the images do their job.

So, after all this detective work, I remain fascinated - I generally work on terrestrial and freshwater species and had no idea that these structures existed (it might have been mentioned in Zoology 101 way back, but that was a while ago...) - small mobile jaws and poison darts: wonderful! It still makes sense for a small organism to hide among urchin spines - fossil brachiopods have even been found on fossil urchins in the US (Schneider 2003). This is the sort of location where it is quite possible no-one ever looks, so even something common may well be under-recorded and such places (like the holdfasts of seaweeds) remain a potential source of interesting finds. It's also a reminder to assume nothing!

References

Hayward, P.J. & Ryland, J.S. (eds.) (2000). Handbook of the Marine Fauna of North-West Europe. OUP, Oxford. [a great book if you can get it].

Schneider, C.L. (2003). Hitchhiking on Pennsylvanian Echinoids: Epibionts on Archaeocidaris. Palaios 18(4-5): 435-444.

Woodpile wanderers and cohort-splitting

The value of dead wood as a habitat for invertebrates is well known (one of my 'static pages' covers this), so yesterday, while rummaging through our garden woodpile, I found what looked initially like a centipede about 20mm long, I felt compelled to put fingers to keyboard...

The first thing that leapt out was that it wasn't a centipede - it had two pairs of legs per segment (rather than one) and was therefore a millipede. The dorsal plates are splayed out sideways (the shape helps it push through the soil) and are coarsely sculptured along the back, and the legs and antennae are longer than in many other millipedes. Side on, it's clear why it's called 'flat-backed'.

Flat-backed Millipede

Side view showing the flat back

It's a common species, and is indeed known as the Common Flat-Backed Millipede (Polydesmus angustus). Found on roots and fruits (especially strawberries), it's often associated with all sorts of decaying plant material; dead leaves, compost, dead wood and so on. It's a native of north-west Europe, but has also been accidentally introduced to the south-east USA.

Although a common species, it does have some interesting life-cycle characteristics. Mating occurs from late spring into summer, then again from late summer to mid-autumn. Males usually mate only once, but females store the sperm from a single mating to produce several batches of eggs. Research by David (2009) showed that females born between May and August have a one-year life cycle while those born from late August onwards have a two-year life cycle (a strategy known as 'cohort-splitting', hence the title). A third type of life cycle ('interseasonal iteroparity' where iteroparity simply means reproducing more than once in their lifetime) was seen in a few females born late in the season.

Results from looking at the reproduction of individual females indicated that only annual females produced an appreciable proportion of biennial offspring from late August onwards; this means that life-cycle duration can't be genetically determined - cohort-splitting must therefore be driven non-genetically, supporting previous research by David et al. (2003) showing the effect of photoperiod (day length) on the life cycle of this species. As individual females reproduce for about two months, this automatically leads to a cyclical pattern of life-cycle duration (annual/biennial/annual) in the long-term progeny of any female.

Personally I find this fascinating, not least as an example of how a common species in an everyday habitat can surprise us with unuusal aspects of its biology or ecology. Wonderful! 

The telson and other posterior segments AKA 'the end'

Reference

David, J.-F. (2009). Female reproductive patterns in the millipede Polydesmus angustus (Diplopoda: Polydesmidae) and their significance for cohort-splitting. European Journal of Entomology 106(2): 211–216.

David, J.F., Geoffroy, J.J. & M. L. Célérier, M.L. (2003). First evidence for photoperiodic regulations of the life cycle in a millipede species, Polydesmus angustus (Diplopoda: Polydesmidae). Journal of Zoology (London) 260: 111–116.

Entomology of Star Wars. Episode II: Metallic snails and vent mussels

As Episode I proved so popular, I've been thinking about extending the 'Entomology of Star Wars' into an occasional series - not easy as I don't go in for a lot of 'speculative biology', but I'm up for a challenge and do have a penchant for Science Fiction. So, time for a bit of a nerd-fest...

