Friday, 21 March 2014

International research

An interesting and exciting day.

I joined Thomas Heinicke at 0750 at yesterday’s field and the whole flock was present. Thomas had seen them at dawn on the river and then drove to the field just before the birds and saw them flying in small groups counting 149 in total (versus my 151 yesterday with the difference most likely counting errors rather than changes in number).

The 2 White-fronts and 3 Pink feet were also present and Thomas read all the same collars I read yesterday bar one. At 0850 they headed north in a few groups and we then headed for the peat bog at Flakstadmåsan where we observed a minimum of 50 Bean, 2 White fronts and 1 Pink foot with some of the same collars being read. The birds are amongst small pine trees and we kept our distance to avoid disturbing them. I have no doubt that the whole flock was here but just not visible. Some birds were initially a bit wary by our presence and stood erect but most birds and eventually these were either drinking or sleeping. It seems that this site is visited 1-2 times each day for water (the birds also sleep on the fields so this cannot be the prime reason to visit the bog).

I then received an exciting email from Larry Griffin in the WWT that the other GPS tagged bird, 06 had left Denmark and if it continued at the same speed that the initial plots had recorded then it would soon be arriving with us!!! We made haste at 1030 to the river which seemed the natural arrival point although by car it is a much longer route than the goose flies plus I had to stop for petrol. At 1102 whilst still driving I saw geese circling and flying down to the river. Could we really have arrived to see 06 and companions (we are still missing 80 birds that wintered in Scotland) arriving from Denmark? Coming down to the river a group of ca.80 Beans were on the now exposed sand bank but soon flew off, they were joined by ca.50 that had been on the far bank and left 6 still on the far bank. This was a lot of birds and they flew around calling. We could see that there were 2 White fronts with them and suspected that these were indeed the birds from Flakstadmåsan that had relocated the 15km faster than us!
We saw some birds fly towards the “old” fields at Horgen and here had 49 Bean, 2 White-fronts and a Pink-foot. 5 of the birds had inscribed neck collars showing them to be birds we had read earlier and two wore GPS/radio collars. We normally can’t identify these birds but now they were in short enough stubble that we could see their colour leg rings: one was red ring left leg, and the other white ring right leg. So now out of this flock of ca.150 birds I have read 11 inscribed neck collars, identified 2 GPS/radio collared birds and noted another 3 with GPS/radio collars. This flock has a high ratio of marked birds!!

Whilst watching these birds we received another email from Larry showing that Tag 06 was 100km due east of us near Torsby in Sweden. It had flown further north and had turned but it was not clear whether it was still flying or on the ground. It will be very interesting to see where he ends up and to find out how many other birds he is with. The wind today whilst not being as strong as yesterday was from the west which may have pushed 06 off his intended course?

Leaving Horgen at 1310 I revisited the first field and at 1330 had 20 birds here including two previously read neck collars. Straight away though a hunting Goshawk scared them up and they headed north. We had two other overflying Goshawks during the day which didn’t put the geese up but one which was hunting Wood Pigeons at Horgen did cause the entire flock to become alert. Apparently a female Goshawk could have a go at a Bean Goose but it is eagles they need to be more concerned about.

So the flock that had been together yesterday and was together for the start of today clearly broke up into smaller groups during the course of today. There was less wind today and it was also sunny which may have caused different behaviour. These geese are fascinating in terms of their choice of (traditional) staging sites and flock behaviour. The GPS data is answering many questions but the more you observe them the more questions are raised and hopefully volunteers like myself, Thomas and Brian and Angus in Scotland can help answer some of them.

Better light has allowed some better pictures and video today but it especially flight shots that, unusually for me, have come out well. I fired off loads of shots when the flock flew over us on its way north in the morning in the hope of getting some shots of leg rings. I have lots to go through and will post more later but here is one shot to decorate this post.
The two tagged birds are a pair 6Z and 6X and the other three are most likely their offspring

1 comment:

  1. Brilliant stuff Simon.

    As you indicate the parallels are huge. Indeed, in my reports on the bean geese I have frequently used the phrase, "the more we know, the less we know", spookily similar to your "the more you observe them the more questions are raised"!!