Although chasing rare birds is fun, it’s not practical for me these days 🙂 ! So I’ve been watching the grebes on the Decoy Lake at Shapwick Heath for a few weeks now, and I’m finding that I’m learning much more than I’d expected. I’m learning to read their behaviour – of which there has been plenty this month.
By the end of February, I reckoned I had sussed out the territories on the lake. The pair that had been there through the winter had the pick of the sites, and chose the area to the left of the hide. One of them (the male?) was notable for defending his patch whenever threatened. To the right of the hide was a more recent pair that quite often invaded the left pair’s territory, with predictable consequences. The boundary between the two seemed to be from the left hand side of the hide to the tor, given the point at which hostilities would begin and end. In the distance, towards the tor and to the left-side of the lake, was another pair which didn’t seem to interact much with the two nearer pairs, and may well have held the whole of the far end of the lake – but were too far away for me to be sure.
Then came the snow. When Jen and I visited the hide on the snowy Friday, it seemed as if there was only one pair on the lake, and given where they emerged from this was probably the pair from the right of the hide – although I was slightly puzzled as this would mean that the wintering pair, despite holding on through the winter, had left.
After the snow left the other grebes returned – though apparently not all of them. A few days later I only saw one grebe at the far end: I presumed the other was hidden in or behind the various reed beds. I confidently explained the three territories to a couple who were visiting the hide for the first time – honestly, they seemed genuinely interested! – but the knowledge I was boasting of was no longer true. After they left, I happened to see that there were two pairs on the far left side, with only a few metres separating them, simultaneously doing courtship displays. This was clearly about territory as much as romance. I wish I’d been able to photograph this but they were too distant for a good photo.
The closer of the pairs then chased the other pair off – my next surprise was that the more distant of the two didn’t retreat into the distance, as I’d expected, but across the lake and back to area just to the right of the hide. In fact, as soon as they crossed the line from the hide to the tor, the male (presumably) changed from fleeing to defending. This can be see in the photo below if you click to enlarge.
I discovered later that this was only one skirmish in a longer-running battle. By the time I returned the following week, order had been restored – but there had been a dramatic shift in territories, and I can only infer what had happened. The pair which was based to the right of the hide now seemed to have the freedom of the near half of the lake. Towards the far end of the lake, to the left, another pair was bobbing on the lake, calmly asleep.
What battles had taken place? Who had won? And which grebe was where? The simplest assumption may be that the wintering grebes, to the left of the lake, had been ousted, and they may have then settled at the back of the lake, territory that had been vacated by one of the earlier grebes not returning after the snow. I would have to interview the grebes themselves to produce a more reliable picture!
The advantage of this new arrangement, from my perspective anyway, is that the hide pair are freer to live their lives in front of the hide, without being chased off by the other pair. Take, for example, one extraordinary attempt at fishing….
How on earth the grebe thought it would swallow that size of fish beats me! – and I was hardly surprised when it dropped its potential prize.
The grebes have been amorous all month and would regularly re-unite after a long separation of, say, half an hour, with prodigious headshaking and neck-bending.
I’ve not yet seen a full weed-dance this year in clear view – but came close last week.
Only one of the pair had brought weed, so the dance ended fairly quickly.
Earlier this week I saw a territorial encounter between two of the grebes, on the far left of the lake, near where the two pairs had been displaying previously, and which confirmed my suspicions about the new territories.
It was only when I looked at the photos below carefully that I realised how far the left grebe had advanced, and how far the right grebe had had to back-paddle! I expected a full-blown fight but the left grebe dived away. He returned to his base, to the right of his hide, and a bit later he and his mate surveyed the territory where the stand-off had taken place, while the grebe that retreated remained a short way off, affecting a lack of interest. The re-configured territories are as I suspected: the hide pair now has the full width of the lake near the hide.
Much as I’m biased towards the grebes, there’s been plenty of other interesting wildlife on the lake. Earlier in the month another birder told me three whooper swans had been seen on the lake the previous evening – had I seen them? I hadn’t, and as we chatted over the next half hour, there was no sign of them. A few minutes after he left, two whooper swans swam in from the back of the lake – why they hadn’t already left for northern Europe was unclear.
However, it makes sense to end this post with a couple of grebe portraits.