Mallee Frog Blog

Our dry September is over. October started the same way but has finished with two big rainfall weeks, of about 40mm each. The first big rain was enough to bring calls from the pobblebonk and spotted marsh frogs at the pond. Curiously, no calls from the dam. Compared to other times when we've had big rainfall events, the dam has been very quiet. Only tonight, after the second big event, have I heard a spotted marsh frog calling from the dam.

The dam is very different this year. Last year it was an irregularly irrigated grassland. This year it's been a proper dam, and the greywater is growing grass in the dam next door. The shallowest the water has become is probably about 30cm, and it is about double that again now. There is abundant insect life on the water, but much less dead plant material, and shelter in and around the water. There is heaps of shelter around the dam itself though. It's difficult to understand why there seems to be so much less frog activity (as measured by calls) this year. Maybe they're all just out and about and busy.

Other things we've noticed - our sparrows have disappeared. Could it be the mouse bait? And we've had three wild ducks spend some time on the pond and dam, although I haven't seen them in the last fortnight. There are some great owl noises some nights. I'll have to sneak out one day and follow them and see if they are really owls! 2010 has been a really different year.

I haven't posted on the frogs for a while. We've had a wet winter, but it's also been quite cool, and they've been very quiet. Could also be that the ducks have discovered the frog pond every so often and they've been scared!

Tonight I stood outside and for the first time this winter heard a single spotted marsh frog call, from the pond. Listening closer, I realised I could hear a lot of frog calls, coming from the direction of Manangatang. I could make out spotted marsh frog, spadefoot toad and pobblebonk. It must be noisy in there! Weird that we aren't hearing more here. The dam has been full of water all winter, and now it's nice and clear fresh water (not the greywater). Maybe they liked the anonymity of the greywater? Actually the pond has also become quite clear. 

The greywater is currently running into the big dry dam next door, and has created a frog habitat par excellence. Lots of grass and a cascade of ponds as the greywater spills down and infiltrates. There must be some there now.

Yesterday we had a gentle 5mm, on top of 20+mm earlier in the week. There has been another decent rainfall between this and the last time I wrote (mid Feb). This seems like the wettest summer/autumn for years, although I think 2004/5 and 1999/2000 were similar.

The frogs have been loving it. The runoff dam is as full as I've seen it and will probably keep a decent depth of water throughout the winter, even if it's dry. Today I took the greywater out of that dam, and I'm going to run it into another dam and see if we can get some things happening there. I don't think the nutrients are good for the dam with water in it - it was getting some scum on it before it rained - and the vegetation at the edge (which could use the nutrients) keeps getting drowned.

The frogs have been going crazy the last couple of nights, mostly spotted marsh frog calls. This morning there were three egg masses on the pond, and at least four egg masses just on one side of the dam. There may have been more but it's a bit slippery to go walking around too much. Looking at the dam there is plenty of tadpole activity, and there have been many dragonflies too. There are also locusts around in the paddocks near the dam but none actually around it, as far as I can see. They would be good frog feed!!!

The frogs also seem to have the mosquitoes under control. It hasn't been too bad outside, but they are definitely around. Probably more with water collecting on old machinery etc. rather than the pond or dam.

The frogs have been mostly quiet since Christmas, when it started drying out. The dam has had water and has had plenty of tadpole action going on in it but not so much calling. The pond water has been quite clear. I switched the water off when it was raining and only remembered to turn it on a week or so ago when it started looking very shallow.

The increased water level didn't trigger frog calling straight away (it was relatively hot) but the remnants of a cyclone are now heading towards us together with low pressure and the frogs in the pond (all spotted marsh frogs) have become very vocal. The frogs in the dam have been quiet - perhaps because the water level has continued to fall.

About a week after the first 35mm, we had another 45mm over a couple of days. That caused some grain damage, but has created frog heaven. The dam has been as full as I've ever seen it (after rain) - at least 60cm of water with most of the winter vegetation submerged.

