Townsville’s dry season begins

Pied Imperial-pigeon in treetop
Pied Imperial-pigeon in the topmost branches of our poplar gum

Easter seems to me to mark the usual turning point between Wet and Dry seasons here in Townsville, and it has certainly seemed so this year. Cyclone Debbie was looming as we left for Bali on March 25 but by the time we returned, a week ago, humidity had dropped right off, nights were noticeably cooler, the frangipanis were losing their leaves and the prospect of more real rain seemed to have evaporated.

I would love to be proven wrong on this, because Continue reading “Townsville’s dry season begins”

Rain!

A couple of days ago I said, “We’ve been promised rain every day for a week and seen very little – ‘scattered showers and storms’ is a fairly generous description,” Then it started raining, quite steadily.

A week ago I said, “If there’s a fixed open drain, [grey water on a rural property] might run into a banana patch, since bananas are always thirsty.” Now our bananas are standing in ankle-deep water, run-off from  the higher side of our own block and from our neighbours.

People around the city are reporting falls of 30 – 120mm over the last few days as the patchy showers turned into widespread rain. Townsville’s official records only tell us what fell at the airport and are taken at 9.00 a.m. every day; the total to 9.00 this morning was 34 mm and I expect tomorrow’s reading to be much higher.

Friday, 3 pm

Harbingers of the Wet

Honeyeater
Juvenile Blue-faced Honeyeater feeding in the Poplar Gum

Birds have been visiting us in greater numbers than usual thanks to the simultaneous flowering of all our biggest trees, the poplar gum, paperbark and mango. Rainbow Lorikeets have joined our resident friarbirds and honeyeaters (the Yellow Honeyeaters are still around, by the way) taking advantage of the abundance.

In the last week or so I have heard (but not seen) both a Koel and a Torres Strait Pigeon (aka PIP) in my garden. Both are Wet season visitors and both are here earlier than usual, if only by a few weeks. Of course, our weather has not been following ‘normal’ patterns. (Nor has the weather anywhere else, and climate change is largely to blame.) So far we’ve had a warmer and wetter Dry season than usual (120mm in June-July-August, more than offsetting a dry April and May), although not wet enough to relieve our water restrictions.

Rainbow Lorikeet
Rainbow Lorikeet looking for his share

Butterflies and other insects on the Town Common

Here are some of the insects I saw on the Town Common yesterday – far more numerous than the birds I talked about in my previous post, although I have to say that wasn’t entirely a Good Thing (more on that later).

Butterflies

  • Marsh Tiger, Danaus affinis
  • Lesser Wanderer aka Plain Tiger, Danaus chrysippus
  • Common Crow, Euploea core
  • Blue Tiger, Tirumala hamata
  • Common Eggfly, Hypolimnas bolina
  • Blue Argus, Junonia orithya
  • Bush Brown, Mycalesis sp.
  • Grass Yellow, Eurema sp.
  • Clearwing Swallowtail, Cressida cressida
  • Black-spotted Flash, Hypolycaena phorbas

Of these, the first two are always abundant on the Common and the next three are nearly as common. All five are about the same size. The next three are all smaller. They are also common but are trickier to identify because close relations in each genus look so much alike (which is why I have just said “Eurema sp. [species]” and so on). The last one is the odd one out, belonging to a different family (Lycaenidae) and being much rarer.

Marsh Tiger butterfly
Marsh Tiger
Plain Tiger butterfly
Lesser Wanderer or Plain Tiger
Common Crow
Common Crow

One of my reasons for posting these three photos as a set is that they happen to show all three species feeding on the same kind of flower, the Tridax Daisy.

Black-spotted Flash
Black-spotted Flash, female

Lycaenidae (Blues) are usually quite small but this one is bigger than most, about the same size as the Grass Yellow.

I did also see many other small butterflies and moths but they were impossible to keep track of.

Dragonflies

Golden dragonfly
Golden dragonfly, unidentified
Red dragonfly
Common Glider, Tramea loewii

Standing water always means dragonflies and they were as numerous as the butterflies. Once again, I couldn’t begin to identify all of them and I’m just posting a couple who posed nicely for me.

And the rest

Add together the numbers of butterflies and dragonflies and you might be close to the total number of grasshoppers; add together the grasshoppers, butterflies and dragonflies and you might be close to the total number of mosquitoes – or that’s what it felt like! The Common is not a place to visit without repellent in the Wet season.

Most of the mozzies were the little standard-model grey-black types but one, seen below attempting to drill through my pants leg, was special enough for a photo.

Brown mosquito
Brown mosquito

She (males don’t suck blood) was about twice the average size – perhaps not as big as the magnificent Metallic Mosquito, but close.

My oddest discovery of the trip was this:

Pandanus leaf
Pandanus leaf

Pandanus leaves are spiked along the edges but this one – and others on the same plant – seemed to have pairs of supernumerary spines coming from the lower face of the leaf. A closer look revealed that each pair of ‘spines’ was a pair of wings attached to plant hoppers (Derbidae, Hemiptera), each of which was attached to the leaf via its proboscis (properly called a ‘stylet‘) and earnestly sucking sap from a vein.

sap-suckers on leaf
Derbid plant-hoppers feeding on pandanus

The Town Common after rain

lagoon
Freshwater Lagoon from the bird hide

I visited the Town Common today, for the first time in months, to see what our recent rain had done for it. The good news is that there was plenty of water; the bad news, for bird-watchers, should also be apparent from my photo.

