White-bellied Cuckoo-shrike finds a meal

White-bellied Cuckoo-shrike
White-bellied Cuckoo-shrike with lunch

Cuckoo-shrikes, both White-bellied and Black-faced, are occasional visitors to our garden. This one is the former, Coracina papuensis. 

Yes, it has a black face, but the real Black-faced Cuckoo-shrikes, C. novaehollandiae, have more black on their face – compare them here. And no, it is neither a cuckoo (Cuculidae) nor a shrike (Laniidae) but is in another family, Campephagidae,  with the Trillers; Wikipedia (previous link) speculates that the ‘cuckoo’ part of their common name may come from a superficial resemblance to some cuckoos.

Common names are unreliable guides to appearance, behaviour or family affiliations, particularly here in Australia where the first European settlers met hosts of strange birds and animals and applied the nearest old-world names to them.

Dove’s disappointment

ringneck pigeon in dry birdbath
Where’s my water?

We had a bit of rain a while ago but nothing but drizzle since then so our birdbath still gets a lot of use. This Spotted Dove, an early-morning visitor, looks quite put out at the low water level.

I, of course, blame the other birds, especially the Mynahs,  for splashing it all out. They, more fairly, blame me for not refilling it fast enough. Never mind – we do try, and I did top it up when I noticed the problem.

Incidentally, the bird has had a Latin name change: it is now Spilopelia chinensis rather than Streptopelia chinensis. Continue reading “Dove’s disappointment”

Identifying a spider

black spider
My unknown spider, about 10 mm long

There are lots of spiders in Australia, in case you hadn’t noticed, and lots of different species – plenty, in fact, to challenge professional taxonomists (the people who scientifically describe, classify and name species) let alone ordinary people who just come across something cute or scary and want to know what it is.

My expertise is somewhere in between those two extremes, since I picked up a reasonable knowledge of the wildlife around me as I grew up on a farm and have added to it considerably in the last ten years.

How did I add to my childhood knowledge? How does anyone with only a beginner’s knowledge add to it? Here it is my method … if something so casual deserves to be called a method.

black spider
On the lid of a plastic drum – clearly an unnatural habitat

(1) What do I already know about this particular creature?

  • What kind of animal is it? It’s an arachnid (eight legs) not an insect (six) and out of the arachnids it is pretty obviously a spider (the others are scorpions, ticks and mites, harvestmen and pseudoscorpions, none of which look much like spiders.)
  • Size: It is medium size – head and body together are about 10mm long. (That’s not clear from the photo here, but I remember roughly how big it was. Sometimes I try to put something of known size in the photo for reference, e.g. my thumb nail (15mm wide), my little finger nail (about 10mm), a house key or a coin.)
  • Habitat: I saw it running around on the ground, looking as though it was hunting, near a farm house. It then ran up a plastic drum, so it probably also hunts on tree trunks in its natural surroundings.
  • Location: It was in inland North Queensland (specifically Mingela, but NQ and the dry climate are likely to be more significant).

(2) What do I know about classifying and identifying spiders?

Resources: three really good websites (as used below) but no good reference books.

Spiders (order Araneae) are divided into two suborders, Mygalomorphs and Araneomorphs. I know immediately that this isn’t a Mygalomorph because they are just the big hairy tarantulas and funnelwebs, so my unknown spider is an Araneomorph.

Each suborder is divided into families and that may be as far as I get with an identification because there are lots more families in this suborder than in the other one. On the other hand, knowing the family may tell me most of what I wanted to know anyway, since each family has many common characteristics. For instance, if I knew that I had a Huntsman, I would soon know all this and this. And of course learning the families, 80 of them according to Volker Framenau’s authoritative Checklist (pdf), is much easier than learning all 3634 species (so far).

(3) Method

The home page of Arachne.org lists all the Araneomorph families but is not the best for quickly identifying my spider because it has neither a key (a set of yes/no questions steering the user towards the correct identification) nor a set of photos of typical family members. Ron Atkinson’s Find-a-Spider guide has the set of questions, backed up by photos, while Ed Nieuwenhuys’ Spiders of Australia has the photos, backed up by descriptions and (if you go looking), a location/web grid which is a pretty good substitute for a key.