One beast that I have wondered about is the big asteroid-dwelling worm that the Millenium Falcon encounters in 'The Empire Strikes Back' - what it's made of, what it lives on, how it survives in space and so on. A little online digging soon told me that it's called a 'space slug' or 'exogorth' and that it's a silicon-based gastropod (I'm pleading poetic license and sticking with 'entomology' rather than 'conchology' though), feeding mainly by metabolising asteroid minerals through its root-like tail and absorbing stellar energy, though not averse to eating the occasional spacecraft or other unwary space-dwelling creatures. Also, it apparently reproduces by fission, moulting as it grows, then simply splitting in two when large enough.

The exogorth - in space, no-one can hear you roar!

Now, I don't intend to get into the whole hypothetical silicon-based life/alternative biochemistry thing - there are plenty of people doing that already, and there's even a Wikipedia page about it here. Instead I'd like to see if there are any parallels between this fictional beastie and real-world organisms.

Firstly, the metabolising of rocks and their constituent minerals. It's well known that some bacteria (lithoautotrophs) can metabolise a variety of minerals such as sulphur, iron and manganese and are involved in both the creation of limestone cave systems (speleogenesis), and the phenomenon of acid mine drainage (AMD), the outflow of acidic water from metal and coal mines. The biochemistry of such acidophilic bacteria can be complex, but in the case of cave systems such as Carlsbad and Lechuguilla in the US, rocks have been attacked microbially in three ways:

• Oil-metabolisers - their biochemistry produces hydrogen sulphide which in turn produces sulphuric acid.
• Rock-eating bacteria - the lithoautotrophs directly metabolising minerals.
• 'Snotites' - large bacterial colonies which are primary producers in such ecosystems and drip sulphuric acid.

So, maybe the exogorth has lithoautotrophic gut flora - it has a mouth and dentition, so a gut seems likely. Thinking of a worm-like creature with symbiotic bactera does lead neatly onto the annelid tube worms such as Riftia associated with hydrothermal vents. These have become familiar creatures over the last decade or so through various TV programmes, and although they do not have a mouth or gut, they do contain symbiotic bacteria. These live within a specialised organ (the trophosome) in the worm and metabolise compounds such as carbon dioxide and hydrogen sulphide which are absorbed by the worm's plume. In turn they provide carbon compounds which nourish the worms. Similarly - and providing a handy molluscan parallel with the exogorth - vent mussels (Bathymodiolus thermophilus) are almost entirely dependent on symbiotic bacteria in their gills. Not only that, but in 2001, the Scaly-foot Gastropod (Crysomallon squamiferum) was discovered associated with hydrothermal vents in the Indian Ocean. What is unusual about this species is that its foot is armoured with 'scales' (technically 'sclerites') of iron sulphides (greigite and pyrite) and that its shell has a third layer also containing iron sulphide - it is the only animal known to use this mineral skeletally in this way. This means we do have molluscs with mineral-metabolising symbiotic bacteria, and that at least one can incorporate what we consider 'unusual' compounds into its anatomy. But, what about reproduction?

A heap of chemosynthetic vent mussels.

This seems fairly straighforward - all molluscs reproduce sexually (most gastropods are hermaphroditic), so definitely no fission. Still, although asexual reproduction is rare in higher animals, they are not unknown. For example, in Mexico, there are Topminnows of the genus Poeciliopsis where it is seen. Two species, P. monacha and P. lucida, reproduce sexually with their own species members when separate, but where they co-exist, they hybridise to produce all-female forms that reproduce by cloning (hybridogenesis and gynogenesis). In hybridogenesis, the female mates with a male, producing female offspring with both the maternal and paternal genomes. When that female produces eggs, the male genome is discarded, leading to the all-female form. In gynogenesis, females are triploid and also mate with males, but the male genome does not contribute to the offspring. There's also a good diagram explaining the process of hybridogenesis in water frogs here and there's plenty of research into gynogenesis in the African Clawed Frog (Xenopus laevis) - certainly, amphibians do seem to have a flexible approach to reproduction...

