Why grey wagtail is a little off colour

I HAD an unusual visitor to the bird table the other day — a grey wagtail. This has to qualify as the bird with the most inappropriate English name.

The pied wagtail is black, white, and grey. This is the common ‘willie wagtail’ found everywhere, in towns and the countryside. I regularly visit schools, and, for some reason I don’t understand, pied wagtails have a passion for school yards. I don’t think there’s a school in the country that doesn’t have a pair.

The grey wagtail is nothing like as common. It is a slimmer bird, with an even longer tail that it continuously wags up and down. The most striking characteristic of the grey wagtail is its under-part, which is bright, primrose yellow.

It should be called the yellow wagtail, but, unfortunately, this name has been taken by another species that has even more yellow.

True yellow wagtails are rare in Ireland. They turn up as occasional passage migrants, in coastal areas, in spring and autumn. They have bred in this country and there’s evidence that this is becoming more frequent.

The grey wagtail that visited my bird table, the other day, was nothing like such a rarity. There are estimated to be 22,000 breeding pairs in the country, but they have a localised distribution and this is only the second time in 25 years that I’ve recorded one in the garden.

It wasn’t actually on the bird table; it was hopping around on the ground underneath. I watched for a while, in the hope that it would fly up to investigate what all the other birds were feeding on, and I would legitimately be able to add another species to the bird table list. But a tractor drove down the lane and scared it off, and I haven’t seen it since.

Grey wagtails are water birds. They specialise in shallow, rocky streams, particularly in upland areas. In the lowlands round here, you will spot them on rivers, like the Liffey and the Barrow, but usually around weirs, where there is increased water flow.

They’re also found on the canals, but almost exclusively around locks. The attraction of locks is not just the increased water flow around them. The birds nest in rock crevices, and the gaps between the limestone blocks in a lock are ideal.

They also get very excited if a lock is emptied, flying down to prey on any underwater invertebrates that have got marooned, in the vegetation lining the lock chamber, by the rapidly falling water level.

My house is many kilometres from the nearest suitable habitat for grey wagtails. But both the occasions that I’ve seen them in the garden have been in autumn, and the weather has been unusually cold.

In these conditions, which are tough on a species that feeds on invertebrates, there is some passage migration among grey wagtails. We don’t know if this seasonal movement only occurs within Ireland, or whether there is international migration.

Part of the problem is the fact that grey wagtails are not often trapped by bird ringers. But at least one bird that was ringed in Scotland has turned up in Ireland, so there probably is some true migration.

I know from the feedback that I get that many readers of this page keep a close eye on the birds that visit their gardens. The type of seasonal movement that brought the grey wagtail to my garden, the other day, occurs among many bird species at this time of year, so you expect a few unusual things to show up in the next few weeks.

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