Let’s go for his photos this time. Half a dozen of them look similar enough in proportions and coloration to be worth checking:
housewolf-prowlingfishingground-wasp-mimic


Screen shots from the index page of Spiders of Australia

The last two are very similar to each other and the most like my unknown spider. Clicking on the Spotted Ground Spider link gets me to more and bigger photos and a feeling that none of them are quite right – but look: “Storena formosa is a very common spider … a spectacularly coloured spider that resembles the Gnaphosid Supunna picta” with a link which takes me, as it turns out, to the second of my two top picks, the Wasp-mimicking Spider. And this is the one: white spots on black body, mostly-black legs with orange-brown front legs, white stripe down the middle of the head (‘cephalothorax’ if you want to be technical, but ‘head’ will do) and nothing in the description rules it out:

The wasp-mimicking spider or Supunna picta is one of the fastest spiders in Australia. While running, it waves its two forelegs above its body, mimicking the two antennas of a wasp. The front two legs have a brown tinge. Male and females are identical and their length varies between 5 and 7 mm. This species is closely related to much larger Supunna albopunctum (7 -12 mm) but this spider has two rows of white dashed spots on its abdomen. In autumn and winter the females construct a flat very white disc shaped egg-sac of 5-6 mm. The spider feeds on ground dwelling insects and spiders.

At this point I am fairly sure I have the spider’s identity, but it’s worth checking on the other main sites. Typing “Supunna picta” into the search box on Arachne.org takes me here and gives me a little more confidence (e.g. size to 8mm here matches my guess of “about 10” a bit better than Nieuwenhuys’ “5 – 7mm”). Ron Atkinson’s site offers a Species List which takes me to a photo and description which again confirm my first conclusion.

So there we are: it is a Swift Ground Spider, aka Painted Swift Spider, aka Wasp-mimicking Spider (this is why we like Latin names!) in the family Corinnidae. Corinnidae  is not one of the bigger or better-known families (it doesn’t even have a common name) and I’m not surprised that it didn’t immediately come to mind when I saw this spider. If it had, the identification process would have been somewhat quicker.

The process I have demonstrated, incidentally, is similar for birds, butterflies or any other group of animals; I just chose spiders to demonstrate it because I had a good example at hand.

Each kind of creature has its dedicated sites and its printed guide books; my regular readers will know most of those I rely on, since I continually refer to them and link to them. And if individual research fails, there is a great community of helpful experts, especially on the appropriate Flickr groups, Field Guide to Insects of Australia and Spiders of Australia – thanks again to Rob, Graeme, Kristi, Tony, Michael, Boris, Jean, Steve and everyone else who has helped me get this far!

What is a bug, anyway?

One of my motives for starting Green Path was to document all the small wildlife I was discovering by prowling around my own garden with a camera, that is (to most people) bugs. But what is a bug, anyway, in more formal terms?

orange and black bug
True bug: Horehound Bug (Hemiptera)

If we want to be technical, bugs should really be limited to insects (six legs) so spiders are out. And to be even more technical, entomologists talk about “true bugs” which are a specific family of insects, Hemiptera (the sap-suckers – aphids, shield bugs, plant-hoppers, etc). The obvious implication is that non-Hemipteran insects are not really “bugs”, although I’ve never heard anyone actually say so.

I discussed this profound issue over a beer recently and we decided that all insects except butterflies and moths are bugs. So are millipedes, mites and ticks, which are not insects. Spiders? No, not really bugs, but not insects either. Crabs? Not bugs.

All of the above, however, are invertebrates (i.e. they don’t have backbones) and in fact they are all Arthropods, defined as “invertebrate animals having an exoskeleton (external skeleton), a segmented body, and jointed appendages.”

Mayfly hanging beneath a leaf
Bug: Mayfly (Ephemoptera)

What it all boils down to, I suspect, is that a “bug” is any small arthropod we don’t have a better name for. Frankly, I don’t worry about it too much: if a critter intrigues me or if it’s beautiful, I will want to know more and take a photo.