So, parallels between exogorths and real-world organisms? For molluscs, nutritionally yes but reproductively no - but what about the whole 'surviving in a vacuum' issue? Well, I think I'll leave that for Episode III...

Cretaceous Crato creature!

Last year, I was mooching around some fossil sites online and found some insects for sale. They were from an old collection and had originally been collected from the Crato Formation in Brazil. Many interesting specimens had already been sold, but among those remaining was a rather nice little beetle (according to the seller) around 12.5mm long excluding appendages. Such items are popular with collectors (including plenty with more money than me), but this one had been broken in half and neatly glued. So, still complete, but less popular with collectors and hence more affordable. Result! I bought it...

Here it is - my Cretaceous insect complete with crack, but otherwise in good condition.

...and so, it has sat in my curio cabinet for a while, until today I decided to find out more about it. First of all, the location. The Crato Formation is of Early Cretaceous age and is found in the Araripe Basin of NE Brazil. It is an important Lagerstätte (an undisturbed fossil accumulation, and today's first new word) which has yielded many important fossils - the decay conditions (or taphonomy - new word no.2) are unusual and mean that limestone accretions formed nodules around dead organisms, preserving more soft parts than is usually the case; there have even been Odonata specimens with preserved iridescence, and fish with their stomach contents preserved! The strata were mostly laid down mostly during the early Albian Age (approx 108 mya) in what was then a shallow inland sea. Crato has long been considered part of the Santana Formation (also important for palaeontology), but this is about 10 my younger and the two have now been formally separated.

Sadly, local mining activity damages the sites and a significant trade in illegally collected fossils has developed over the last decade or so. As such specimens are likely to be lost to science (not to mention incidental damage to the site), paleontologists are quite rightly calling for an urgent preservation programme - I'm glad that my specimen was legitimately collected and studied well before this became a problem; a reminder to check the provenance of anything like this, particularly for non-specialists like me who might otherwise not be aware of problems with particular sites, however well known to specialists.

So, I know it's a bit more than 100 my old, and it might be a beetle - what next? Well, as I've mentioned before, I'm no palaeontologist, but it's time to take a closer look...

The front half.

The two circular structures in the middle of this picture almost look like they could be eyes, but they are behind the sinuate line that I think must be the rear of the head or front of the pronotum. These, along with the yellowish 'figure-8' behind them, and the white subtriangular 'shield' behind that, appear to be the underlying attachments and musculature below the pronotum - possibly attachments between the prothorax and pronotum, and/or the attachment points of the elytra. The eyes appear quite bulbous and between them is a blunt protrusion - the mandibles or other appendages?

The thorax and abdomen.

Moving further back, there is a central division (about in line with the crack) and this looks very much like the rear of the pronotum. Behind this is a white area in the centre of the abdomen, surrounded by darker oblique abdominal segments; nothig too surprising there. The legs appear fairly simple and are all present - in front of the head is what might be a thickened front left femur, but I can't tell for sure - certainly the other femur looks somewhat thickened where it joins the tibia. Now, time to zoom in a bit more...

The tip of the front left leg.

The legs don't appear to have any major adaptations or obvious spines, and going by the above picture, terminate in a single straight to slightly curved claw. Moving onto the head, there seems at first to be few features, but closer examination provides a little more, at least tentatively:

Close-up of mouthparts.

Close-up of left eye (the circle is approx 0.3-0.5mm across).

 

An even closer look at the left eye.

The blunt protrusion at the front of the head does appear to be the mandibles, and they appear fairly simple (there's just a hint of a serrated join between the two halves, or is that wishful thinking aided by the handy placement of crystals of rock?); in any case there's little more to be seen here. However, zooming in on the left eye (the better preserved of the two), does reveal some interesting detail. Within the blue circle above is an area that, down the microscope, is not only shiny, but also has a few surviving ommatidia (lenses of the compound eye). At this point, my camera can do no better, but I hope that you can see some of these (six or so, faintly at the centre of the blue circle). They appear to be separated (unlike a mosaic arrangement), and thisis seen in some modern beetles (as well as the trilobite fossil that's also in my cabinet). Now moving rearwards again...

