01/01/2010
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Common and Black Redstarts

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Black Redstart by Steve Young
Black Redstart by Steve Young

Key featured species

  • Black Redstart Phoenicurus ochruros
  • Common Redstart Phoenicurus phoenicurus
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The problem

Adult males of the two species are easily identified, but females and first-winters are similar, although there are some intriguing differences.

The solution

Habitat and timing

Common Redstart is a summer visitor from late March to October, and almost unknown in winter. It is associated mainly with mature deciduous woodland in upland areas of the north and west. On migration, it is a bird of trees, hedges and bushes.

Black Redstart is very much an urban species, being surprisingly common in towns and villages on the Continent. In Britain it breeds in small numbers – fewer than 100 pairs – concentrated in the South-East. It is much more familiar in late autumn when significant influxes may occur, particularly into south-west England; for example, there were about 200 on St Mary’s, Scilly, on 16 October 2005. Smaller numbers remain over winter, particularly in milder coastal areas of the south and west.

On migration, Black Redstarts occur in a variety of open habitats, such as ploughed fields, rocky coastlines and along the tide wrack of sandy beaches. In autumn, however, migrating Common Redstarts may occur in exactly the same places.

Juveniles

In their first plumage after they leave the nest, juvenile Black Redstarts are basically plain grey, like their mothers, whereas juvenile Common Redstarts are heavily spotted, similar to juvenile Robin. In both species, juvenile plumage is lost in a late summer body moult prior to migration, but juvenile Common Redstarts often disperse from their breeding areas in July and such birds may still show extensive pale spotting on their upperparts and underparts.

Females and first-winters

In their most familiar plumages, both are plain and featureless with a large dark eye set in a plain face; this is surrounded by a narrow eyering.They are sleek, energetic birds, swooping down to the ground to pick up their insect prey. On landing, the tail is often ‘shimmied’, revealing the dark orange rump, uppertail coverts and outer tail feathers.

They are easily separated by plumage tone. Black Redstart is a plain, dark smoky-grey, appearing rather drab and undistinguished at any distance. Common Redstart is greyish-brown above and buffy-brown below, with brighter birds showing soft orange tones. The throat is paler, as is the lower breast, belly and undertail coverts. It is interesting to note that, prior to their moult in late summer, some worn female Common Redstarts, perhaps mainly older birds, acquire male-like characters such as white mottling on the forehead and dull black on the face (Cramp 1988).

Autumn male Common Redstarts

Adult males undergo a complete moult in late summer. In autumn, the new plumage has fresh pale feather fringes, so that their ‘full’ plumage is subdued. The black on the face is obscured by whitish feather edgings and the throat may thus look greyish at a distance.The white band on the forehead remains visible, extending back over the eyes.

Common Redstart does not have a winter body moult – the male’s ‘summer’ plumage is gradually revealed during the course of the winter as the pale feather fringes eventually wear away.

First-winter males are similar, but are even more subdued as the pale fringes are much broader. They show only a ghost of the ‘full’ plumage. As a consequence, the black face is more restricted while the white band on the forehead is ill-defined or even absent. As the rate of feather abrasion varies, there is much individual variation in the brightness of male Common Redstarts in autumn.

Autumn and winter male Black Redstarts

Like Common Redstarts, adult male Black Redstarts have only one moult a year, so ‘summer plumage’ is also acquired by the abrasion of feather tips, which are grey. In autumn, adult males can be distinguished by their black throats and breasts, with grey feather fringes, and by their white wing panels. First-winters males are more complicated. Most remain grey and ‘female-like’ and, as a consequence, all grey autumn and winter Black Redstarts should be aged/sexed as ‘female or first-winter male’.

Rarely, some first-winter males resemble adult males, having a largely blackish chin, throat and breast, with wide grey feather fringes that gradually wear off. As the feathers wear, these birds increasingly resemble adult males, but can be distinguished by the lack of a white wing panel and by their browner wings. These two forms are sometimes treated as plumage morphs, although some birds are intermediate. The commoner grey form is known as cairii while the rarer black-breasted form is aptly named paradoxus.The commoner cairii birds remain grey throughout their first summer and can often be heard singing in this plumage.

Calls

Another intriguing difference is provided by calls. Common Redstart is quite vocal, both on the breeding grounds and on migration.The most familiar call is a hueet, similar to that of Willow Warbler, but louder, clearer, fuller and more emphatic; it also tends to be given more incessantly.They also give an abrupt, hard, dry tp or tup alarm call, particularly when flushed.

Black Redstart, on the other hand, is an astonishingly silent bird; in fact, I have no recollection of ever hearing one call. Martin Cade, warden of Portland Bird Observatory, mentioned that he too could not recall hearing one. Grahame Walbridge, another Portland stalwart, told me that he never hears them on migration, but sometimes in winter. They then give a loud,‘impatient’ whistled weet, often repeated, which seems to be the equivalent of Common Redstart’s hueet. This call is usually given from birds on roof-tops and he thinks it likely that the call has a territorial function, which would explain why it is not given on migration.

Acknowledgements

Thanks to Martin Cade and Grahame Walbridge for their helpful comments. 

References

  •  Cramp, S. 1983. Birds of the Western Palearctic. Vol V. Oxford University Press, Oxford.
  •  Svensson, L. 1992. Identification Guide to European Passerines. Stockholm.

Ageing in detail

Autumn females
Svensson (1992) indicates that the ageing of females of both species in autumn is difficult. Whereas the adults’ greater coverts are of one age and uniform, some first-winters show a contrast between their fresh, adult inner coverts and slightly browner and more heavily worn juvenile outer coverts. Adult Commons have broader and more rounded tail feather tips, whereas those of first-winters are narrower and more pointed; this difference does not seem to  apply to Black Redstart.

Male Common Redstarts
As well as tail feather shape, male Commons can be aged by  the fact that adult males’ greater coverts are edged grey, whereas on  first-winters they are edged brown. This difference persists into the spring, when first-years remain duller than the adults; they also have browner and more faded wings that contrast more strongly with the grey of the back and scapulars (Svensson 1992).