Hybrid Common x Black Redstarts

As our second plate illustrates, the main pitfall for identifying an Eastern Black Redstart in the Western Palearctic is a hybrid Common x Black Redstart. These are reported regularly from central Europe (Martinez et al 2019), and Arnoud recorded one in the town of Harlingen, Friesland, in June 1990, taking notes about its plumage, song and vocal behaviour.

In plumage, the Dutch bird was most like a male Common Redstart but with more black below the throat and onto the upper breast, and more rufous lower parts than in Common. Unlike Black subspecies, it had a clear white forehead, pale greyish upperparts, and greyish brown wings, just like Common. Despite the lack of genetic proof, based on plumage the concensus was that this had to be an F1 hybrid.

The bird was tricky to record, never continuing for long periods and remaining difficult to approach in a built-up area. It sang from roofs, antennas, chimneys and even from inside a ship under construction at the ‘Welgelegen’shipyard, ie, Black Redstart rather than Common Redstart habitat. According to Arnoud's notes the song resembled that of a Black Redstart but without the scratchy, hissing bit typical for Black, and with the occasional strophe sounding more typical of Common. At one point it stayed still long enough for Arnoud to make a short recording.

Common x Black Redstart Phoenicurus phoenicurus x ochrurus Harlingen, Friesland, Netherlands, 2 June 1990 (Arnoud B van den Berg). Song of a hybrid. Background: House Sparrow Passer domesticus. 900602.AB.110000.01

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Eastern Black Redstart Phoenicurus ochruros rufiventris Xining, Qinghai, China6 June 2009 (Hannu Jännes). Song of a male. Background: sparrow Passer.

The three songs in the recording have a structure that more closely resembles Common Redstart than Black Redstart, a short fanfare followed by a series of imitations. The first fanfare is like Common though faster than most nominate phoenicurus, while the second is indistinguishable from a Black Redstart fanfare. The imitations that follow include Western Bonelli's Warbler Phylloscopus bonelli, possibly Eurasian Blue Tit Cyanistes caeruleus and certainly European Greenfinch Chloris chloris, European Goldfinch Carduelis carduelis and European Serin Serinus serinus.

Martinez et al (2019) collected literature, recordings and personal reports on hybrid redstarts and mixed singers and were able to describe some general patterns. Out of 55 individuals for which recordings or information was available, 67% sang like Black Redstarts, 22% gave either a mixed song or songs of both parents, and 9% were reported to sing like Common Redstarts. In other species pairs, like Common Nightingale Luscinia megarhynchos and Thrush Nightingale L luscinia or Melodious Warbler Hippolais polyglotta and Icterine Warbler H icterina, when their songs come into contact, one of the two dominates and the other adapts to sound more like it. Common Nightingale and Icterine Warbler are dominant in the above pairs (Constantine & The Sound Approach 2006). We suggest that Martinez has shown that Black Redstart is the dominant bird in this case.

Arnoud did not make any notes about the calls of the hybrid in Harlingen, but Martinez et al (2019) report hybrids commonly giving calls of both species.

In practice, if a Black Redstart with an orange belly sings crystallised song in Europe in spring, it is overwhelmingly likely to be a hybrid. Conversely, if you see a bird in late autumn or winter looking like an Eastern, it is likely to be the real deal. Hybrids and mixed singers are essentially a spring and summer phenomenon while Eastern turns up from October onwards, becoming diminishingly rare until spring (van der Spek & Martinez 2018).

This is the last of a series of ten articles. They were written in the hope they would be the backbone of a second edition of The Sound Approach to birding. There always seems to be so much more to learn. In conversation with Killian the other day, he pointed out how lucky we are to have a subject like birds as our interest, as he was sure birding was the elixir for eternal life.

Coming soon: The Sound Approach guide to waders.

 

Ayé, R, Martinez, N & Stalling, T 2014. The vocalisations of 'Ehrenberg's Redstart'. British Birds 107: 26-36.

Buxton, E J M 1945. On the nuptial displays of the redstart. British Birds 38: 282-287.

Buxton, J 1950. The Redstart. New Naturalist Monographs. London.

Callahan, D 2020. Focus on: Black Redstart. https://www.birdguides.com/articles/species-profiles/focus-on-black-redstart/

Catchpole, C K & Slater, P J B 2008.Bird song. Biological themes and variations. Second edition. Cambridge.

Comolet-Tirman, J 1994. Le chant imitatif du Rougequeue à front blanc (Phoenicurus phoenicurus): une étude en forêt de Fontainebleau, Seine-et-Marne, France. Nos Oiseaux 42, 267-277.

Constantine, M & The Sound Approach 2006. The Sound Approach to birding. Book with two audio CDs. Poole

Cramp, S (ed.) 1992. Handbook of the Birds of Europe, the Middle East and North Africa. Volume VI - Warblers. Oxford.

Hogner, S, Laskemoen, T, Lifjeld, J T, Porkert, J, Kleven, O, Albayrak, T, Kabasakal, B & Johnsen, A 2012. Deep sympatric mitochondrial divergence without reproductive isolation in the common redstart Phoenicurus phoenicurus. Ecology and Evolution. doi: 10.1002/ece3.398

Martinez, N, Nicolai, B & Spek, Vincent van der et al 2019. Redstart hybrids in Europe and North Africa. British Birds 112: 190-210.

Martinez, N & Martin, R 2020. Geographical variation in Common Redstart calls. Dutch Birding 42: 163-174.

Niemann, D 2013. Birds in a Cage. London.

Rasmussen, P C & Anderton, J C 2012. Birds of South Asia. The Ripley guide 2. Second edition. Barcelona.

Robb, M, Lopez-Velásco, D & The Sound Approach 2020. Nocturnal flight calls of Black Redstart: an unexpected discovery. https://books.soundapproach.co.uk/nocturnal-flight-calls-of-black-redstart-an-unexpected-discovery/

Sample, G 1996. Collins Field Guide: Bird songs and calls. Book and two audio CDs. London.

Sample, G 2006. Collins Field Guide: Wildlife Sounds of Britain & Ireland. Book and audio CD. London.

Sample, G 2010. Collins Bird Songs & Calls. Book and 3 CDs. London.

Schreur, G, Mayordomo, S & Langlois, D 2020. Fifty species in an hour: the remarkable mimicry of Common Redstart. BirdGuides. https://www.birdguides.com/articles/ornithology/fifty-species-in-an-hour-the-remarkable-mimicry-of-common-redstart/

Thomas, A 2020. RSPB guide to birdsong. London.

Thorpe, W H 1961. Bird-song. The biology of vocal communication and expression in birds. Cambridge monographs in experimental biology 12. London.

van der Spek, V & Martinez, N 2018. Identification and temporal distribution of hybrid redstarts and Eastern Black Redstart in Europe. Dutch Birding 40: 141-151.

Zendel, B R, & Alain, C 2012. Musicians experience less age-related decline in central auditory processing. Psychology and Aging, 27(2), 410–417. https://doi.org/10.1037/a0024816