Close-up of part of the pronotum/thorax.

Close-up of abdominal segments.

 The pronotum shows layers of tissue in close-up; both what looks (to me) like chitinous material, and a small amount of what I think is soft tissue - the small folded purplish area just below the centre. The abdomen shows a similar mixture of textures, and I have to wonder whether the faint striation in the centre is the remains of muscle fibres, some other structure, or an artefact of preservation. Any thoughts on this are most welcome.

Close-up of the tip of the abdomen.

 Lastly, looking at the tip of the abdomen, what appears to be the pygidium (rear-most segment) is visible. This looks like a pair of curved 'pincers' but I expect is simply an artefact of preservation i.e. a gap left when the fossil formed. Still, some insects do have structures like this, so it could be something genuine - again, ideas are gratefully received and it would be great to be able to identify some reproductive apparatus...

So, after all that, what do I think I've got? Well, going by the general shape and simple legs, I thought it was probably a water beetle - something like the family Noteridae ('burrowing water beetles') which is already known from Crato/Santana. This example shows some similar features - leg form, overall shape, the round pronotal attachments behind the head. However, a message from Beetles In The Bush (see below) provided a quite different hypothesis. The eyes are where I think they are (the ommatidia are a good clue!), and the femurs are enlarged, and likely to be raptorial. The 'mandibles' appear to be the clypeus (so, the 'serrated join' mentioned above is an artefact/wishful thinking after all), and the revised ID is that it's a belostomatid hemipteran - a group still around and known at the 'giant water bugs' (which I've seen plenty of on my travels), although this one is less giant than many. The body shape is right, and having looked at some other images of fossil belostomatids (like this), the oblique abdominal segments are closer than seen in water beetles. Like the Noteridae, they've been found at Crato before and have one of the best fossil records of any insect group (presumably because of their large size and relatively frequent/rapid burial in shallow waters). So, I have a new (and better) ID, but I'm open to suggestions and further hypotheses. It's not the beetle I thought I'd bought, but it's still excellent and I remain fascinated by it - I'd love to learn more; I do have an 'Atlas of Macroinvertebrate Fossils', but it's only got two insects in it which are nothing like this.

Lastly lastly - for a brief extract from the 'insect' chapter of 'The Crato Fossil Beds of Brazil' (Martill, Bechly & Loveridge, 2007, Cambridge University Press), look here. For more about the whole book (it's not cheap though, RRP £92), look here (Amazon has a 'look inside' link for this title too). Soooo tempting...

A one-off or a sign of spring?

Moving on from a rarity new to Britain (see previous post), yesterday saw a specimen of the Double-striped Pug (Gymnoscelis rufifasciata) on the ceiling in my house. It's a common species in all sorts of habitats - gardens, parks, woodlands, hedges, moors - and one of the earliest to emerge, but not usually until March. It's not a fussy eater either - the flowers of holly, ivy, gorse, broom, clematis, ragwort, heather and many others are all on its menu. The caterpillars are about 15mm long, mainly brown with a yellow-brown band along the back, within which is a line of brown 'arrow-head' markings.

Double-striped Pug, wingspan 17-18mm

So, it may not be the most exciting-looking beast, but it does make me wonder if this year's long cold winter is coming to an end - winter can be a quiet time for bug-nerds! It's only one specimen, but there's a tree in blossom down the road, and a few other glimmerings in bird behaviour and so on... maybe spring has just about sprung despite this week's night-time frosts?

Of course, other one-offs don't herald a change of season. The beetle below was simply disturbed while digging over soil pre-planting a the local community farm (Highbridge). It doesn't usually appear until about June, and was distinctly keen to burrow back into the soil. It's Harpalus rufipes - note the orange appendages, golden pubescence on the elytra, and pronotum with slightly acute hind angles, curving just in front, then rounded to the sides. Common, but quite an engaging little beast - and at about 15mm long, of reasonable size for a beetle in this part of the world!

