The list that I published yesterday (to which I have gone back and added starling which I inadvertently omitted) does not actually say anything about the incidence of those birds or patterns in their appearance. For example song thrushes used to be common and we had some nesting a few years back, but the one I saw the other day on the apple tree at the back of the garden came as a pleasant surprise as they have been scarce here in recent times.
Similarly greenfinches and chaffinches were at the feeder all of the time until the hard winters of a couple of years ago took their toll. 2011 was notable for seeing mainly dunnocks in the garden whereas 2012 saw surprisingly large flocks of house sparrows.
The winters of 09-10 and 10-11 definitely had a massive impact and in terms of diversity of species we haven't recovered, at least within the four corners of our garden. On the other hand the prevalence of sparrowhawks suggests the opposite - the numbers of apex predators is a decent indicator of the quantity of prey available and, all things being equal, this is a self-regulating relationship. Perhaps the correlation is with the numbers of particular prey species, such as sparrows.
In any event I'm hoping that the relatively benign winter we are currently enjoying will mean plenty of surviving insects and therefore plenty of fledglings come spring.
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