Thursday, February 10, 2011

9th February,2011

Who mentioned the weather? A dreadful day that got worse as time went on. Rain, mist, poor visibility generally made it pretty miserable. Despite this we still attempted a goose count and, thankfully, managed to complete things before the worst of the rain.

The most interesting part of the Gruinart route was on the Ardnave peninsula with 29 Chough in a flock, about 120 Twite and three Skylark. For some reason the geese seemed very edgy and constantly on the move, which is not the best circumstances to count in!!

Later, discussions with a colleague on our intention to try and count any/all active heronries on Islay, which has not been done for many years in any systematic way. We also touched on harrier movements on Islay. Many of our harriers appear to leave Islay in winter, but not all. Indeed there is a noticeable increase and movement of harriers through Islay, presumably from elsewhere , in October each year. Despite efforts over the years I've singularly failed to establish where any new communal roosts are present, in addition to the known small roost present at the RSPB reserve at Gruinart. I suspect many birds must simply roost individually and with sites changing regularly too. Over the last couple of days there appears to have been odd "new" male birds around at well spaced locations, which possibly indicates their return. Some harriers have been present on the Oa throughout the winter, drawn by the presence of the large accumulations of passerines, numbers of which are now beginning to reduce as the food source dwindles. It's also of interest to dwell on the distance such birds can move in a day. Following the web site which shows results from the birds fitted with radio transmitters in the Highlands shows movement over quite extensive "loose" territories. This means care has to be taken when attempting to establish numbers present based simply on observations outside of the breeding season (when individual territories can be determined). In this context I'm always amused by claims , and statements , from some visitors that "harriers were all over the place" and "we saw .... harriers during the day", as deciding actually how many are around is not as straight forward as might first appear!!! Another aspect is that they can "appear to disappear" for intervals. The pair local to home appear to have been around for most of the winter, but with some periods when they are not seen for a few days. Their use of their feeding territory also appears sometimes to have some regularity associated with it with birds being seen at "fixed" times each day over a period of time! I guess there's still a lot we need to find out and I suspect, with the advent of new tracking technology, much will emerge over the next few years that is fascinating in the extreme!!

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