And “critters” = “creatures” so my scope is even broader than “bugs”. Insects, spiders, crabs, lizards, birds, koalas, people, whales … all critters, all deserving respect and understanding.

wallaby
Critter: Bennett’s Wallaby

Crows, Currawongs and Choughs

This post parallels my recent Extended Honeyeater family essay and is prompted by the same holiday experiences: visiting Canberra and Victoria before Christmas I saw birds which don’t live around Townsville and wanted to fit them in to my existing knowledge.

It turns out that currawongs, magpies, crows and choughs are not all members of the same taxonomic family but are next-nearest kin, all being members of the superfamily Corvoidea comprising three families:

  • Corvidae: crows, ravens (and jays, which don’t occur in Australia)
  • Artamidae: woodswallows, butcherbirds, currawongs and Australian magpie
  • Corcoracidae: white-winged chough and apostlebird

The links in that little list will take you to the respective family pages on Birdway and clicking on them in turn shows graphically that all three families put together contain fewer species than the single Honeyeater family.

Corvidae

We have two native crows and three ravens. They are all glossy black birds of similar sizes, so they are very difficult to tell apart.

Location is one clue. Here in Townsville we have the Torresian Crow (Corvus orru) and perhaps the Australian Raven (Corvus coronoides), and if we drive West over the Dividing Range we may see the Little Crow (Corvus bennetti). In Victoria and southern NSW, however, both Little and Australian Ravens are widespread and the Forest Raven is common within its limited range, but there are no crows.

Torresian Crow (Corvus orru)
Torresian Crow, Pallarenda NQ

I’m reasonably sure that my crows here are not ravens because the Australian Raven has much more prominent throat hackles than any of our crows and they should be obvious in my close-up.

The other two corvids on Birdway’s page, the House Crow and Eurasian Magpie, are Asian birds which have been seen here but have not naturalised. This means we only have one magpie, the Australian Magpie (Cracticus tibicen) which got its common name from the Eurasian Magpie but is not closely related to it: the Aussie is closer to currawongs and butcherbirds but the foreigner is closer to crows and ravens.

Currawongs

Currawongs are the most crow-like of the Artamidae, being just as big and nearly as black. The Pied Currawong, Strepera graculina, is black with white flashes in wing, undertail and tail-tip, all more apparent in flight. It’s the species we have here and its range extends in a broad swathe all the way down the coast to Western Victoria.

Pied Currawong
Pied Currawong, Canberra Botanic Gardens
Pied Currawong
Pied Currawong, Hervey’s Range NQ, showing white plumage more clearly

The Grey Currawong (S. versicolor), whose range extends from about Sydney across to WA, and the Black Currawong, restricted to Tasmania, are quite similar to the Pied. If in doubt, look at their eyes (crows and ravens have white eyes but currawongs have yellow eyes) or listen to their voices (currawongs are more melodious than crows).

The Chough

Finally, the bird which really triggered this exploration. I was having a thoroughly enjoyable day in Canberra’s Botanic Gardens until a niggling question intruded: just what was that other black bird? Solid black (or was that a flash of white in the wings as it flew off?), smallish for a crow or currawong but big for anything else, red-eyed, sociable and active on the ground? It didn’t ruin my day, of course – a new critter is always interesting – but it was a puzzle.

White-winged Chough, Corcorax melanorhamphos
White-winged Chough, Canberra Botanic Gardens

A bit of research identified it as the White-winged (really?) Chough, Corcorax melanorhamphos.  On the ground, the finer beak and the red eyes distinguish it from crows and currawongs; in flight, currawongs have white in wings and tail, choughs have white only in the wings, and crows and ravens have no white at all.

The only other species in the Chough’s family is the Apostlebird, smaller and browner. Neither of them is common around Townsville but we’re not far from the edge of their ranges.

Torresian Crow (Corvus orru)
Crow in pursuit of a Spur-winged Plover, Pallarenda. No white at all!