Harpalus rufipes, posing on my paw.

Reference

If you are interested in British ground beetles, the following is splendid (and you can find an errata list on the web):

Luff, M.L. (2007). The Carabidae (ground beetles) of Britain and Ireland (2nd ed.). Handbooks for the Identification of British Insects 4(2): 1-248. Pub'd by the Royal Entomological Society.
ISBN 9780901546869

What's in the box? no.3 - a new species!

OK, a little different this time - instead of a beetle arriving by post, this one was handed to me in person during the 8th Coleopterists' Day which took place yesterday at the HQ of the British Entomological & Natural History Society (BENHS) at Dinton Pastures Country Park in Berkshire, southern England.

Another thing was I knew it was going to be tricky before I even saw it - the person handing it over is an experienced coleopterist who knows his beetles, so if he can't ID it... Anyhow, being at the BENHS did mean that I had access to books and microscopes there and then, plus some other coleopterists to ask. So, starting at the start, it was about 5mm long, with blue-black elytra and head, an uptilted tip to the scutellum, orange-red pronotum, orange legs (apart from a small dark bit near the base) and dark (with an orange part near the base), fairly short antennae with triangular segments giving a somewhat serrated appearance. OK, that looks like, and keys out as, Smaragdina affinis - one of the leaf beetles (Chrysomelidae) and a rare one considered Endangered (RDB1) in Britain.

The mystery Smaragdina...

It was found on a sun-baked hillside in southern England while beating hazel (Corylus) back in June. All fine so far, except that despite the keying out, it doesn't look right for S. affinis - the main reason is the lack of a dark longitudinal stripe on the pronotum which, as far as I am aware is always present in this species. There were four other specimens in the BENHS collection (being collected in the early 20th century they were under the old generic name, Gynandrophthalma) and they all matched each other but varied from my specimen. Hmmm... it definitely looks like Smaragdina, but this genus only has one known species in Britain; could this be something really very interesting? So, having brought it home, it was time to have another look in the next morning.

There are other Smaragdina species in Europe - could one have found its way here, or been overlooked? Looking through the European species online and in books, I came to two possibilities - found not too far away in Europe, and broadly the right colour etc.- S. flavicollis and S. salicina. Looking at how to separate them, they are very similar - although varying in average length, the size ranges overlap and this specimen sits right in the middle of the overlap, so that's no guide. Also, both can have a hairless vertex to the head with a shallow round dent (which this does). So, off to the dissecting microscope.

Head on - a tricky little beast.

Head showing round depression on the vertex between the eyes.

Fortunately it's a male, so I could dissect out the aedeagus and compare it to those of the two possible species I'd come up with.

Aedeagus showing somewhat spatulate end, blunt 'pimple' at the tip, and other structures.

It's still a bit tricky (the two species are not massively different even at this level of detail), but the aedeagus does look like that of S. salicina; this species also has the antennal colouration mentioned above while S. flavicollis has more orange antennae on the whole. S. salicina is known from a range of trees, shrubs and other plants, so being found on or near hazel is fine for this species.

So, do I have a species new to Britain? Well, it's not on the most recent British list and I don't know of any publications reporting it having been found here - still, finds like this need checking to make sure.

* UPDATE * My ID has been verified by an expert - it is S. salicina which is widespread in continental Europe, including France, so it is plausible that this is a genuine new species to Britain, either overlooked or recently arrived. Next step - try to work out whether it's established/breeding (and can go on the British list) or whether it is a one-off 'import'. More info when I know!

* UPDATE 2 * This has now been published as a paper:
Hubble, D. & Murray, D. (2011). First British record of Smaragdina salicina (Scopoli, 1763) (Chrysomelidae). The Coleopterist 20(1): 1-3.

