Taking stock of visitors to my bird table

LIKE many people with an interest in wildlife, I keep track of the birds in my garden.

Because I’ve been doing this for many years and because I have a large and unruly rural garden the list of species is now quite long. In fact it’s somewhere around 40 to 42 species, despite the fact that I never get water birds or seabirds like gulls.

I can’t arrive at a definitive number because I can’t decide what actually constitutes a bird in my garden. A pair of ravens regularly flies overhead but I’ve never seen one land on the property – does that count?

A couple of times I’ve seen a kestrel hovering over the rough bit hunting mice. I’ve never seen it stoop to catch one but it was definitely hunting over my land so I’m inclined to include it. But I can’t bring myself to add to my list of garden birds the skein of Greenland white-fronted geese that crossed over the property at high altitude on migration.

I have another, much shorter, list of birds that have visited my bird table and feeders. It stands at around 15. Again there are ethical problems. The bird table has a twiggy branch sticking up in the middle of it. I have spotted a few bird species perching on this branch but not seen them feeding. They may just have been taking a rest or maybe they were curious about what all the other birds were up to. Do they count?

This category includes a pair of long-tailed tits, a cock bullfinch and a pied wagtail.

There’s another problem posed by birds that hop around on the ground below the bird table and occasionally pick up bits of spilt food. I’m inclined to think that these do count and that I could add dunnock, blackbird and song thrush to my list. There was also the case of the flock of small birds that suddenly descended on the feeders one day last winter. The flock definitely contained siskins, linnets and goldfinches and I think there were redpolls in it too but I can’t be sure. They all flew off before I could get my binoculars and left me adding ‘redpoll???’ to the list.

Of course, it doesn’t matter in the slightest. They’re just lists for my personal interest not pieces of scientific work. What is slightly more important is observing the behaviour of the birds and learning a bit about them. And when you’ve been doing this for a number of years it’s also useful to monitor changes in population numbers. Birdwatch Ireland does this in its Garden Bird Survey, which has been going on for 15 years now, and they do a proper scientific analysis of the results.

But even with the best scientific analysis you can sometimes get misleading information. If I look at my own tallies and at the figures on the Birdwatch website (www.birdwatchireland.ie) it looks as though there has been a massive increase in the number of goldfinches in this country over the past decade. In fact what these figures show is that at some point in the recent past goldfinches learned for the first time to utilise feeders. There may be a slight population increase but the massive spike in the graph is actually caused by a change in behaviour. I suspect something similar may be causing a huge increase in the number of house sparrows visiting my feeders this winter. Though it does seem that this species, which was causing concern among conservationists, is starting to increase in overall numbers.

And sadly it looks as though a decline in the number of greenfinches in my tallies and in the official ones genuinely indicates that this bird is in trouble because of a disease caused by a parasite.

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