Where are the birds? Flown, in a word – dispersed to inland areas which have also received good rain. This happens in every Wet season, of course, and the birds drift back towards the coast and permanent water as the Dry season progresses, but visiting the Common and not seeing a single magpie goose, or even an ibis, still feels weird. That’s what happened, though – magpie geese, ibis, spoonbills, egrets, cormorants, pelicans: nil.

Smaller birds were still around, however. I saw a couple of Sacred Kingfishers, one Forest Kingfisher, a Dollarbird, several Sunbirds, one White-throated Honeyeater (I think) and a small flock of young Crimson Finches.

brown finch with red tail
Juvenile Crimson Finch

These young finches will grow up to be much more colourful, as these photos (on Birdway) show.

Seeing a sunbird improves any day, so I will post one of today’s shots before I sign off. Dragonflies do, too, but I will leave the Common’s abundant invertebrates for another post.

Sunbird on twig
Yellow-bellied Sunbird, male

First Koel of the season

koel in flight
Koel in flight

Yesterday I saw my first Koel (Eudynamys orientalis ) of the season. They are wet-season visitors and this gentleman timed it well, arriving a day after the torrential downpour we copped (‘received’ is too polite a word) on Monday night.

He is, as I said, a male (females are speckled) and in my photo he is flying from our paperbark to the top of a nearby palm. He looks ragged, and in fact I found one of his feathers on the ground later, so perhaps he was caught in the same storm.

I wrote about Koels at length a couple of years ago so I will simply refer you to that post for further information rather than repeating myself.

Townsville’s record-breaking 2015 rainfall

I have been grumbling for months about how dry Townsville has been in the last year, and the annual figures are now in: 2015 was the driest year on record, with just under 400mm compared to our average of 1135mm and our highest-ever of 2400mm. We have just continued the pattern by completing a dry January, 77mm compared to an average of 270.

tsv-rainfall-low-highMy figures are from the BoM’s Climate Data Online for Townsville airport, here (I have rounded them off to the nearest whole millimetre). Looking at the annual rainfall totals in that table, a pattern pops out: four-digit and three-digit totals don’t alternate randomly but come in clusters, 3-5 of each at a time. For instance, 2001-06 were all below 1000mm, while 2007-12 were all above it. Extracting the first and last columns and colouring the totals blue for wet years and brown for dry years (see table at left; click on it for a larger version) makes the pattern more obvious, and highlights one other quirk: a run of dry years is sometimes interrupted by a single wet year (e.g. 1968 and 1981) but the converse isn’t true.

tsv-rainfall-low-mid-highI also divided the range of annual totals into three: close to average (1000 – 1300 mm), wet years (more than 1300) and dry years (less than 1000). Colouring them appropriately brings out another feature, showing just how rare an “average” year is: only one year in five is within that zone.

Monthly rainfalls also vary wildly. I could repeat the same exercise for  (e.g.) January rainfalls, where the average is 270mm but the actual figures vary from a mere 9mm to 1142. We can’t even say that a wet January is particularly likely to be followed by a wet February and March. Sequences like 85 – 549 – 53mm (2002) and 19 – 316 – 73mm (2003) are not uncommon.

In fact, we have to realise that an average month or year is not at all normal.

Climate is what we expect, weather is what we get

So can the statistics tell us anything useful at all? Well, yes. They can obviously say things like, “Yes, 2015 was much drier than usual. It wasn’t your imagination.” They can also warn us not to expect an average month or year, something that long-term residents are vaguely aware of but many newcomers are not.

More subtly, they can warn us that we are getting a run of extremes and should be concerned by them. As Hansen warned us some time ago, every broken record carries the fingerprint of climate change – not necessarily caused by climate change, but made more likely by climate change.

They can show us, too, how our climate is changing over the long term – and those trends are likely to continue into the future, over at least a similar time-frame. “Climate is what we expect, weather is what we get,” (the quote is well known but its origin is obscure) and in those terms it’s clear that we need to look at periods of more than ten years.

Fortunately, we have done that – well, the BoM has, and has made the data available to all of us online. In particular, their trend maps make long-term changes beautifully (scarily?) clear. Here, for instance are the national rainfall and average temperature trends since 1970.

rainfall-trends

temp-trends

Food for thought – especially the extreme drying trend down the East coast, where most Aussies live. For more detail, follow my link to look into different regions, seasons and data sets.

As for Townsville, all we know is that we don’t know what to expect. The BoM made some educated guesses for the Townsville Bulletin’s January 4 article about our meagre 2015 rainfall but most of the article was concerned with very short-term forecasts. The BoM’s Outlook page suggests that the North will be drier and hotter than average in the next few months, Feb-April, but we shall have to wait and see.