Yellow Wagtail (Motacilla flava)



Yellow Wagtail © Steve Round

Yellow Wagtail © Steve Round

“Cheshire would appear to be the county for the Yellow Wagtail”, declared Stuart Smith in his New Naturalist monograph (1950) but this claim could never be made today. The Atlas map shows that they are now all-but lost from Wirral and the east of the county, and are scarce in most parts of the south-west of Cheshire. They have gone from the south Manchester fringe, including Smith’s study area at Gatley, lost under motorway building and just over the county boundary in Greater Manchester. Nationally, the species is on the amber list of conservation concern, and due to be red-listed at the next revision, owing to their massive decline. Much of this loss occurred between our two Atlas periods; the BTO’s CBC/ BBS population index shows a fall of 64% from 1984 to 2004. This is almost the same as the fall in the number of occupied tetrads in Cheshire and Wirral, down 67% from 386 tetrads in 1978-84 to 126 tetrads in 2004-06.

Possible reasons for the reduction have been given as farmland drainage, the conversion of pasture to arable land, the change from spring to winter cereals, and the loss of insects associated with cattle (BTO Second Atlas, Nelson et al 2003). British Yellow Wagtails winter in damp habitats in the westernmost parts of trans-Saharan Africa, in similar areas to those in which many other species have suffered population declines.

They take their prey of small invertebrates from on or near the ground, by picking or flycatching in short sallies. Their traditional association with livestock, birds often feeding around the heels of large animals, no longer seems to hold. Similarly, the Yellow Wagtail’s favoured habitat has been damp meadows and marshes, but nowadays it seems to be mainly in agricultural land, especially areas of arable or mixed farming (Brown & Grice 2005). The submitted habitat codes showed 85% of the records in farmland, with 8% in semi-natural grassland/ marsh. In 30 tetrads (22% of the records) they were associated with arable land, a higher proportion than for any other species, and there were 31 records in improved grassland and 32 in mixed grassland/ arable land. This preference applies at a local scale, but there is, however, no correlation across the county between the distribution of arable land, either cereals or horticulture, and the map of Yellow Wagtails.

They can be conspicuous when feeding chicks, and 37 of the confirmed breeding records were FY, with a further 15 of recently-fledged young. An unusually high proportion of records from fieldworkers included comments about the nesting area of Yellow Wagtails. In twelve tetrads birds were reported nesting in agricultural crops: in four of them the nest appeared to be amongst potatoes, with another two in beans. One was in maize, one ‘in bare patches in autumn sown wheat’, and 4 in unnamed ‘cereals’. In a further two tetrads with confirmed breeding they were benefiting from set-aside land. They nest on the ground, usually choosing a site under a large leaf, and lay 5 or 6 eggs in mid-May. I found that the median hatching date of 14 nests on Frodsham Marsh in the 1980s and early 1990s was 1 June. In the years when they nested earliest, 1988 and 1989, three pairs went on to have second broods in a new nest just five weeks later.

The BTO BBS analysis estimated the breeding population of Cheshire and Wirral in 2004-05 as 550 birds (with wide confidence limits from zero to 1,240), corresponding to an average of three or four pairs per tetrad with confirmed or probable breeding, or two pairs per tetrad in which the species was recorded. This is only about one-third of the estimated total during our First Atlas.

The distinctive race flavissima (the yellowest) occurs almost entirely in Britain but plumage variations are encountered quite frequently. Most of these aberrants arise from mutations because the species is obviously in a state of genetic flux (Smith 1950). Sometimes such birds are claimed to be of a different race but the County Rarities Panel received no convincing record of any other than flavissima breeding during the three years of this survey.

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