Thursday 10 November 2011

Vismig nears its end for another year - Report on Thrush Numbers

I have been out earlier, but it was heavy rain, so gave that up after one hour and came home, and went out again around the 0830hrs mark, this time going up on the other side of Hutton Roof at Dalton Crags. By then it had stopped raining, but really dull, dark and dismal to the sides making visability very local. A sort of ghostly quiet sky, with nothing happening whatsoever. The only birds to record, where large groups of Blackbirds, and also a party of about 10 Redwing feeding up and resting in Dalton Crags.

Well I suppose its that time of the year once again, and for me it’s the winding down period. In regards to Thrushes, I’ve always considered that if the birds are not in by bonfire night, then that’s it, and that’s always rang true now for many years. I wonder if this year will be the same or are there going to be little burst every now and again of fresh arrivals.

Certainly this year, we have had it so mild, with only one night of substantial frost to call. Has it been a similar weather pattern over in the Baltics or the Scandinavia’s, Could this mild weather have prevented birds from coming over here. If the weather is still mildish over there and there is still plenty of food, why would they bother to come over here, YET.

This year in particular was very strange, first of all I had both Redwing and Fieldfare arrive on the same day eg: Tuesday October 11th 2011 – a party of 9 which consisted of 5 Fieldfare and 4 Redwing. As a rule the bulk of the Fieldfare are recorded in most cases to be about 10 days later than the Redwing.

Normally I would get the bulk of the Redwing “main push” on or around the 16th October, and the bulk of the Fieldfare “main push” on or around the 26th October. This year, especially in the case of the Fieldfare, they started to come in so early as shown in the example, and it was even more strange to record such a early “push” day with this species, eg: (Friday October 14th 2011 and good but reduced counts for the follow up two days also).

I’ve also thought that when Thrushes are on their first major push, which this year was on Friday October 14th 2011 (Fieldfares only). That if the bulk don’t arrive or are not on their way during the same time of that initial push (eg: that day and the following 2 days), then I am of the opinion, we are not going to get them.

I am now beginning to think that this year we have probably missed observing them. For me the reasons we have missed them, is through them over flying us at very high altitude. I am sure that this is very common every year, and more so in weather favourable years than others, and as such some years you will get good records and other years poorer records. Possibly this year was a good favourable weather situation for the birds in mid October and they were able to pursue their migrations at such high altitude leaving us with a much poorer records year.

I have in the passed experienced on no less than three separate annual occasions that the weather conditions have been so good for the birds, that they are flying at high altitudes, and when checking out with my binoculars, a party already high at cloud base, have then noticed, yet another party resembling just ever so small black dots, going through at a far greater high altitude than the first party. And if you hadn’t been lucky enough at that time to have been checking the first party with your binoculars, then I’m afraid you would have missed them (Quite easily). When this is the case, I think it could be well possible that we get lower counts than we probably expected. Yet even in these “bird favourable weather” conditions, we do get birds also at lower and mid altitudes as well.

Also, I suppose another possibility in regards to a shortage of thrushes could be that although the onset of the migration had started off OK with good weather during the earlier crossing, and then the weather turned to more unfavourable conditions, that the follow up birds, may decide to not bother with their intended North Sea crossing, and instead head South down the mainland.

Yesterdays belated vismig report:

Visible Bird Migration – Wednesday November 9th 2011.Hutton Roof, Cumbria.
0700hrs – 0900hrs
Wind: E 5mph
Movement: South unless stated.

Redwing: 77 (11W 66E)
Fieldfare: 56 (25SW 31SE)
Blackbird: 1 W
Mistle Thrush: 1 E
Alba Wagtail: 1
Chaffinch: 88 (E & W)
Goldfinch: 3 E
Siskin: 2 E
Greenfinch: 6 E & W

Also could hear Golden Plover but not seen.