Red-breasted Goose in Hampshire: twice in one day

Yesterday, I took a trip to the area around Hook-with-Warsash Nature Reserve in Hampshire (southern England). This was mainly because, on a sunny day between bands of cloud and rain, I fancied a day out nature-watching - however I was also drawn by the reported presence of a Red-breasted Goose (Branta ruficollis), a rarity in Britain and not a species I'd seen before...

It's a sub-Arctic breeder (the Taymyr, Gydan and Yamal pennisulas of northern Russia), and usually migrates to eastern Europe (especially Bulgaria, also Romania and Ukraine, including the Black Sea coast), well away from here. However, occasional individuals do follow Brent Geese (Branta bernicla) - which breed in similar areas such as the Taymyr - further west and appear as rare vagrants. Interestingly, as they have no direct defense against predators such as the Arctic Fox (Alopex lagopus or Vulpes lagopus), Red-breasted Geese nest near birds of prey, especially Peregrine Falcons (Falco peregrinus). This means that the birds of prey protect the geese, while the geese can alert the birds of prey (who also suffer fox-predation of nests) to the presence of foxes. However, with land-use changes in eastern Europe affecting their few wintering sites and the ongoing effects of climate change on Arctic and sub-Arctic species and habitats, the Red-Breasted Goose, with a population estimated at somewhere around 38,500 globally are now classified as Endangered on the 2007 IUCN Red List.

So, there's a rare British vagrant species, endangered globally, just along the coast. What else could I do but have a look? It would be rude not to... The next decision was where to look. The area where it was reported covers a few miles of coast, as well as plenty of potential feeding fields slightly inland. A strategy was needed. Handily, two winters ago, me and a colleague did a goose and wader survey in exactly this area and so have a pretty good idea of where geese go at high tide, especially the Brent Geese which our target bird would most likely be with. So, we met up and headed for Chilling Cliffs just by the Solent Breezes caravan park. It's not where most reports were from, but it was a place we knew wildfowl used... and as we arrived there was a small group of 11 geese just offshore; 10 Brents and our Red-breasted Goose - result! Sometimes you just get lucky (helped with a little local knowledge) - a and although it's usually younger birds that get lost and migrate the wrong way, this one did have a full red cheek/head patch (some young birds do).

Result! Red-breasted Goose near Chilling Cliffs.

Our timing was lucky though as, about 5 minutes later, the small flock flew off - and we couldn't help but notice how similar the two species are in flight, once the patterns can't be seen - the same size, shape and movement, effectively the same 'jizz'. Still, we'd spent a whole winter tracking and recording goose movements in that area... so, via a brief (and unsuccessful) side-trip to see a Firecrest (Regulus ignicapillus) also reported locally, we headed to Hook-with-Warsash with its mix of coastal habitats, saltmarshes and fields. We started off looking at some arable fields where the winter wheat is popular with grazing geese. Nothing there. We then tried the saltmarshes - plenty of interesting species with about 12 species of waders using the high-tide roosts (including a close view of a 100-strong roost of Golden Plover, Pluvialis apricaria) - and headed along the coast until, about 3 hours after our initial sighting, we looked into a grassy field and there they were; about 150 Brents plus our vagrant Red-breast. never having seen one before, it was interesting to see that the books are right - despite the colourful pattern, it tended to blend in with the Brents and could be difficult to pick out, especially if seen from the rear when just a few stripes differentiate it.

A Brent Goose for comparison

Part of the Golden Plover roost

And so, a very successful bird-watching day, and a clear indication of the value of local knowledge - you can't guarantee wildlife, but you can improve your luck a bit. If you're out looking for this bird, the sites are (1) Chilling Cliffs - follow the path from the car park on the hairpin bend on Chilling Lane, and (2) Hook-with-Warsash - the field running parallel to, and on the seaward side of, Hook Park Lane near Cowes Lane. The map here should help.

Lastly, if you are interested in the topics of wildfowl and bird migration, you might like the following which should be quite affordable in paperback (both from the Collins 'New Naturalist' series):

• Cabot, D. (2009). Wildfowl.
• Newton, I. (2010). Bird Migration.

Enjoy!