Frogs have been calling crazily each night since then, mostly the Pobblebonk and Spotted Marsh Frogs, although we did hear some Spadefoot calls early on. They can be heard kilometres away. A real audio beacon for other frogs. There have been few calls from the pond (maybe I just can't hear them!). I haven't had a look for a week but when I went down to the dam this morning there were at least three egg masses, all on the eastern side of the dam. The water will be thick with tadpoles soon.

For the last four weeks it's been pretty quiet on the frog front. The dam had nearly dried out (apart from the sump we dug last year to keep the tadpoles alive) and we'd had some really hot weather. It was just too hot to keep the tadpoles on the back verandah - and I wasn't keeping up with the pace of frog emergence. I was taking the frogs down to the dam because there seemed to be way more food there for frogs, and enough moisture for them to get by even if the sump dried out. In the end I decided just to dump the whole lot back into the sump a couple of weeks ago and they seem to have been fine there.

Over the last couple of days we've had 34mm of beautiful, steady rain and it's put about 30cm of muddy water in the dam. The frogs tonight are going crazy! They started today (spotted marsh frogs) and this evening we can hear all three species - spadefoot, spotted marsh frog, and pobblebonk. The pobblebonk seems to be exclusively from the dam but the other two are coming from both dam and pond. Amazing sounds.

Over the last week we've had an amazing 45mm of rain, which has put some more water into the dam and renewed calling from the frogs there. Spotted marsh frog calls mainly, but I think I hear the odd spadefoot as well.

The pond frogs have faith in the season and have spawned again - this their sixth batch of eggs for 2009. These ones (photo below) seem smaller than the others I've seen - not sure why that is. 

The tadpoles on the back verandah have been growing and the rain seemed like an ideal opportunity to release some back into the dam. I did this on Saturday afternoon (photos below). There seem to be 39 of them in the bowl that we put back in. For a little while they were stunned, perhaps because the water was a bit colder than what they came out of, but soon they started nibbling on the bottom and getting back into the swing of tadpole life. I hope that some of them survive to make froglets. They are already getting back legs and will probably enjoy the dam environment better than the glyphosate containers (despite the carefully constructed shelves for them to rest on).

There is a second generation of eggs in the pond tonight. There has been regular spotted marsh frog calls from the pond and it seems they have been busy. Somewhere underneath all the vegetation the first generation of tadpoles should all be growing too. We haven't had rain for a while but the calls have been ongoing.

The tadpoles we rescued from the dam continue to grow. We're looking forward to Jon (BCG) finishing his next survey so we can possibly release them into some other ponds - and reduce the population in glyphosate containers on the back verandah. At the moment they're being fed on frozen spinach, silver beet and broccoli leaves and seem quite happy but the water gets dirty quickly (there's lots of them). Love the flurry that happens when you disturb them eating. At night you can hear the frenzy going on!

I got such a surprise the other day. The dam has been drying out - we've been trying to kill the wrigglers. I thought there were no tadpoles in it; hadn't seen any eggs and wasn't able to see any tadpoles swimming around either.

I went out to the sump in the bottom of the dam and there were tadpoles rising up for gulps of air. We fished at least 100 of them out with buckets and a flyscreen, and put them in the glyphosate container on the back verandah. Most of them are huge! With a few smaller ones in amongst them. Judging by the size, I think they're probably Mallee Spadefoot Toad (ie. they are that big because the eggs were laid a while ago, when the Spadefoots were calling)**. There is the odd darker tadpole which I think must be Spotted Marsh Frog (lower photo).

We're going to have to rationalise the population a bit - have sent some into school, and are considering whether to introduce some to other dams and ponds around the place.

** have since found out that Mallee Spadefoot Toad tadpoles are dark/black, which rules these out. They could be Common Spadefoot Toad (Neobatrachus sudelli) perhaps?