A stroll around the Palmetum

The Palmetum is one ‘campus’ of Townsville’s botanic gardens. Its special focus is palm trees, as its name implies, but palms range across so many habitats, from rainforest to desert, that the gardens are very varied. I found lots of wildlife to photograph on a Saturday afternoon stroll, even well into the Dry season.

grey honeyeater
Little Friarbird, Philemon citreogularis.

There were plenty of birds – Rainbow Lorikeets, Ibis, Black Duck and a few other familiar species, plus one which I had to look up. My first thought that it was a honeyeater, since it was about the size of our Blue-faced Honeyeaters and had a similar patch of bare skin on its face, but it turned out to be a Little Friarbird. I hadn’t been far wrong, however, since friarbirds are members of the same family (Meliphagidae) as honeyeaters.

But insects claimed most of my attention, although numbers were down in the park just as they are at home. I found a peculiarly-equipped bug,  several species of orb-weaving spiders, damselflies around the lagoon and in the rainforest, a few dragonflies and a few butterflies.

two brown butterflies on a leaf
Getting acquainted? Two Orange Bush-brown butterflies, Mycalesis terminus.

These butterflies are seen year-round but their colours, like those of other leaf-mimics,  depend on the season. Melanitis leda, the Evening Brown, is my favourite example of how they change – look at this collection.

Pop(u)lar Gum in blossom

Our huge Poplar Gum (Eucalyptus platyphylla) has, as predicted, burst into flower – suddenly and exuberantly. The trigger seems to have been the few millimetres of gentle rain which arrived on Sunday, since by Monday the whole tree looked like this:

creamy gum blossom
Poplar gum blossom

It has become enormously popular with the Rainbow Lorikeets (Trichoglossus haematodus) in consequence. They have abandoned the paperbark (they had nearly stripped it, anyway) and dozens of them at a time are feeding in the canopy.

Rainbow Lorikeet in the Poplar Gum
Rainbow Lorikeet in the Poplar Gum
two lorikeets arguing
Two lorikeets disputing over the flowers

Anyone standing beneath the tree is showered with the caps off the flower buds, and with fragments of twigs, leaves and flowers.

The birds keep up a screeching racket which bursts out even louder when they squabble, as they often do.

With all that, they are (as I said last week) very difficult to see. They have an amazing knack of vanishing into the leaves. When you watch for a while, you can see most of the ‘why’ and ‘how’: they have to walk around on the small branches and reach out through the leaves to the flowers, because the flower stems are not strong enough to take their weight.

Lorikeet with head showing through leaves
Now you see it …

Their colours are surprisingly good camouflage, too, as the bright blue head becomes sky in sunlight and grey branch in shadow, while the green and yellow become leaves.

How much of the bird can you see in the small picture here? Click on it for a larger version and look again.


Ephemera in the Mist – Environmental Art Festival, Paluma

Ephemera in the Mist is an environmental art festival featuring installations in the rainforest of Paluma between August 25th and September 9th. I went to the inaugural festival last year and enjoyed it – see this report. This year’s event follows the same format. It has two key components:

Rainforest Organic Art Trail, a series of site-specific ephemeral installations built in the rainforest around Paluma. The artworks will be created within strict environmental guidelines and will be left in situ to gradually disintegrate back into the forest floor.

Village Sculpture Walk, a separate show in Paluma Village of enduring sculptural works with an environmental theme, created predominantly from recycled materials.

Cash prizes will be awarded for the People’s Choice in each of these two exhibitions.

Complementary activities include an exhibition of small artworks in the Community Hall; an artists’ marketplace on the village green; free art workshops with guest and local tutors; nature walks guided by a resident naturalist; artist talks; and a display of environmentally proactive products and organisations.

Official opening: August 25th
Workshops & Artists Market: August 15th & 26th. Entry is free.
Sculpture trail will be on show until Sept 9th
More information: 0418 750 854 (Sue Tilley) or http://www.ephemerainthemist.com/

Two species of Crow butterfly on the Common

Two dark butterflies on a treetrunk
Two species of Crow with not a feather between them

At least four species of Crow butterfly (Euploea) are found in the Townsville region, three in the immediate vicinity and the other at least as close as Jourama Falls to the north.

Here are two of them together: E. sylvester, the Two-brand Crow, is perched above E. core, the Common Crow. It is not too hard to tell them apart when they are seen together like this (the large white spots follow the edge of the wing in E. sylvester but cut straight across in E. core) and the third local species, E. tulliolus, (photo here) is even more distinctive. But they are all much the same size and coloration and in isolation are easily mis-identified.

