The Pond Diary 2006
March (part 2)
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16 March - What a difference a day makes - Grey skies and temperatures of no more than 4C have meant that instead of seeing (and listening to) over a hundred frogs, today there is not one at the surface at 1pm. In fact, I can see very few at all -they must have hidden themselves in the debris at the bottom.
19 March - The last few days have seen absolutely no activity in the ponds, but today, for a while, they came to life again.
I spent most of the day working at the bottom of the garden so it wasn't possible to take any photographs. Until the late afternoon the skies were cloudless and in the sunshine it looked as though spawning was getting back underway. There was lots of croaking, and I saw one major gathering in the shallow end.
However, as soon as the sun dropped behind the trees the pond went quiet again, despite the air temperature remaining around 7C at 5.30pm. I've just checked the pond again - there may be one new clump of spawn.
Tonight, there are some frogs at the surface, just 'hanging about' like this one. I can see a few pairs coupled up under water.
I spent some time by the pond around 10pm, looking for something that I have grown used to spotting at this time of year, and it wasn't long before one appeared in the weed just in front of me.
It's one of last Spring's brood of young newts, which still has external gills and will have been in the pond for the best part of a year. I wonder when metamorphosis will finally be completed for these youngsters. There is plenty of food in the pond, so that can't be the reason for their delayed development.
It's not only frogs that can be seen holding onto a partner at this time. A closer look reveals that there are pairs of isopods scurrying around the vegetation and pond bottom.
I think they are Asellus aquaticus (the Water Louse) and in the picture their heads are towards the bottom of the picture.
21 March - Another cold, dull, and dry day with my frog activity either in the day, or this evening after dark.
In contrast, while there was no sign of them during the day, the newts became very active as soon as dusk had passed, and I could see 20-30 of them at around 7.30pm. I haven seen any newtlets today.
These are probably groups of Vorticella, solitary individuals that sometimes gather in dense groups. When disturbed, their stalks contract and the group's overall size suddenly gets smaller.
I may try to take a closer look at these in the next day or so.
Perhaps they have given up on spawning for this year?
On a positive note, I spotted the first Pond Skater of the year this afternoon.
After the cold start to the year, now we need some decent weather to get the pond plants growing to provide the leaves that the newts will need for egg-laying as we head towards the end of the month. Last year, I first saw this happening on 25 March.
As usual, I cleared quite a bit of 'weed' from the pond during the Winter, but unlike last year the remaining plants are not yet showing much sign of growth up to now.
Tonight, the frogs remain submerged, even though the water temperature is 6C and the air temperature over 7C at 9pm. In one corner there must be at least a dozen in a 'pile' on the pond bottom. The newts are very active and I think I saw a male displaying.
A few days ago I photographed a newtlet. Tonight I had another chance when I spotted two, apparently hunting in the same patch of weed.
The upper image shows the pair, the one on the left measuring about 3cm in length and the right-hand one 3.5cm - that one is shown in close-up in the lower image.
24 March - Overnight rain and mild temperatures brought the frog population up from the depths, filling the garden with the noise of their croaking as they renewed their efforts to find partners for spawning.
The rain had ensured that much of the original spawn was submerged and today the frogs were all over it.
Although this picture shows just three frogs, there must have been close to the numbers we were seeing back on the 15th.
Despite all the activity, by the end of the day I could only see two new clumps of spawn.
It seemed that there was a lack of females ready for spawning, although there were males hanging on firmly to prospective partners.
25 March - just a brief update - After a bright start the day turned dull, and it's raining this afternoon. Nevertheless, the outside temperature is still 12C at 3.30pm. The frogs continue to be active in, and around the ponds.
Last night it was also raining when I went down to my shed at 10pm. I couldn't rush to get there because I had to pick my way between the frogs on the path!
26 March - A mild night, with temperatures only dipping to just below 10C mean continued frog activity, although it isn't at the level that we saw two days ago. It's a dull morning, with heavy rain forecast for later today. When that arrives I would expect to see the frogs start turning away from spawning to thoughts of food, and venture away from the ponds.
The newts continue to hunt, and last night I saw several amongst the spawn, even with the frogs still active there. The spawn seemed to cushion the blows when frogs blundered into them or trod on them.
With the urge to mate declining, the frogs seem more and more content to the spawn as a place to rest, with many sprawled across it, showing little interest in others moving nearby.
27 March - On a wet and very blustery morning, both the air and water temperatures are around 11C, but there is hardly a frog to be seen, just a couple of snouts disappearing under the water when I walked past the pond at 11am. It looks as though spawning is finally over for the frogs. Neither am I seeing any around the garden, so they haven't switched to hunting mode yet.
As you will see in the pictures that follow, much of the spawn is developing well. However, there are several clumps of infertile spawn, showing up as the egg mass turns white.
The spawn now ranges from fresh to embryos near to release from the jelly, and it is the centre of attraction for the predators.
Here, a male,
and here a female search amongst the spawn.
Even this newtlet gets in on the act.
The newts don't just stalk around the spawn clumps. You can tell where there is one as the spawn 'wobbles'. Look carefully and you can see a bit of the back of one that is burrowing through the egg mass.
It's not just the newts that show an interest in the spawn. I could see (but didn't photograph) several large white flatworms, and a couple of Water Scorpions.
If you look carefully you can see the end of its breathing tube breaking the water surface.
With such a spread of developmental stages, the banquet will go on for same time. I just hope that it doesn't have too great an impact on the tadpole population.
Click on images to see larger versions