I found them in a large mixed aggregation* on the edge of Townsville’s Town Common on my visit a fortnight ago. Peter Valentine tells us that this behaviour is normal in the Dry season but you have to be in the right location to see it – in this case, a patch of cool, dark, damp woodland at the foot of Bald Rock, just near the bird hide. Dozens of them, perhaps hundreds, were in constant motion, restless but never flying far. All they are doing, really, is passing the time until the Wet, their breeding season, arrives.

There were Blue Tigers, Tirumala hamata, in the same little spot but the Marsh Tigers, Danaus affinis, and Plain TigersDanaus chrysippus, preferred sunnier areas nearby.

Marsh Tiger, Danaus affinis, camouflaged in long grass
Marsh Tiger, Danaus affinis, amazingly well camouflaged in the light and shade of long grass

* Flock? Swarm? Wikipedia tells me that the correct collective nouns for butterflies are ‘flight’, which sounds okay, or ‘rabble’, which doesn’t and isn’t even dramatic like the collective noun for feathered crows, ‘murder’. None of them seem quite right.

Defining a rapidly changing climate

If the climate is changing, what is it that’s changing? Climate, they say, is what you expect, while weather is what you get. But if climate is changing, how do we know what to expect?

That may sound flippant but it has become quite a serious question in climate science circles of late, for two reasons: communicating climate science to the public, and dealing with the statistical problem of defining a moving target.

On the first question, for instance, we have a typical member of the public asking on the RealClimate open thread“One thing that has confused me is how long it takes for weather to become climate.”

One of the regulars replied: “WMO (World Meteorological Organization) states that climate is 30 or more years of weather data.” Another backed him up, saying, “The traditional answer is 30 years or thereabouts.” ‘SecularAnimist’, another regular, answered at greater length:

I think this question is increasingly irrelevant, and the “traditional” answer is becoming obsolete.

The question was relevant when we were asking whether the various atmospheric conditions, processes, events and patterns of events that comprise “climate” are in fact changing, and wanted to know over what length of time we’d need to observe those phenomena as ever-changing, short term “weather” to be able to conclude that the changes are sufficiently long-term to be considered “climate” change. But we already know that the climate is changing, and will continue to change, as a result of our CO2 emissions. We don’t need 30 more years of observations to tell us that, now.

And the “traditional” answer is obsolete because it presumes that the Earth’s climate is sufficiently stable, and changing so slowly, that it really does take 30 or more years of observations to detect any long-term, large-scale change. That’s no longer the case, because the climate system is being driven to change more rapidly and extremely than it has ever done in human history. It’s unlikely to take another 30 years for the American midwest to become desert. It’s unlikely to take another 30 years for the Arctic sea ice to disappear completely during summer — with all of the prodigious effects that implies.

There is every reason to expect that permanent, large-scale, dramatic changes, which cannot reasonably be called anything but “climate change”, may now occur on time scales of a few years, rather than a few decades, as would have been expected in the pre-AGW world.

The more technical problem with the definition of climate is that weather needs to be averaged over enough annual cycles to iron out the bumps caused by specific weather events (that’s where the ’30 years’ comes from) but if, for instance, the averages of the 1980s, 1990s, and 2000s are successively quite different from each other then a ‘climate’ defined by the 1980-2010 average becomes meaningless.

Should we just average over a shorter period, then? No, because known multi-year cycles such as El Nino will distort the result too much. As far as I know, the experts are still working out what to do about that. Meanwhile they tend to define our baseline climate by the period from 1951-1980. James Hansen, whom I have mentioned before, presents the reasons very sensibly in a very recent discussion of his recent ‘climate dice’ paper:

Studies of climate change generally use some base period to define an average climate and calculate “anomalies” relative to that average, i.e., climate anomalies are the deviations from that average climate. In our papers we used 1951-1980 as the base period.

Global temperature change over the past century (Fig. 1) helps us discuss possible effects of the choice of base period. Our choice of 1951-1980 as a base period has several merits:

1) The period 1951-1980 is prior to the large warming of the past few decades. If we wish to examine the effect of that global warming on climate, we must compare with the climate that existed prior to that warming.

2) The 1951-1980 period has the best global data coverage and can best characterize climate variability. Spatial coverage of data was poorer at earlier times.

3) 1951-1980 was the base period used by the National Weather Service and other researchers when we made our first analyses of observations and climate simulations. For comparison with these early analyses and climate simulations we should use the same base period.

4) Many of today’s adults, baby-boomers, grew up during 1951-1980, so it is recent enough for many people to remember what the climate was like.

The whole discussion is well worth reading, since it presents the key findings of the longer and more technical paper in a very approachable way. Download it (pdf) from here.